PETRONAS TECHNICAL STANDARDS
Piping General Requirements
PTS 12.30.02
December 2017
© 2017 PETROLIAM NASIONAL BERHAD (PETRONAS)
All rights reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form
or by any means (electronic, mechanical, photocopying, recording or otherwise) without the permission of the copyright
owner. PETRONAS Technical Standards are Company’s internal standards and meant for authorized users only.
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FOREWORD
PETRONAS Technical Standards (PTS) has been developed based on the accumulated knowledge,
experience and best practices of the PETRONAS group supplementing National and International
standards where appropriate. The key objective of PTS is to ensure standard technical practice across
the PETRONAS group.
Compliance to PTS is compulsory for PETRONAS-operated facilities and Joint Ventures (JVs) where
PETRONAS has more than fifty percent (50%) shareholding and/or operational control, and includes
all phases of work activities.
Contractors/manufacturers/suppliers who use PTS are solely responsible in ensuring the quality of
work, goods and services meet the required design and engineering standards. In the case where
specific requirements are not covered in the PTS, it is the responsibility of the
Contractors/manufacturers/suppliers to propose other proven or internationally established
standards or practices of the same level of quality and integrity as reflected in the PTS.
In issuing and making the PTS available, PETRONAS is not making any warranty on the accuracy or
completeness of the information contained in PTS. The Contractors/manufacturers/suppliers shall
ensure accuracy and completeness of the PTS used for the intended design and engineering
requirement and shall inform the Owner for any conflicting requirement with other international
codes and technical standards before start of any work.
PETRONAS is the sole copyright holder of PTS. No part of this document may be reproduced, stored
in a retrieval system or transmitted in any form or by any means (electronic, mechanical, recording
or otherwise) or be disclosed by users to any company or person whomsoever, without the prior
written consent of PETRONAS.
The PTS shall be used exclusively for the authorised purpose. The users shall arrange for PTS to be
kept in safe custody and shall ensure its secrecy is maintained and provide satisfactory information
to PETRONAS that this requirement is met.
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Table of Contents
1.0
INTRODUCTION..................................................................................................... 7
SCOPE ........................................................................................................................... 7
GLOSSARY OF TERM ..................................................................................................... 7
SUMMARY OF CHANGES .............................................................................................. 8
2.0
PIPE SIZING ........................................................................................................... 9
GENERAL ...................................................................................................................... 9
3.0
PIPING BASICS..................................................................................................... 10
GENERAL .................................................................................................................... 10
DESIGN CONDITIONS ................................................................................................. 10
PIPING ABOVE GROUND LEVEL .................................................................................. 11
PIPING BELOW GROUND LEVEL ................................................................................. 14
PIPING FLEXIBILITY AND SUPPORTING....................................................................... 16
PIPING THROUGH WALLS, STRUCTURAL DECKS AND CONCRETE FLOORS OF
BUILDINGS .................................................................................................................. 16
SEISMIC LOADS........................................................................................................... 16
DISTANCE BETWEEN PIPES......................................................................................... 16
SMALL BORE PIPING................................................................................................... 17
INSTALLATION OF FLANGES ....................................................................................... 17
HYDRAULIC BOLT TENSIONING .................................................................................. 18
INSTALLATION OF VALVES ......................................................................................... 19
DRAIN AND VENT CONNECTIONS .............................................................................. 23
CONNECTIONS FOR MANUAL SAMPLING .................................................................. 24
TEST CONNECTIONS ................................................................................................... 26
THERMOWELL CONNECTIONS ................................................................................... 26
ORIFICE FLANGES AND ORIFICE METER RUNS ........................................................... 28
DISPLACER CHAMBERS............................................................................................... 28
INSTRUMENT PROCESS CONNECTIONS ..................................................................... 28
THERMAL EXPANSION RELIEF VALVES (TERVs) .......................................................... 29
GALVANISED PIPING .................................................................................................. 29
CHEMICAL INJECTION CONNECTIONS........................................................................ 29
CORROSION COUPON (CC) CONNECTIONS ................................................................ 30
CORROSION PROBES CONNECTIONS ......................................................................... 30
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SAND PROBE CONNECTIONS...................................................................................... 31
MODIFICATION TO EXISTING PIPING SYSTEM ........................................................... 31
4.0
PIPING ADJACENT TO EQUIPMENT ...................................................................... 32
GENERAL .................................................................................................................... 32
PUMP, COMPRESSOR AND STEAM TURBINE PIPING ................................................. 32
HEAT EXCHANGER PIPING.......................................................................................... 39
FURNACE AND BOILER PIPING ................................................................................... 40
PRESSURE VESSEL PIPING .......................................................................................... 40
RELIEF SYSTEMS ......................................................................................................... 41
LEVEL GAUGES ........................................................................................................... 41
INSTRUMENTATION ................................................................................................... 44
PACKAGED EQUIPMENT PIPING................................................................................. 44
PIG LAUNCHER AND RECEIVER PIPING ...................................................................... 45
SLUG-CATCHER PIPING .............................................................................................. 45
VESSEL TRIM............................................................................................................... 45
5.0
UTILITY PIPING .................................................................................................... 46
FIRE WATER ................................................................................................................ 46
COOLING WATER........................................................................................................ 46
WATER FOR OTHER PURPOSES .................................................................................. 47
STEAM ........................................................................................................................ 47
CONDENSATE ............................................................................................................. 49
INSTRUMENT AIR ....................................................................................................... 50
TOOL AIR .................................................................................................................... 50
UTILITY HOSE STATIONS............................................................................................. 50
6.0
TANK FARM PIPING ............................................................................................. 51
GENERAL .................................................................................................................... 51
PIPING CONNECTIONS ............................................................................................... 52
7.0
PIPING FOR LOADING AND UNLOADING FACILITIES ON JETTIES ........................... 53
GENERAL .................................................................................................................... 53
8.0
PIPING COMPONENTS ......................................................................................... 54
GENERAL .................................................................................................................... 54
PIPE ............................................................................................................................ 54
PIPE JOINTS ................................................................................................................ 55
FITTINGS ..................................................................................................................... 59
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BRANCH FITTINGS ...................................................................................................... 60
FLANGES ..................................................................................................................... 60
ISOLATION .................................................................................................................. 61
POSITIVE ISOLATION (“SPADING”) ............................................................................. 66
VALVES ....................................................................................................................... 68
9.0
INSPECTION AND TESTING .................................................................................. 76
SHOP-FABRICATED OR MANUFACTURER-SUPPLIED PIPING...................................... 76
FIELD-FABRICATED PIPING ......................................................................................... 76
VALVE INSPECTION .................................................................................................... 76
PRESSURE TESTS......................................................................................................... 76
10.0
INSULATION ........................................................................................................ 77
THERMAL INSULATION............................................................................................... 77
ACOUSTIC INSULATION .............................................................................................. 77
11.0
PAINTING AND COATING..................................................................................... 78
12.0
BIBLIOGRAPHY .................................................................................................... 79
APPENDIX 1
: PIPE SIZING ......................................................................................... 87
APPENDIX 2
: PRELIMINARY SIZING OF PIPES CONTAINING LIQUID ............................ 99
APPENDIX 3
: FLOW RATES FOR PIPES CONTAINING LIQUID OR GAS ........................ 102
APPENDIX 4
: FRICTION FACTORS AND ROUGHNESS FACTORS FOR FLOW IN PIPES .. 104
APPENDIX 5
: SIZING OF STEAM PIPES WITHIN PROCESS PLANT AREAS.................... 106
APPENDIX 6
: PRESSURE DROP IN STEAM PIPES NOT COVERED IN APPENDIX 4 ........ 111
APPENDIX 7
: PRESSURE DROP IN CARBON STEEL WATER PIPES AT 2 °C................... 113
APPENDIX 8
: VISIBLE LENGTH OF PLATE-TYPE LEVEL GAUGES IN RELATION TO
STANDARD DISPLACER-TYPE LEVEL INSTRUMENTS FOR ASME RATING
CLASSES 150, 300 AND 600 .................................................................. 116
APPENDIX 9
: ERGONOMIC VALVE POSITIONING ..................................................... 117
APPENDIX 10
: ADDITIONAL REQUIREMENTS FOR SPECIFIC SERVICES ........................ 118
APPENDIX 11
: PIPE SPANS FOR PIPES RESTING ON MORE THAN TWO SUPPORTS ..... 124
APPENDIX 12
: FLANGE FACE ALIGNMENT ................................................................. 127
APPENDIX 13
: TYPICAL ARRANGEMENT OF CONTROL VALVE MANIFOLDS ................ 132
APPENDIX 14
: MINIMUM REQUIRED WALL THICKNESS ............................................ 133
APPENDIX 15
: SUPPLEMENTARY REQUIREMENTS APPLICABLE TO UPSTREAM
FACILITIES ........................................................................................... 133
APPENDIX 16
: NON-WELDED PIPE JOINT USING ELASTIC STRAIN PRELOAD FITTINGS 140
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APPENDIX 17
: SOUR SERVICE REQUIREMENT FOR UPSTREAM PIPING ...................... 146
APPENDIX 18
: WET H2S SERVICE REQUIREMENT FOR DOWNSTREAM PIPING ........... 158
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INTRODUCTION
This PTS provides minimum technical requirements and recommendation for piping system
design, fabrication, erection, inspection and testing in addition to requirements mentioned
in ASME B 31.3 and other relevant codes and standard. It also provides additional
requirements and recommendations based on PETRONAS lessons learnt and best practices.
This PTS applies to piping for all types of process fluids (including fluidised solids), and all
utility fluids.
SCOPE
1.1.1
The scope of this PTS is to design and construct the piping systems in accordance with
applicable ASME B31.3/ ASME B31.1/ ASME 31.5 (for package refrigeration unit) and as
supplemented by this PTS and PTS 12.30.05.
1.1.2
The scope covers design and installation for both upstream and downstream piping including
selection and requirements for piping for various fluids and system except for the piping
systems specified in Section 1.1.4 below. This PTS also specifies additional requirements for
specific services and precaution during construction and pre-commissioning for compliance
by Contractor.
1.1.3
The piping systems for package refrigeration units shall be designed, fabricated, erected,
inspected and tested in accordance with ASME B31.5 and, the impact test requirements shall
be considered in accordance with PTS 15.10.01.
1.1.4
Exclusions
The design and construction of the following piping system shall be exempted from the scope
of this PTS:
i.
Pipelines designed in accordance with ASME B31.4 and B31.8.
ii.
Oil and gas risers, hull piping subjected to Classification Society rules (except for
piping associated with topsides process systems including FPSO), subsea
systems, utility piping in living quarters and plant buildings.
GLOSSARY OF TERM
1.2.1
General Definitions of Terms & Abbreviations
Refer to PTS Requirements, General Definition of Terms, Abbreviations & Reading Guide PTS
00.01.03 for General Definition of Terms & Abbreviation.
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1.2.2
1.2.3
Specific Definitions of Terms
No
Term
Definition
1
Pipeline
As defined in para 803.1 of ASME B31.8
2
Piping
As defined in para 300.2 of ASME B31.3
3
Very Toxic
See PTS 16.50.01
Table 1.1: Specific Definition of Terms
Specific Abbreviations
No
Abbreviation
Description
1
AIV
Acoustic Induced Vibration
2
BNIF
Flanged branch fitting
3
BNIP
Plain end branch outlet fitting
4
DN
Nominal Diameter - in millimetres.
5
NPS
Nominal pipe size - in inches.
6
FIV
Flow Induced Vibration
PMRC
PETRONAS Materials Reference. The PMRC codes
are contained in the PMRC Database.
7
8
PMRC NAR
PETRONAS Materials Reference
Additional Requirement.
Table 1.2: Specific Abbreviations
Mandatory
SUMMARY OF CHANGES
This PTS 12.30.02 (December 2017) replaces PTS 12.30.02 (July 2014).
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PIPE SIZING
GENERAL
2.1.1
The following pipes with Nominal Diameter (DN) DN 15 (NPS 1/2), DN 20 (NPS 3/4), DN 25
(NPS 1), DN 40 (NPS 1 ½), DN 50 (NPS 2), DN 80 (NPS 3), DN 100 (NPS 4), DN 150 (NPS 6), DN
200 (NPS 8), DN 250 (NPS 10), DN 300 (NPS 12), DN 350 (NPS 14), DN 400 (NPS 16), DN 450
(NPS 18), DN 500 (NPS 20), DN 600 (NPS 24), DN 650 (NPS 26), DN 700 (NPS 28), DN 750 (NPS
30), DN 900 (NPS 36), DN 1050 (NPS 42) and DN 1200 (NPS 48) shall be used in accordance
with the following limitations.
i.
Sizes DN 15 and DN 20 shall not be used for long-run piping as they are
susceptible to damage and have limited mechanical strength.
ii.
Nominal pipe shall not be less than DN 50 in pipe tracks.
iii.
Nominal pipe size shall not be less than DN 40 in pipe racks.
2.1.2
Pipes with nominal Pipe Sizes (NPS) 3/8, 1 ¼, 2 ½, 3 ½, 4 ½, and odd number sizes of equal
and above NPS 5 shall not be used.
2.1.3
Unless otherwise specified by Owner, the requirements of small bore piping and other piping
shall be complied with code and this PTS.
2.1.4
Unless economically justified otherwise, the range of pipe sizes above DN 600 should be
limited to the following, to prevent the purchase of many different sizes of pipe and fittings:
DN 750, DN 900, DN 1050 and DN 1200.
2.1.5
The pipe numbering system shall be in accordance with PTS 12.00.02.
2.1.6
The anticipated pressure drop for the preliminary pipe sizes shall be checked once the basic
pipe routes, number of valves, control valves, fittings, etc., are obtained.
2.1.7
Pipe sizing requirements and calculation to be performed by Process discipline. Refer to
Appendix 1 for details.
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PIPING BASICS
GENERAL
3.1.1
Optimum piping layout in terms of process requirements, ergonomics, operation, inspection
and maintenance is attained by proper routing of the piping. Hence, the number of flanges,
fittings, valves and welds shall be minimized. For layout of Onshore and Offshore facilities
refer to PTS 12.03.04 and PTS 11.22.06.
3.1.2
The piping classes cover the selection of piping construction materials which specify the
piping components in the PMRC. The following PTSs and PMRCs shall be utilized:
i.
PTS 12.30.01, PTS 12.31.01, and PTS 12.31.02
ii.
PMRC MAR PT (pipes), PMRC MAR FF (fittings and flanges), PMRC MAR VA
(valves), PMRC MAR BL (bolting) and PMRC MAR GS (gaskets and packing).
3.1.3
A specification for piping systems shall be compiled for each project in order to have fixed
working documents during a project and reference documents during the lifetime of an
installation. Piping classes which require modification by project shall be kept to a minimum.
3.1.4
For definition of temperature, pressure and toxicity levels, refer PTS 16.50.01.
3.1.5
PTS 12.30.06 shall be utilized for protective steam heating of piping systems.
3.1.6
When required, “Electrical Trace Heating” shall provide the heating of piping systems per PTS
13.13.02 where there is no steam production.
3.1.7
PTS 12.30.04 shall be utilized for pipe supports.
3.1.8
Appendix 11 shall be utilized for spans of straight pipe.
3.1.9
Due to the risk of chloride stress corrosion cracking, the use of 316/316L material for stainless
steel piping class for chloride containing services shall be limited to a maximum temperature
of 60oC. A suitable duplex stainless steel piping specification should be considered for design
temperature exceeding 60oC.
DESIGN CONDITIONS
3.2.1
A piping system shall be designed for the most severe conditions to which it may be
subjected. The following may determine the design conditions:
i.
steaming-out pressure and temperature
ii.
surge pressure
iii.
pump shut-off pressure
iv.
static pressure
v.
pressure drop
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vi.
vacuum caused by cooling and possible condensing of trapped medium
vii.
steam/nitrogen purge pressure
viii.
Cyclic pressure and temperature
3.2.2
Different piping classes may be used if different design conditions exist in one piping system.
To ensure that the more severe design conditions can never occur in the part of the system
with lower piping class, these “spec breaks” shall be placed appropriately. Unless otherwise
specified by the Owner, flanged connections shall be used as the spec. breaks between piping
classes of different materials.
3.2.3
In situations where in-line equipment (e.g. control valves) with a higher ASME rating class
than the run pipe is fitted, the connecting flanges shall have the same rating as the in-line
equipment and the same wall thickness as the pipe.
3.2.4
If a system operating above 0 °C is connected to a system operating at 0 °C or below, Process
discipline to perform temperature transition profile for proper selection of piping material
and indicate the “spec breaks” location and distance in the P&ID.
3.2.5
ASME B31.3 provides allowances for pressure and temperature variations for short period.
All such cases (e.g. Allocating a design pressure below the maximum surge pressure) shall be
subject to the approval of the Owner and shall only be considered if major cost reductions
can be achieved.
3.2.6
If an external pressure can only result from structural failure of equipment, failure of safety
devices or other unpredictable events, it shall not be taken in consideration when
establishing the design pressure of the piping.
3.2.7
Refer PTS 16.50.01 for the definition of various pressure and temperature levels.
3.2.8
Piping subject to sub-atmospheric pressure shall be designed for full vacuum.
3.2.9
Refer Appendix 10 for additional requirements of specific services.
PIPING ABOVE GROUND LEVEL
3.3.1
Piping shall be routed above ground level except for the services stated under (3.4).
3.3.2
In a plot area or a processing unit , piping entering and leaving shall be grouped together
where practical.
3.3.3
Inside-plot piping shall be routed on overhead pipe racks where practical. Usually the pipe
racks have a stanchion interval giving a span of around 7 m. Intermediate beams shall be
installed if the pipe diameters require closer supports. DN 40 is the smallest allowable pipe
size on pipe racks.
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3.3.4
If the span between the supports is too long for a pipe, the size of that pipe may be increased,
instead of additional supports being provided, if this is justified technically and economically
(the technical evaluation shall include the possibility of internal corrosion due to the slower
flow causing separation of corrosive liquid from the mixture). This decision is subject to the
approval of the Owner.
3.3.5
If a pipe rack forms a part of a structure, or is located next to a structure, the stanchions of
the pipe rack should be in line with the columns of the structure, to make optimal use of
space for incoming and outgoing pipes.
3.3.6
Equipment which is a potential source of fire shall not be located under pipe racks.
3.3.7
To ensure safe access of piping with instrument connections, it shall be routed appropriately:
platforms or walkways shall be provided if necessary (refer PTS 14.10.02).
3.3.8
To avoid any possibility of contaminating austenitic stainless steel, duplex stainless steel,
nickel alloy or 9% nickel steel components with zinc, care shall be taken. Galvanized items
situated in the vicinity of these components shall be shielded (e.g. with fire blankets) if hot
work is performed on them to avoid contamination. For components which are insulated, the
cladding is considered to be sufficient protection.
3.3.9
A forked pipe shall be designed and supported so that no excessive loads on equipment may
occur when one branch of the pipe is disconnected (e.g. during maintenance operations).
3.3.10 The connecting piping shall be designed so that small dimensional errors in construction can
be adapted where multiple nozzles are utilised (e.g. on air cooler banks).
3.3.11 Safety relief valve discharge piping shall be designed to withstand the dead loads and the
blow-off loads. Blow-off design loads shall take into account the most severe case, such as
possible flashing conditions and liquid entrainment in vapour flows.
3.3.12 Piping run at ground level shall be raised at least 500 mm above ground from bottom of pipe.
3.3.13 Refer PTS 16.73.01 for requirements of fire water pipes for onshore installation.
3.3.14 To provide space for expansion loops and to reduce the moments in the beams caused by the
weight and thermal expansion of the pipes in a pipe rack, the heaviest and/or the hottest
pipes should be located at the sides of the pipe rack.
3.3.15 The minimum elevation of the bottom of overhead piping shall be:
i.
6.0 m over railways
ii.
6.0 m over main roads
iii.
4.0 m for crane access
iv.
4.0 m for truck access
v.
2.7 m for fork-lift truck access
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vi.
2.1 m over walkways and platforms
NOTE: In some situations the lower side of the pipe supports or the supporting steel dictates the minimum
elevation of overhead piping.
3.3.16 In case of any extra requirement to above minimum elevations during engineering stage,
adequate clearance shall be provided.
3.3.17 For access ways and walkways, there shall be a minimum horizontal clearance of 0.75 m and
0.9 m for thoroughfares. Around manholes, a minimum of 0.75 m on each side of the
manhole and a minimum of 1.2 m directly in front of the manhole shall be provided clear of
obstruction to allow for entry and exit.
3.3.18 Pipe routings and crossings shall be on different, predetermined elevations.
The drain piping carrying crystallizing solutions (e.g. Benfield solution, Urea solutions etc.)
shall have the size of at least DN 50 and it shall be provided as close as possible to the tapping.
In addition, for safety considerations, provide an additional valve downstream of the drain
valve to avoid any loss of containment of solution due to passing of the first drain valve.
3.3.19 The insulation shall be reinstated if it is removed for any maintenance work before startup of
the system.
3.3.20 As a standard practice, any piping carrying crystallizing solutions shall be provided with the
heat tracing. Requirement for heat tracing shall be confirmed by Process discipline.
3.3.21 Wellhead flow lines
All flow line direction changes shall be made via standard tees with one capped end as target
for directional changes in the flow. For inspection and cleaning purposes, the first bend from
the wellhead shall have blinded flanges on the tees. In case of vertical flow lines, all
directional changes shall be provided with tees and blind flanges/ caps. All dead legs shall be
provided with suitable size of drain valve with blind flange.
3.3.22 Production/ Test manifolds
i.
Multi-slot production or test manifolds (with flow lines >8 nos.) shall utilize
extruded outlet branches (e.g. compact manifolds) in preference to reducing tees
or integrally reinforced branch connections. The number of branches in the
manifold shall also consider future flowlines requirement. Any deviations to
above shall be commercially and technically justified by consultant and agreed
by Owner. This shall be decided during FEED/Detail Engineering stage.
ii.
The use of Multi-Port Flow Selector (MPFS) can be considered in-lieu of Multislot production or test manifolds subject to feasibility and if found economical.
While selecting the MPFS the following requirement shall be met with:
a) The design of MPFS shall comply with API-6A, ASME Sec VIII Div.1 or Div.
2. Design for the body including all the nozzles and bonnet shall be
submitted for Owner’s approval.
b) For design that compliance to ASME Sec VIII Div. 2, “U2” stamping and
approval of design by ASME Board are required.
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c) FEA Calculations shall be carried out for the body complete with all
nozzles and for the Bonnet of the MPFS.
d) Prototype design test results duly approved by reputable Third Party
Inspector (TPI) shall be submitted for Owner’s review.
e) All end connections shall be flanged as per ASME B16.5 and shall have
access for operation and maintenance.
f) MPFS Stem to Remote Operated Valve (ROV) control system,
connections, torque requirement calculations etc., shall be provided for
Owner’s review and approval.
g) All isolation valves used in the package assembly shall be Tight Shut Off
(TSO) during Factory Acceptance Test (FAT) and operation for the design
life. These valves shall be in compliance with API-6D testing
requirements as a minimum and any additional test requirements as
specified in Owner’s technical specification. Valve used for this
application shall be of soft seated DBB for class rating 600# and above.
The valve shall comply with the respective PMRC and PMRC MAR
requirement.
h) FAT for the MPFS shall be carried out as per API-6A and API-6D. The FAT
shall be witnessed by TPI and/or Owner’s representative and shall also
be carried out in accordance with the agreed Inspection Test Plan (ITP).
i) Body of MPFS along with all the inlet and outlet nozzles shall be designed
and supplied as a one piece forging. All forgings shall be 100% UT and
witnessed by TPI and/or Owner’s representative.
j) In cases where casting material for any pressure or load part is proposed,
it shall be submitted for Owner’s approval. In all cases it shall be 100%
radiographed, and witness by TPI and/or Owner’s representative.
k) For sour service application, the forgings and castings shall be HIC tested
and certified in accordance with ISO 10474 Type 3.2. All other
certifications shall be in accordance with Type 3.1 as minimum.
l) Suitable welded lifting lugs shall be provided. Bolted lifting lugs shall not
be used.
m) SIL requirement for the MPFS and for the control system (along with its
instrumentations) shall be agreed by Owner during detailed engineering
stage.
PIPING BELOW GROUND LEVEL
3.4.1
Buried piping
i.
Buried piping shall be considered for:
a) drainage or sewage
b) fire water and other water pipes, for protection against heat or frost
c) large-diameter pipes (e.g. main cooling water pipes) so as not to impede
traffic.
ii.
Buried piping shall have a minimum cover of soil from top of pipe as shown
below. In area that require more cover of soil, it shall be provided accordingly
during engineering stage:
a) fire water pipes (mains)
0.6 m
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b)
c)
d)
e)
f)
g)
h)
3.4.2
in areas inaccessible to heavy traffic
in areas accessible to heavy traffic and at road crossings,
pipes of DN 600 and smaller
pipes over DN 600 (including fire water pipes)
pipes crossing beneath railways (from top of sleeve)
in areas where only night frost can be expected
in areas where daytime freezing can be expected
0.3 m
0.6 m
0.9 m
1.2 m
0.6 m
0.7 m
iii.
The above soil cover depths depend on the outside temperature and the
permeability of the soil. In areas where prolonged sub-zero temperatures may occur,
the suitability of the above soil cover depths shall be confirmed.
iv.
The load on pipes crossing railways and roads should be equalized, e.g. by means of
pipe sleeves or a culvert. The pipes shall be kept centrally in the sleeves by distance
pieces welded to the pipe or fixed to the sheeting if the pipe is insulated for lowtemperature service.
v.
Insulated pipes should not be buried. If this is unavoidable, or if it is desired for lifecycle economic reasons, the insulation material shall be able to withstand the
stresses caused by the thermal expansion of the pipe. Special attention shall be paid
to avoid corrosion under the insulation and the system shall be designed so that
inspection is possible or not needed. For buried pipes operating above 60 °C, the pipe
shall be insulated to limit the outer surface (cladding) temperature to a maximum of
60 °C and there shall be a clear distance of at least 600 mm between the cladding
and any electrical or instrument cables.
vi.
In the design of underground piping, soil settlement and thermal expansion of the
piping shall be taken into consideration.
vii.
There shall be a clear distance of at least 300 mm between the pipe and any electrical
or instrument cables for buried pipes operating at a temperature of 60 °C or below.
This is applicable to non-CP protected piping system.
viii.
For buried pipes which have impressed current cathodic protection, there shall be a
clear distance of at least 1m between the pipe and any parallel-running cables, to
prevent stray-current corrosion of the steel wire armouring of those cables.
ix.
Piping shall be designed so that the complete system can be flushed and cleaned.
(e.g. “dead ends” should be avoided). For vents and drains, see (3.13).
x.
For buried pipe systems where the emission of aromatic hydrocarbons and/or toxic
fluids as defined in PTS 16.50.01 is a HSE concern (e.g. pollution of ground water)
xi.
Wherever bolted valves are used for buried piping, it shall be installed in pits with the
required extended bonnet. The pit shall be provided with suitable cover.
Pipe tracks and pipe trenches
i.
Piping outside process units (e.g. piping between process units and storage facilities)
should be supported by sleepers at ground level in pipe tracks and for below ground
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level should be routed in pipe trenches. If space at ground level is limited or if the
use of culverts or buried piping is wasteful, pipe racks may be used.
ii.
In accordance with Appendix 11, the distance between sleepers in pipe tracks and
in pipe trenches shall be based on the maximum permitted free span of the
majority of pipes .Smaller pipes requiring a shorter supporting distance shall be
grouped together and be supported on additional supports.
iii.
The elevation of the sleepers shall be such that there is access for maintenance and
for operation of valves, drains and instrumentation and that pipes and insulation will
remain above the highest expected storm water levels.
iv.
To prevent the buildup of gas and liquid vapours in the trenches, flanged connections
shall (PSR) not be installed in trenches.
v.
Process units, concrete trenches shall be sufficiently drained into a liquid-sealed
drainage system and shall be covered with grating.
PIPING FLEXIBILITY AND SUPPORTING
For piping flexibility and supporting shall be analysed in accordance with PTS 12.35.01.
PIPING THROUGH WALLS, STRUCTURAL DECKS AND CONCRETE FLOORS OF BUILDINGS
3.6.1
Sleeves or holes through walls and floors of buildings and through table tops shall have a size
permitting the passage of a flange of the relevant pipe size, or the size of the required
insulation, whichever is the larger, to allow the installation of prefabricated piping.
3.6.2
Penetrations through walls and floors shall be sealed with a hydrocarbon-resistant filler after
piping installation (e.g. a collar shall be fitted around the pipe) to avoid chimney draught in
the case of fire. To prevent liquid dripping onto a lower deck, holes shall be provided with
concrete curbs, cast-in extended pipes or other means. Where applicable the fire rating of
the wall or floor shall be maintained.
3.6.3
Piping penetrations through walls and floors shall be to a fire rating at least equal to that of
the wall or floor itself. Penetration details and proprietary penetrations/seals shall be subject
to Owner (Civil and Structure discipline) approval.
SEISMIC LOADS
For Seismic Loads Analysis shall be analysed in accordance with PTS 12.35.01.
DISTANCE BETWEEN PIPES
3.8.1
The minimum distance between pipes or the insulation of pipes in pipe tracks and trenches
and on pipe racks shall be 75 mm.
3.8.2
The minimum distance between a flange (with insulation) and a pipe or the insulation of a
pipe in pipe tracks and trenches and on pipe racks shall be 30 mm.
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3.8.3
The minimum distance between a flange (without insulation) and a pipe or the insulation of
a pipe in pipe tracks and trenches and on pipe racks shall be 75 mm.
3.8.4
Where required, the distance between pipes shall be increased to allow for movements
caused by thermal expansion.
3.8.5
The distance between the insulation of a low-temperature pipe and any other object shall be
at least 100 mm.
3.8.6
The distance between pipes shall allow for the turning of a spectacle blind, if present.
SMALL BORE PIPING
3.9.1
The following points shall be included in the piping design since small bore branches
40) to large bore piping are relatively vulnerable to failure:
(≤DN
i.
Minimize the number of small bore branches to piping.
ii.
All small bore nozzle welding shall be performed by Gas Tungsten Arc Welding
(GTAW) in the prefabrication yard or shop.
iii.
Small bore piping shall be shown in full detail, either on the isometric drawings
or on a referenced document.
iv.
Branches shall not be located in removable spools, unless it is impractical to do
otherwise.
v.
Branches shall not be located in high stress areas.
vi.
Branches shall be avoided downstream of high capacity gas pressure reducing
systems such as compressor recycle systems, steam desuperheaters, high-rate
depressuring valves and safety relief valves. If this is not possible, branches shall
be located well away from these sources of vibration based on vibration study
report. Special attention shall be paid to the bracing of these branches to the runpipe (see Standard Drawings D12.92.355, D12.92.356, D12.92.357). Welding of
the bracing to the run pipe/ flange shall be of full penetration type
3.9.2
All vents, drains, instrument branch connections of DN 40 and below in process lines, which
are to be connected to valves, a flanged branch fitting (BNIF) shall be used for the branch.
3.9.3
Avoidance of vibration-induced fatigue shall be ensured during design stage. AIV and FIV
study shall be performed for small bore connections susceptible to vibration induced fatigue.
INSTALLATION OF FLANGES
3.10.1 Flanges shall only to be installed in piping system to facilitate maintenance and inspection
and where construction or process conditions dictate.
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3.10.2 In the event of a flange leak in hydrogen service and services with flammable liquids at or
above their auto-ignition temperature, steam shall be used to control fires. The steam has a
smothering effect and will limit the overheating of flange bolts. Sufficient steam lances (see
Standard drawing D12.92.374) with 15 m long electrically-earthed hoses able to reach the
flanges shall be provided. Steam ring systems (see Standard drawings D12.92.347,
D12.92.348, D12.92.349) shall be fitted to inaccessible flanges unless it is assessed that a leak
would not present a serious hazard (this being subject to the approval of the Owner). In
assessing the latter risk, account shall be taken of the normal operating pressure of the
process, compliance with the selected piping class, use of bolt-tensioning equipment, type of
flange connection (end cover, pipe-to-pipe or pipe-to-equipment connection) and size of
flanges. Steam rings need not be installed on flange connections smaller than DN 150.
3.10.3 Steam rings shall be manually activated if they are installed. The steam block valves shall be
placed at a safe distance, at least 15m away from the flange and the related fire hazard. To
specify which steam ring they are serving, the block valves shall be marked correctly. At low
points, steam rings and piping should have 8 mm diameter drain holes.
3.10.4 For hydrocarbon services, flanges shall (PSR) not be located on the pipe bridge directly above
the road.
3.10.5 Bolts up to and including 1” shall comply with UNC standards.
1
3.10.6 Bolts of 1 /8” and larger shall have UN threading (8-thread series).
3.10.7 Nuts shall have a height equal to the bolt diameter.
3.10.8 Flange joint of dissimilar materials shall be provided with insulating gasket complete with bolt
sleeves and washers.
3.10.9 For insulating flanges and isolating joints in piping systems with Cathodic Protection - see
PTS 15.20.01 and PTS 11.32.01.
3.10.10 For flange alignment and tolerances, see Appendix 12.
3.10.11 Ring type joint (RTJ) flanges may be used for connection to wellheads or other proprietary
equipment/piping. In such cases the piping system shall have removable pipe spool with
flexibility for RTJ gasket maintenance.
HYDRAULIC BOLT TENSIONING
3.11.1 Hydraulic bolt tensioning shall be used for tightening the bolts of flanged connections of
equipment and piping where operating conditions require the stress distribution in the bolts
to be properly controlled to obtain a reliable joint. These conditions generally occur at high
pressure and elevated temperature in conjunction with a medium which is difficult to seal.
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3.11.2 Hydraulic bolt tensioning shall be applied in the following cases:
Service
All
ASME Rating
Classes
All
Bolt Diameter
(inches) (1)
≥ 2
All
≥ 1500
≥ 1½
Hydrogen
≥ 600
≥ 1½
All
≥ 1
Critical applications (to be agreed between the
Contractor and the Owner).
Note: 1) For new piping flange joint connected to existing piping flange which has no re-instatement testing been carried out,
torque wrench with required torque value shall be used for bolt sizes less than the above table
3.11.3 For bolt-tensioning equipment, see PTS 12.00.03.
Note: All pressure bolting shall be per respecting piping class (stud bolt with 2 heavy hex nuts)
3.11.4 For flange connection that exposed to thermal cyclic service conditions, bolt with tension
indicator (e.g.: Rotabolt) should be used.
3.11.5 Extra bolt length of 1 x Bolt Diameter shall be provided for bolts that require hydraulic bolt
tensioning. The bolt shall be provided with washer.
INSTALLATION OF VALVES
3.12.1 General
i.
The number of different make of valves in one particular facility shall be
minimised.
ii.
All pipes entering and leaving the process unit shall (PSR) have block valve(s) and
flanges provided to allow for positive isolation (spades or spectacle blinds) at the
boundary of the process unit (“battery limit”). The block valves shall be located
near each other unless impractical. A drain/vent connection shall be installed as
close as possible to the block valves and spades, for draining, venting and testing
purposes.
iii.
Valves in horizontal pipes shall be positioned with their stem on or above the
horizontal, except for the following:
a) butterfly valves shall be positioned with the stem horizontal in services
where fouling substances could collect in the lower shaft bearing
b) gate valves should be positioned with the stem horizontal in services
where fouling substances could collect in the bottom cavity
c) valves shall be positioned with the stem horizontal in systems where a
component failure (e.g. wedge pin) could cause closure of the valve and
lead to unsafe situations (e.g. flare systems)
iv.
Pipes with wafer and/or lug type valves may require an extra flanged connection
for installing a spade flange or removal of a pipe spool.
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3.12.2 Ergonomic aspects of valves
i.
The minimum distance between handwheels and any obstruction shall be 75
mm.
ii.
The location of valve handwheels and/or stems shall not obstruct walkways or
platforms.
iii.
Valves shall not be installed directly above roads in pipe bridge.
iv.
Valves should not be located in overhead pipe racks.
v.
Chain-operated valves shall not be used except with prior approval of the Owner
for specific applications (these valves are difficult to operate and the chain may
cause hazardous situations).
vi.
Critical valves:
For critical valves refer PTS 16.74.02: Human Factor Engineering - Valve Criticality
Analysis. .
vii.
Non-critical valves:
For non-critical valves refer PTS 16.74.02: Human Factor Engineering - Valve
Criticality Analysis.
viii.
Non-operational valves:
For non-operational valves refer PTS 16.74.02: Human Factor Engineering - Valve
Criticality Analysis.
3.12.3 Selection of gear drives for valves
i.
Gear drives shall be selected in accordance with the applicable valve PMRC MAR
specifications.
ii.
The selection of motorised actuators shall be subjected to the approval of the
Owner.
iii.
As a general guideline, the following valves should be equipped with power
actuators:
a) all shutdown valves
b) centrifugal compressor inlet and discharge valves. These valves should
close automatically on shutdown of the prime mover
c) divert, blowdown and other automatic valves
d) valves of the following sizes, if frequently operated:
-
ASME class 150
ASME class 300 and class 400
ASME class 600 and class 900
ASME class 1500 and higher
DN 400 (NPS 16) and larger
DN 300 (NPS 12) and larger
DN 250 (NPS 10) and larger
DN 200 (NPS 8) and larger
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3.12.4 Control valve installation
i.
Globe control valves shall be installed with their diaphragm actuator stem in the
vertical position, with sufficient clearance above the actuator and under the
bottom flange to allow the control valve to be dismantled without removing the
valve body from the pipe.
ii.
There shall be sufficient clearance to lift and remove the valve. Control valves
shall be located so that they are accessible for hoisting equipment where needed.
Further requirements for control valves are specified in PTS 14.10.04.
iii.
The bypass line shall not be located directly above control valve for line size DN
100 and above.
3.12.5 Manifolds for control valves
i.
Control valves shall be provided with block valves and a bypass valve if required
for operational reasons, except that a bypass valve shall not be provided in safety
shut-off or depressurizing service or in applications where solids suspended in
the stream may collect and block the bypass valve
ii.
The PFS and P&ID shall indicate the arrangement required for each application
and the provision of block valves, bypass valves, handwheels, etc. which is
governed by operational considerations
iii.
Except in the following situations where the block valves should be the same size
as the upstream/downstream piping, the block valves at each side of the control
valve shall be of the straight-through type and should be the same size as the
control valve:
a) if the additional strength of the larger pipe size is required for proper
supporting
b) if the size of the upstream/downstream process piping is DN 50 or
smaller
iv.
See Appendix 13 for typical arrangements of control valve manifolds.
v.
For critical applications, the bypass valve shall be of the same type as the control
valve, but with handwheel operation only. The bypass valve shall have a nominal
capacity factor at least equal to, but not more than twice, the capacity factor of
the control valve. The bypass valve shall be capable of proper throttling.
vi.
The bypass pipe shall be designed so that there are no vertical dead ends where
liquid can collect in the following services:
a) fouling process conditions
b) steam
c) hydrocarbons containing water
vii.
The control valve manifold shall be provided with facility to draining and/ or
depressurising. At least one drain valve shall be provided just upstream or
downstream of the control valve, depending of the physical lay-out. Shut-off
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valves shall have a drain valve on the downstream side so that the shut-off valve
can be leak-tested. In corrosive or very toxic service more extensive provisions
may be required.
viii.
Start-up strainers with labyrinth-type low-noise trims shall be provided upstream
of control valves.
3.12.6 Body cavity relief (pressure equalisation) provisions in valves
i.
Double-seated valves that are subjected to temperature changes and
consequent expansion of the liquid medium shall be provided with a pressure
relief device. Detail requirements for body cavity relief provisions in valves, see
PTS 12.32.02.
ii.
Body cavity over-pressure may occur in:
a) valves in steam/condensate systems when condensate is trapped
b) block valves around pumps during warming up prior to operation
c) valves in low temperature systems
iii.
This requirement is to avoid excessive pressure build-up in the cavity of doubleseated valves, where the medium (liquid) may be trapped.
iv.
Body cavity over-pressurisation (exceeding 33% of the rated pressure at
maximum design temperature according to the appropriate class) for soft-seated
floating ball valves, operating at temperatures between plus 260 °C and minus
50 °C, shall be prevented by ONE self-relieving seat assembly.
v.
Double metal-seated gate valves or metal-seated floating ball valves shall have a
pressure equalising hole drilled in the closure member outside the seat facing
area. The pressure equalising hole shall have a diameter of at least 3 mm.
vi.
The mechanical loading of spring-energised ball valves (side entry design) and
trunnion-mounted ball valves allows the seat to be pushed away from the ball to
enable pressure equalisation and for these valves the seats are self-relieving.
vii.
In order to avoid leakage through the closure member, the valve body cavity shall
be relieved to the high pressure side of the valve when the valve is in closed
position. The valve is now single-seated.
viii.
Normally the high pressure side is the upstream side of the valve, and in the
closed position the closure member will be pressed against the seat at the low
pressure side.
ix.
The pressure might act on the downstream side of the downstream valves
against the normal flow direction when the valves are in closed position in the
following situations,:
a) block valves upstream and downstream of pumps
b) control valve arrangement with block valves upstream and downstream,
and with a bypass
c) block valves upstream and downstream of relief valves
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x.
These valves shall be clearly marked “HP” and these positions shall be shown on
the P&ID and piping isometrics.
xi.
The condition whether the upstream or downstream side of the valve is the high
pressure side shall be specified in the purchase order.
xii.
The maintenance manual shall indicate how the closure member must be
assembled.
DRAIN AND VENT CONNECTIONS
3.13.1 As required for operation / maintenance and to facilitate performing future leak test for the
piping system, permanent valved drain connections shall be installed at low points, and
valved vent connections at high points in piping systems, unless otherwise agreed and
indicated in the project specification. These connections (including the valves, blind flange,
bolting and gaskets) shall be shown on the P&ID, piping model, piping-isometrics and in
material bulk take-off. This is to facilitate the piping system testing (during hydrostatic /
reinstatement / any future in-situ leak test that need to be performed during future
maintenance).
3.13.2 The process drain and vent shall be decided based on the process design and depends on the
required drain time. For both, test and process drains, the following minimum branch sizes
shall be used:
Run Pipe Size
Vent/ Drain Sizes
DN 40 – 50
DN 20
DN 80 – 300
DN 25
Larger than DN 300
DN 40
The type of branch connection shall be as per tabulation for the “Branch Connections 90
degrees” as given in respective piping classes.
3.13.3 For drain and vent provisions on equipment, see (Section 4 of this PTS). Gate valve flanged
(GAVF) of size DN 20 in-line with the respective piping class shall be used for these vents and
drains. Valved vents and drains to atmosphere shall satisfy the double barrier concept, as
indicated in Section 3.12.1 of this PTS. However, in this context where the flanged valve will
be provided with a standard blind flange (complete with bolting and gasket), the blind flange
counts as one barrier. This means that the blind flange on a single valve should only be
removed after depressurizing. Where process requirements demand a quick outlet to
atmosphere, the double barrier shall be obtained by installing two valves in series. If the
effluent will flash and cause sub-zero temperatures, the distance between the two valves
shall be at least 600 mm and the last valve shall be of the spring loaded, self-closing type. The
number of vent and drain connections shall be minimized.
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3.13.4 Drain and vent arrangements are specified in the piping classes and are shown in
PTS 12.30.01. Irrespective of the main piping class / material specification of the vent / drain
valve, the blind flange on down-stream of the gate valve can be carbon steel to ASTM A 105
material specification, provided with bolting & gasket per the respective piping class. This is
based on no galvanic corrosion is expected to take place between the SS / Duplex gate valve
& the CS blind flange, considering there would be no presence of fluid on down-stream of the
vent / drain (NC) valve. [Note: The gasket between the valve and blind flange could be RF
Tanged Insert Graphite].
3.13.5 Vents and drains shall be as short and straight (with no bends) as possible. If long connections
are required (e.g. due to thick insulation on the main pipe &/or due any approach issues),
supports/bracings and/or a larger branch size shall be applied. See Standard Drawing
D12.92.355 (Typical Bracings for Small Bore Branches of Piping, e.g. Drain / Vent Points –
Straight). Where providing straight is not possible due to space constraints in the layout, the
valve can be located horizontal with a 90degree bend, provided with supports / bracings. See
Standard Drawing D12.92.357.
3.13.6 All drain and vent points shall be closed with a blind flange. For vent / drain test connections
in HP and MP steam piping and for other points related to test connection, see Section 3.15
of this PTS.
3.13.7 Drains shall be located so that there is sufficient free space underneath to install temporary
facilities to discharge the drained liquid.
CONNECTIONS FOR MANUAL SAMPLING
3.14.1 Section specifies requirements for manual sampling, not for on-line process stream analyser
connections (for the latter, see PTS 14.30.01).
3.14.2 Dedicated connections shall be provided for sample collection. As a base case the
recommendation is to use Non-retrievable type connection for manual sampling, unless the
Owner specifically ask for Retrievable type.
3.14.3 In case of non-retrievable type the branch fitting connection shall be DN 40 x Rating of flange
to match with the respective piping class x 150mm projection from piping OD to flange face
(RF) as a standard. In case of insulated piping or for any location issues, the projection may
be increased during detail engineering. For details refer to STD.P.0150, as attached and. For
“Flanged-End-Outlet” of 150mm projection, refer to Standard Drawing D12.92.331 (Branch
Fittings), as attached.
3.14.4 In case of retrievable type, the branch fitting connection shall be of flanged type. Flare-weld
type Access Fitting Body is not normally accepted, unless specifically approved by Owner.
The size of branch fitting shall be DN 50 x Rating of flange to match with the respective piping
class x 150mm projection from piping OD to flange face (RF). Refer to S38.090-A. In case of
insulated piping or for any location issues, the projection may be increased during detail
engineering. In case of retrievable type, the piping layout shall include space availability for
using the retrievable tool / service valve for removal / assembly of the sample pipe, and
orientation of the fitting shall be agreed during detail engineering.
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3.14.5 The sampling point shall be positioned so that the valves are easy to operate and taking the
sample will not impair the safety of personnel or plant or cause environmental impact.
3.14.6 The sample shall be maintained in a single phase. The sample take-off shall be at a point
where the gas is at least 10 °C above dew point or the liquid is at least 10 °C below the bubble
point. Good locations for sampling are typically the discharge of pumps and the suction of
compressors.
3.14.7 Samples should be taken from a vertical pipe where possible; where this is not possible:
i.
For gaseous products in horizontal pipes, sample take-off connections shall be
installed at the top of the pipe.
ii.
For liquid products in horizontal pipes, sample take-off connections shall be
installed at the side of the pipe.
3.14.8 Sample take-off connections shall not be located at dead ends of piping.
3.14.9 Sample take-off connections shall be easily accessible and should be at ground level.
However, sample pipes shall be as short as possible as and not longer than 8m.
3.14.10 As far as practicable, sample connections shall be grouped together and provided each with
a sample cabinet which can be connected to one common drain facility.
3.14.11 Wherever possible drain facilities shall be connected to a sample recovery system.
3.14.12 Sample points shall have two valves: one at the take-off point from the process pipe and
another at the sampling point. The block valve at the take-off point shall be “Modular Double
Block & Bleed Sampling Valve” with DN 40 Flanged (RF) connection on one end & with (DN
15) ½” NPTM connection on the other end. The rating of the flange shall match with the
respective piping class of process piping. The DN 15 sampling valve shall have good throttling
properties. If a short sample take-off pipe cannot be fitted, a closed loop shall be provided.
The closed loop shall be a connection to the same process stream, at different pressure. The
loop shall be provided with block valves at the connections with the process pipe.
3.14.13 To avoid freezing or plugging of the sample pipe, e.g. for high-pour-point or viscous fluids,
precautions shall be taken. In cases where freezing or plugging of the sample pipe is not
avoidable, alternatives like:
i.
Using Retrievable type of access fitting or
ii.
To provide piping valves to isolate the process for retrieval and cleaning of the
sampling pipe.
3.14.14 If the outlet of a single sample connection is not connected to a sample cabinet, it shall either
have a male thread and be closed with a threaded cap, or it shall have a quick-fit coupling
which seals when not connected to a sample receiver.
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3.14.15 Sample outlets for fluids above their auto-ignition temperature, for LPG and for very toxic
products shall (PSR) have a self-closing downstream valve. If the effluent could flash and create
sub-zero temperatures, the distance between the two valves shall (PSR) be at least 600 mm.
3.14.16 The following Standard Drawings should be used:
i.
Steam sample device
D12.92.304
ii.
Sample cooler
D12.92.306
iii.
Sample cabinet, carbon steel/low-alloy steel
D12.92.308
iv.
Sample cabinet, stainless steel
D12.92.309
v.
Sampling point assembly
D12.92.351
TEST CONNECTIONS
3.15.1 The location of the connections shall permit the complete removal of the test medium after
the test.
3.15.2 Wherever blind plates or blind flanges cut from plate material for temporary use during
testing period are used, these blind plates / flanges shall be design checked for its dimension
(thickness etc.) based on the test pressure and material specification of the plate, per the
design / testing code. The design allowable stress for this temporary testing stage could be
taken at 90% of Yield Strength, at room (test) temperature.
3.15.3 The supply connection shall be of a size which will allow the system to be filled within a
reasonable time and it shall have a temporary, flanged globe valve which shall also be used
for depressurizing.
3.15.4 Vent flanges for HP and MP steam pipes may be replaced by welded caps after the hydrostatic
test if specifically requested by Owner. All these welds shall be non-destructively examined
to the same standards as the other welds in the system and shall be monitored during initial
operation at operating pressures.
THERMOWELL CONNECTIONS
3.16.1 Flanged thermowells are suitable for run pipe DN 80 and larger and shall be selected as
follows:
ASME rating classes
Thermowell size
Standard Drawing
150, 300, 600 and 900
D12.92.339
1500 (schedule 80 max)
D12.92.339
1500 (schedule 160)
D12.92.340
2500
D12.92.340
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NOTE: DN 50 is selected for thermowell nozzles class 2500 and for class 1500 schedule 160 because the wall thickness does
not allow the thermowell to fit in a DN 40 pipe. However in all cases pipe designer shall ensure the nozzles ID is sufficient for
the thermowell.
3.16.2 The length of flanged thermowells has been standardised as follows:
Thermowell length (mm)
Used for:
230
pipes DN 80 and DN 100
255
pipes DN 150 and larger
305, 355, 405 and 455
equipment (vessels, tanks, etc.)
NOTE: If longer thermowells are required for pipes (e.g. if solidified product on the pipe wall may influence the measurement),
longer thermowells from the equipment range may be applied after the mechanical strength of the thermowell has been
checked with respect to the flow speed and vibration.
3.16.3 On standard drawings D12.92.339 and D12.92.340 a new thermowell design was introduced
in 2001. In the previous design it was possible to install the temperature element without
installing the thermowell, leading to a possibly unsafe situation because the temperature
element is not designed to withstand the pressure of the piping system. In the current design
the cover flange is replaced by a standard lap flange. No modifications to the temperature
element or to the nozzle are required if old standard thermowells are replaced by new
standard thermowells.
3.16.4 The cover flanges of standard drawings D12.92.313 and D12.92.319 were replaced by
standard lap joint flanges.
3.16.5 In pipes with turbulent flow, only thermowells with a length of 230 mm should be used in
order to reduce vibration and forces on the thermowell. In pipes with turbulent flow, the
temperature difference between the centre of the pipe and near the pipe wall is negligible
so the shorter thermowell should not adversely affect the measurement accuracy.
3.16.6 Thermowells should be avoided in pipes with two-phase flow.
3.16.7 Vibrations induced by a von Karman vortex may occur in pipes with high fluid velocities. This
phenomenon is difficult to predict but, in general, special precautions shall be taken for pipes
handling liquids with a velocity above 8 m/s and for pipes handling gases with a velocity above
40 m/s.
NOTE: The values of 8 m/s and 40 m/s are valid for most normal situations. Higher values may be acceptable depending on
pressure and density but this requires special calculations to be performed.
3.16.8 Measures to avoid these vibrations are:
i.
the use of short thermowells
ii.
the use of welded thermowells
iii.
roughening the part of the thermowell exposed to the flow, e.g. by knurling
(standard design)
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iv.
the use of tapered thermowells (standard design)
v.
placing the thermowell at a point with lower fluid velocity
vi.
not installing thermowells downstream of flashing or cavitating valves or other
restrictions where the flow is turbulent
3.16.9 Flanged thermowells shall normally be selected. Welding thermowells according to
D12.92.338 shall only be installed if, due to high velocity and density of the fluid, the bending
loads are too high for flanged thermowells or if they may be subject to vortex induced
vibration (see above).
ORIFICE FLANGES AND ORIFICE METER RUNS
3.17.1 Orifice flanges, raised face, with flange tappings shall be in accordance with standard drawing
D12.92.343.
3.17.2 Orifice flanges, raised face, with corner tappings shall be in accordance with standard drawing
D12.92.344.
3.17.3 Orifice flanges sizes DN 50 up to DN 300 shall be in accordance with PTS 12.30.05.
3.17.4 Orifice meter run sizes DN 15 to DN 40 shall be in accordance with standard drawing
D12.92.346.
3.17.5 Typical bracings for small bore branches of piping (e.g. orifice instrument connection) shall
be in accordance with standard drawing D12.92.356.
3.17.6 Material and components for instrument connections are given in the relevant piping classes.
DISPLACER CHAMBERS
3.18.1 Displacer chambers for displacer type level instruments shall be in accordance with standard
drawing D12.92.317. Loads on equipment nozzles caused by the weight and/or thermal
expansion of displacer chambers shall be checked. To check the thermal expansion forces it
shall be assumed that the equipment is at design temperature and the displacer chamber is
at ambient temperature.
INSTRUMENT PROCESS CONNECTIONS
3.19.1 Connections to piping for pressure instruments shall be in accordance with the piping classes
and basis of design, refer PTS 12.31.01, 12.31.02 and 12.30.01. For PG, PT and PDG, follow
the valve isolation as per para 3.12.1 of this PTS.
3.19.2 Level connections shall be in accordance with PTS 14.10.02. Pressure points shall be as short
as possible. Long connections, if unavoidable, and/or connections to vibrating pipes shall be
properly braced (see Standard Drawings D12.92.355, D12.92.356 and D12.92.357). In both
these cases the pressure gauge block and pressure gauge shall be supported separately.
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THERMAL EXPANSION RELIEF VALVES (TERV)
3.20.1 Thermal expansion relief valves shall be installed in liquid-full equipment or piping systems if
the system can be blocked in and it is subject to heat from the atmosphere or process. See
PTS 16.52.04.
GALVANISED PIPING
3.21.1 Galvanised piping in sizes DN 15 up to DN 50 should be constructed from pre-galvanised
screwed pipe and fittings.
3.21.2 Galvanised piping DN 80 up to DN 100 should be made from pre-fabricated pipe spools. These
spools shall be flanged and shall be restricted to shapes that permit hot dip galvanising after
fabrication. The maximum size of these spools is limited by the available galvanising bath and
by the means of transport.
3.21.3 The application of GRP piping for sizes DN 25 and larger is in most cases the most economic
choice.
CHEMICAL INJECTION CONNECTIONS
3.22.1 For chemical injection requirements, location of connection on the piping to ensure full
mixing, orientation of quill, insertion lengths, and specification refer to PTS 16.52.03 –
Chemical Injection Facilities.
3.22.2 Injection quills and nozzles, typically of proprietary design. Refer to Appendix 7 of PTS
16.52.03 which are of retrievable type.
3.22.3 Unless otherwise specifically requested by Owner, non-retrievable type shall be used. The
non-retrievable chemical injection connections shall be of a “Modular double block (ball
isolation) & bleed (needle vent) injection valve complete with integral check valve and
injection probe” type. The construction will be a one piece forging with integral connection
flange of size DN 40 for connection to the header, DN 15 NPT (F) at the injection end, and DN
15 NPT (F) at the vent end. Depending on the header piping material specification, the
injection valve assembly unit’s material will be usually selected. However as a minimum this
unit shall be of SS316L.
3.22.4 Wherever retrievable types are specifically stated by Owner, to inject into both gas and liquid
lines to ensure uniform dispersion. The nozzle spray characteristics should be a 60 degree
full cone pattern for gas injection and the assembly shall be in accordance with Appendix 7
of PTS 16.52.03. An injection quill does not require these spray characteristics when injecting
into a liquid line. The assembly of injection quill shall be in accordance of Appendix 7 of PTS
16.52.03. When high reliability is required on systems where maintenance is difficult (e.g.
Normally for unmanned facilities), it may be decided not to use a full cone pattern spray
nozzle as per Appendix 7 of PTS 16.52.03 in a gas system, because of the risk of blockage of
the spray nozzle. In these cases an injection quill as in Appendix 7 of PTS 16.52.03 is used.
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3.22.5 For assembly of either retrievable or non-retrievable unit, the main header pipe shall be
provided with a “flange-o-let”, complete with bolting and gasket, as per the header piping
class. In case of dissimilar mating flange assembly, it would be required to install insulating
gasket and sleeves. The projection of the DN 40 flange-o-let (in case of non-retrievable type)
and DN 50 flange-o-let (in case of retrievable type) from the OD of header pipe shall be
controlled and maintained at 150mm.
3.22.6 The injection branch, non-return valve and block valve shall meet the requirements of the
injection line pipe work and the main line in to which the chemical is being injected.
3.22.7 Wherever, retrievable (on-line) chemical injection quills are used, the piping layout along
with the process flow requirements, feasible orientation, required space / access for the use
of “Retriever Tool and Service Valve”, etc. shall be agreed during detail engineering.
CORROSION COUPON (CC) CONNECTIONS
3.23.1 Dedicated connections shall be provided for installation of retrievable corrosion coupon.
3.23.2 The branch fitting connection shall be of flanged type. Flare-weld type Access Fitting Body is
not normally accepted, unless specifically approved by Owner. The size of branch fitting shall
be DN 50 x Rating of flange to match with the respective piping class x 150mm projection
from piping OD to flange face (RF). Refer to standard drawing D12.92.331. In case of
insulated piping or for any location issues, the projection may be increased during detail
engineering. The piping layout shall include space availability for using the retrievable tool /
service valve for removal / assembly of the coupon, and orientation of the fitting shall be
agreed during detail engineering.
CORROSION PROBES CONNECTIONS
3.24.1 Dedicated connections shall be provided for Corrosion Probe Installation. As a base case the
recommendation is to use Non-retrievable type connection for Corrosion Probe Installation,
unless the Owner specifically ask for Retrievable type.
3.24.2 In case of non-retrievable type the branch fitting connection shall be DN 40 x Rating of flange
to match with the respective piping class x 150mm projection from piping OD to flange face
(RF) as a standard. In case of insulated piping or for any location issues, the projection may
be increased during detail engineering. For “Flanged-End-Outlet” of 150mm projection, refer
to Standard Drawing D12.92.331.
3.24.3 In case of retrievable type, the branch fitting connection shall be of flanged type. Flare-weld
type Access Fitting Body is not normally accepted, unless approved by Owner. The size of
branch fitting shall be DN 50 x Rating of flange to match with the respective piping class x
150mm projection from piping OD to flange face (RF). Refer to standard drawing D12.92.331.
In case of insulated piping or for any location issues, the projection may be increased during
detail engineering. In case of retrievable type, the piping layout shall include space
availability for using the retrievable tool / service valve for removal / assembly of the
corrosion probe, and orientation of the fitting shall be agreed during detail engineering.
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SAND PROBE CONNECTIONS
3.25.1 Dedicated connections shall be provided for Sand Probe Installation. As a base case the
recommendation is to use Non-retrievable type connection for Sand Probe Installation,
unless the Owner specifically ask for Retrievable type.
3.25.2 In case of non-retrievable type the branch fitting connection shall be DN 40 x Rating of flange
to match with the respective piping class x 150mm projection from piping OD to flange face
(RF) as a standard. In case of insulated piping or for any location issues, the projection may
be increased during detail engineering. For “Flanged-End-Outlet” of 150mm projection, refer
to Standard Drawing D12.92.331.
3.25.3 In case of retrievable type, the branch fitting connection shall be of flanged type. Flare-weld
type Access Fitting Body is not normally accepted, unless specifically approved by Owner.
The size of branch fitting shall be DN 50 x Rating of flange to match with the respective piping
class x 150mm projection from piping OD to flange face (RF). Refer to standard drawing
D12.92.331. In case of insulated piping or for any location issues, the projection may be
increased during detail engineering. In case of retrievable type, the piping layout shall
include space availability for using the retrievable tool / service valve for removal / assembly
of the sand probe, and orientation of the fitting shall be agreed during detail engineering.
MODIFICATION TO EXISTING PIPING SYSTEM
3.26.1 Where modifications are made to existing piping systems, the following shall apply.
i.
Piping Classes
Where modifications are made to existing piping systems, piping classes for the
modification shall be selected from PTS 12.31.01 and/or PTS 12.31.02 as
applicable. Selection of piping classes shall be in accordance with PTS 12.30.01.
Wherever third party piping classes are used in any existing facilities the use of
PTS Piping Classes shall be determined by the Owner.
ii.
Tie-ins
When connecting into existing piping systems, due consideration shall be taken
of hydrostatic testing requirements. Tie-ins shall preferably be at a flanged
connection with a spectacle blind to enable the new system to be pressure tested
independently from the existing system.
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PIPING ADJACENT TO EQUIPMENT
GENERAL
4.1.1
Piping and pipe supporting structures shall be designed so that access is provided for
maintenance or removal of valves, in-line instruments, tube bundles and shell/channel covers
(e.g. cranes and trucks) and for operational reasons (e.g. filter cleaning). Removal or
replacement of equipment shall be possible with a minimum dismantling of piping.
Removable pipe spools may be required. Small pieces of equipment and ancillaries which
need regular supervision or maintenance should be installed on elevated plinths in order to
improve access.
4.1.2
Drain and vent provisions:
i.
All equipment shall have a valved drain and a valved vent provided
ii.
Equipment and piping containing slurries shall have minimum size DN 25 drain
connections, unless the type of drain valve dictates a larger size (e.g. ram-type
valve)
iii.
Operational drains for equipment and piping containing liquefied petroleum
gases shall be in accordance with PTS 12.20.02
iv.
There is no need for an equipment drain or vent if the equipment can be
adequately drained or vented via connected piping.
4.1.3
For drainage systems see PTS 11.12.03.
4.1.4
At an early stage of detailed engineering, the Contractor shall specify the design nozzle loads
for stationary equipment and the equipment shall be ordered accordingly. In specifying the
nozzle loads, the Contractor shall ensure that they are sufficient for reasonably expected
piping loads but shall not specify them so high that they require unnecessary nozzle
reinforcement. Piping shall be designed such that the specified nozzle loads are not
exceeded. Where possible, the Contractor shall provide more flexibility in the piping rather
than require additional nozzle reinforcement.
4.1.5
If equipment flanges deviate from the standard sizes selected from the piping classes, the
matching pipe flanges shall be ordered with the equipment.
4.1.6
Piping shall be arranged such that the internals of in-line piping items can be removed for
maintenance. Examples are control valve, strainers/filters, flowline chokes, etc.
PUMP, COMPRESSOR AND STEAM TURBINE PIPING
4.2.1
General
i.
Piping at pumps, compressors and steam turbines shall be sufficiently flexible
and adequately supported to prevent the equipment nozzles from being
subjected to any stress that could disturb their alignment or internal clearances
or otherwise affect the equipment and jeopardise its operation.
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4.2.2
ii.
Onshore reciprocating compressors and integral piping should be supported on
a common slab to avoid differences in settlement between the compressor body
and the connected piping. In order to prevent transmission of vibrations to a
compressor house, the support for compressor piping shall be properly designed.
iii.
Excessive vibration of piping connected to reciprocating compressors shall be
avoided. A study shall be carried out according to API 618 to determine the
optimum support location. Results of the study shall be submitted to the Owner
for approval.
iv.
The allowable loads and moments on equipment nozzles shall be in accordance
with the relevant PTS and their associated standards (e.g. API) for the equipment.
v.
The equipment requisitions shall specify whether flanged vent and drain nozzles
are required.
vi.
Auxiliary piping shall be neatly routed along the base-plate and shall not extend
across the operating floor. This piping shall not obstruct inspection covers,
bearing caps, upper halves of casings or any other items which require access for
operation or maintenance.
vii.
In order to avoid a fire hazard, lubricating oil, control oil and seal oil pipes shall
not be routed in the vicinity of hot process or hot utility pipes.
viii.
Cooling water pipes to pumps and compressors shall not be less than DN 20.
Pipes DN 25 or less shall have the take-off connection from the top of the water
main pipe in order to prevent plugging during operation.
Pumps
i.
General
a) For pump selection, testing and installation see PTS 12.11.01.
b) Each individual pump shall be provided with a strainer in the suction
pipe. A block valve shall be installed upstream of the strainer in the
suction pipe of each pump. This position enables the strainer to be
cleaned without draining the complete suction pipe. The piping
components from the suction nozzle up to and including the first block
valve of the pump shall have the same rating as the discharge piping in
order to accommodate overpressure due to backflow from the discharge
side. This also applies to multi-stage pumps.
c) The discharge pipe shall also have a block valve. A check valve shall (PSR)
be installed unless there is no possibility of backflow or pressure surge
under any conditions. This check valve shall (PSR) be installed upstream
of the block valve to enable maintenance of the check valve without
draining the discharge pipe. The liquid volume between the check valve
and the pump discharge block valve shall be as small as practical.
d) Unless the pressure drop would be too high, the discharge valve, suction
strainer and suction valve should be of the same size as the pump
nozzles, for economic reasons and also to minimise the weight of
attachments.
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e) A calculation sheet for pumping data shall be prepared for each pump,
showing calculations for suction and discharge conditions, static
head, static pressure, vapour pressure at pumping temperature and
minimum available NPSH (Net Positive Suction Head), including the
calculated pressure drop in equipment, pipes, valves, fittings and control
valves.
ii.
Valved bypass around discharge check valves of spared pumps
a) For spared pumps which have common suction and discharge pipes, a
bypass with a throttling valve around the discharge check valve allows a
small flow to keep the spare pump at operating temperature, ready for
immediate start-up. It also allows for a controlled warming (or cooling)
of the pump and therefore avoids undesirable thermal effects on pipes
and equipment during this heating (cooling) process. Plugging of spare
pump piping connections will also be avoided. Depending on the pump
type and service, extra flushing connections may be required in the pump
casing to keep it at operating temperature.
b) A bypass shall (PSR) be installed in the following cases:
iii.
-
if discharge and suction pipe operating temperatures are above 150
°C
-
if the pumped fluid can solidify at ambient temperature, e.g. water
pipes in freezing climates
-
if discharge/suction pipe operating temperature is below 10 °C
-
if draining of the space downstream of the check valve is required.
-
for pumps handling highly volatile liquids at pumping temperatures,
e.g. LPG service
Size of valved bypass:
a) DN 20 pipe with a throttling valve shall be used as a standard except as
specified for b) second and third bullet below.
If the discharge and suction pipes have an operating temperature at or
below ambient temperature, instead of installing a bypass around the
check valve it may be considered to have a hole of 3 mm to 5 mm
diameter in the closing member of the check valve. Valves with such a
hole in the closing member shall be marked on the valve body and on
the P&ID and isometric drawings.
b) For systems operating at temperatures above 150 °C, DN 25 pipe with a
throttling valve shall be used in the following cases to ensure sufficient
flow of hot fluid to allow uniform warming of the pump and its suction
and discharge piping:
- for large pumps (suction piping ≥ DN 400)
- if the suction and/or discharge pipe has a length L of more than 25
m (see Figure 1 below)
- If the bypass pipe is schedule 80 or heavier
- for services where severe fouling is expected
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iv.
v.
c) For systems operating at temperatures above 150 °C, DN 40 pipe with a
throttling valve shall be used for pumps with a suction diameter equal to
or greater than DN 600.
The bypass flow depends on the viscosity of the fluid and the pressure difference
between the discharge and suction of the pump. In order to be able to limit the
bypass flow, the bypass arrangement around the check valve shall be designed
so that a restriction orifice can be installed when necessary.
The warming-up flow shall be such that thermal shock in the pump and the piping
is avoided. Depending on the viscosity of the fluid and the pipe size this small
flow will lead to an unequal temperature distribution in horizontal pipe spools.
Temperature differences of more than 200 °C between the top and the bottom
of horizontal DN 400 pipes have been recorded. Heat tracing shall be installed
along pipe sections that become stagnant when the process pump is not
available, i.e. between the block valves and the junction at pump suction and
discharge side, along the valved bypass around the check valve and at the
connection for the pressure gauge. Details are given in Figure 1 below:
Figure 1: Bypass around check valve of spared pumps
vi.
Strainers
a) Permanent strainers shall be installed in all pump suction pipes.
b) Y-type strainers shall be used for permanent installation in vertical
suction pipes. In horizontal suction pipes, Y-type or bucket-type strainers
may be used. Bucket-type strainers shall be used for suction pipes DN
450 and larger. The installation of a Y-type strainer in the suction of
double-suction pumps shall not disturb an even flow to the suction
nozzle of the pump. In a vertical suction pipe the Y-type strainer shall be
installed pointing away from the pump. In a horizontal suction pipe the
Y-type strainer shall be installed pointing downwards or at an angle of
maximum 45° from vertical, in order to improve access for cleaning.
c) For Y-type strainers see Standard Drawing D12.92.301.
d) For bucket type strainers see Standard Drawing D12.92.302.
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e) The design and material for strainers shall be suitable for the process and
pump requirements.
f) Pumps shall be protected at initial start-up by inserting a temporary fine
mesh (40 mesh) screen on the upstream side of the permanent strainer.
g) A spade or spectacle blind shall be inserted downstream of the suction
valve and upstream of the discharge valve to isolate pumps during
maintenance.
h) Collecting and processing facilities shall be used in order to avoid spillage
during withdrawal or replacement of strainers and maintenance of
pumps.
vii.
Venting / flushing
a) Pump vents shall be connected to the vapour space of the suction vessel
for operation under vacuum; this allows the pump to be filled before
start-up. The vent pipe shall have two valves, one at the pump and one
at the vessel.
b) Pump vent and drain nozzles shall be fitted with valves and, if not
connected to a drain system, the valves shall be fitted with blind flanges.
c) Pumps handling butane or lighter process fluids shall (PSR) have a vent
pipe to the flare system. The vent pipe shall (PSR) have a spectacle or
spade blind.
d) Pumps handling cryogenic process fluids shall (PSR) have a vent pipe to the
suction drum. The vent pipe shall (PSR) have a spading point and shall
follow the shortest practical route to the suction drum. The vent pipe
shall have no pockets. This vent pipe shall be large enough to allow the
liquid level to equalise easily with the level in the suction drum without
creating vapour pockets in the pipe.
e) In order to facilitate safe priming of pumps handling hydrocarbons above
their auto-ignition temperature, one of the following piping systems
shall (PSR) be used:
viii.
-
The preferred method is to install (cold) flushing oil supply and
return connections and a bypass around the check valve. This is only
feasible if the pumped product is compatible with the flushing oil. It
may not be a practical solution if no flushing headers are available in
the vicinity.
-
The installation of venting/priming pipes with readily accessible
valves from the highest point in the pump arrangement, i.e. the
casing vent and/or a high point vent in the suction pipe, back to the
suction vessel above the normal liquid level, and a bypass around the
non return valve.
Cooling water supply
Fresh water should be used for cooling. For sea water or other untreated water,
a spared strainer shall be installed in the main cooling water supply header.
ix.
Pressure relief
Positive displacement pumps shall (PSR) be safeguarded against a blocked outlet
with a pressure-relief device. This shall (PSR) not be an integral part of the pump
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and shall be in accordance with PTS 12.11.04. The relief valve shall (PSR) be
installed in a bypass between the discharge pipe upstream of the block valve
and the suction vessel.
x.
Suction piping of centrifugal pumps
a) Suction piping shall be as short and as direct as possible, avoiding high
spots where pockets of gas or air could accumulate. Only eccentric
reducers (top flat) may be used for pipe diameter changes in horizontal
pipes. In vertical pipes, eccentric or concentric reducers may be used.
b) The length of the straight pipe from the last elbow to the suction nozzle
shall be sufficient to ensure minimum turbulence at the pump suction.
The minimum length, which shall not include any reducer, strainer or
stop-flow valve, shall be as stated below:
Type Of Pump
Position Of Suction Piping
Minimum Straight Length
in same plane as pump shaft
1.5 D *
perpendicular to pump shaft
4D
not applicable
4D
at top of pump
4D
in same plane as pump shaft
1.5 D
perpendicular to pump shaft
(preferred situation)
3D
any position other than
perpendicular **
5 D to 10 D
Vertical close-coupled
Single suction,
end suction type
Single suction,
top-top connection
Double suction
* For vertical close coupled pumps with 1.5 D straight length, eccentric reducers (bottom flat) are preferred.
** It shall be studied how unequal flow to the impeller eye can best be avoided. The advice of the pump Manufacturer
should be sought in this respect.
4.2.3
Compressors
i.
To prevent fatigue failure of compressor piping, the effect of vibrations and
pressure surge shall be considered.
ii.
Butt-welding components shall be lined up accurately and weld roots shall be
ground smooth wherever possible. Gas tungsten arc welding (GTAW) should be
used for the root pass of welds. GTAW shall be used for the root pass of welds if
it is not possible to grind the root smooth.
iii.
Inter-stage and discharge piping shall be sufficiently flexible to allow expansion
due to the heat of compression.
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iv.
Block valves shall be installed in the suction and discharge pipes, except for
atmospheric air compressors, which shall have block valves in the discharge pipes
only. The block valve in the suction pipe, if present, and the piping to the suction
nozzle shall have the same rating as the discharge piping.
v.
The ASME rating class of the suction piping, valves and suction pulsation
dampeners (if fitted) of a reciprocating compressor shall have the same rating as
the discharge of that stage.
vi.
Except for reciprocating compressors, compressor discharge pipes shall (PSR) have
a check valve between the block valve and the discharge nozzle as close as
practical to the compressor discharge nozzle.
vii.
In each compressor suction pipe, a temporary start-up suction strainer shall be
installed downstream of the block valve of the compressor and as close as
possible to the compressor suction nozzle. Screens and filters shall be reinforced
to prevent their collapse or failure and subsequent entry of debris into the
compressor, see standard drawing D12.92.310. Provision shall be made to
measure the pressure difference across the strainer in order to monitor fouling.
viii.
Temporary start-up strainers for reciprocating compressors shall be provided
with a 200 mesh start-up screen, while strainers for centrifugal compressors shall
be provided with a 40 mesh to 60 mesh screen.
ix.
To protect against a blocked outlet, reciprocating compressors shall (PSR) have a
pressure-relieving device installed in a bypass between the discharge pipe
upstream of the block valve and the suction vessel. Interstage sections shall (PSR)
also be protected by relief valves, see PTS 12.11.32.
x.
The suction pipe between a knock-out drum and the compressor shall be as short
as practicable, should have no pockets and should slope down towards the
knock-out drum.
xi.
The following straight length requirements apply to compressor inlet and outlet
piping:
Type Of Compressor
Centrifugal compressors, axial
compressors or combinations
thereof and compressors with
interstage side stream inlets
Inlet Opening
Preceded By:
Minimum Straight Length
Before Inlet
Straight pipe
3D
Elbow
3D
Reducer
5D
Valve
10 D
Flow device
5D
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Type Of Compressor
Centrifugal compressors, axial
compressors or combinations
thereof and compressors with
interstage side stream outlets
4.2.4
Outlet Opening
Followed By:
Minimum Straight Length
Before Inlet
Straight pipe
3D
Elbow
3D
Reducer
5D
Valve
5D
Flow device
10 D
xii.
For further information on this subject see ASME PTC-10, section 4.3
xiii.
Flow straightening devices to reduce the required straight length of compressor
inlet piping, such as vaned elbows or other piping internals, may be used only
with the approval of the Owner.
xiv.
If two or more compressors are combined, their suction pipes should enter at the
top of the header, except that suction pipes at least one pipe size smaller than
the header may enter at the side of the header.
xv.
Compressors in hydrocarbon or very toxic service shall (PSR) have purge facilities.
Spading capability shall (PSR) be provided by spectacle blinds, removable spool
pieces or elbows.
Steam turbines
i.
The set pressure of the relief valve in the turbine exhaust system shall not exceed
either the turbine design pressure or the pressure of the exhaust piping,
whichever is the lesser. The relief valve shall (PSR) be installed between the turbine
outlet and the check valve.
ii.
The calculation for the relief valve orifice shall be based on the turbine inlet
nozzle.
iii.
Warming-up facilities shall be provided for the turbine inlet piping and the
turbine.
iv.
Piping shall be designed to permit steam-blowing up to the inlet and outlet
flanges of the turbine before start-up.
v.
Steam vents shall be routed to a safe location and shall (PSR) not be combined with
any lubricating oil, seal oil or process vent.
HEAT EXCHANGER PIPING
4.3.1
Stacked heat exchangers may be either bolted or welded nozzle-to-nozzle. The latter option
eliminates flange leakage but puts restrictions on the maintenance of the exchangers.
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4.3.2
Sufficient space shall be kept between adjacent heat exchanger inlet and outlet valve
manifolds.
4.3.3
Shell and channel box piping shall be provided with vent and drain connections (3.13) unless
it can be vented and drained via other equipment. Drain and vent nozzles on heat exchangers
shall have a valve and a blind flange. The drain and vent connections may also be used for
chemical cleaning, if required.
4.3.4
Collecting and processing facilities shall be used in order to avoid product spillage during
maintenance.
4.3.5
If shell-and-tube exchangers can be blocked in by valves, causing trapped liquid/vapour,
attention shall be paid to:
i.
preventing exposure of the low-pressure side piping to the maximum pressure
of the high-pressure side, regardless of whether caused by internal failure or
otherwise;
ii.
potential increase of pressure difference between the high and low pressure
sided
4.3.6
The danger of overpressurising arises in the event of a tube burst with different design
pressures on the shell and tube side, see API RP 521. The correct design practice for such a
case is outlined in PTS 12.21.01.
4.3.7
Heat exchangers shall (PSR) have a check valve in the steam inlet if the normal steam pressure
is less than 110% of the process relief valve set pressure or, if there is no relief valve, 110%
of the process design pressure. The design shall (PSR) take tube burst into account and shall(PSR)
include facilities to prevent undesirable effects, e.g., back-flow of hydrocarbons into steam
systems, hydrocarbon entry into condensate or water systems, and entry of water into hot
hydrocarbon systems.
FURNACE AND BOILER PIPING
4.4.1
For furnace and boiler piping see also PTS 16.39.02, PTS 12.40.01, and PTS 12.41.01.
PRESSURE VESSEL PIPING
4.5.1
Vertical pipes branching from columns and other vertical vessels shall have a resting support
near the nozzle and shall be guided at regular intervals to protect the pipe against vibrations,
wind load and/or buckling. If the loads on this resting support are too high a spring support
should be positioned at a lower elevation in order to reduce them. For the required flexibility
of the piping, attention shall be paid to the location of the lowest guiding support.
4.5.2
Pipe supports on pressure vessels shall be bolted to cleats welded to the vessel. Cleats shall
be designed by the Contractor and form an integral part of the pressure vessel. Where
practical, cleats shall be standardized. Cleats and the connected pipe supports and/or
supporting steel shall be designed so that there will be no ingress of water under the
insulation.
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4.5.3
To allow removal of covers, heads, channels, bundles and shells, pipes shall not be supported
on heat exchanger shells or heads. To satisfy vapour disengagement requirements for liquid
pipes from draw-off trays in columns, there shall be at least 1500 mm from the draw-off
flange down to the reducer. This 1500 mm also applies if more than one liquid draw-off nozzle
is connected via an equal tee.
4.5.4
A tall, slender vessel (L/D ≥ 10) may be susceptible to aerodynamic excitations, and piping,
platforms and ladders at the top third of the vessel should be located so that they will act as
aerodynamic stabilisers and reduce cross-wind vibrations.
4.5.5
Where practical, pressure vessels which are grouped together shall have platforms and
interconnecting walkways at the same elevation. The number of stairways and ladders to the
platforms shall be sufficient to meet safety requirements. Where practical, pressure vessels
grouped together shall have their level gauges at a common level.
4.5.6
If not controlled in some other way, process steam pipes to pressure vessels shall have a
regulating globe valve fitted at the pressure vessel nozzle. To prevent the product from
entering the steam pipe, a check valve shall (PSR) be installed close to and upstream of the
regulating valve with a low point drain (with valve) between them. A gate valve shall be
installed upstream of the check valve to isolate the pipe from the main steam header.
4.5.7
The DN 50 utility connections shall not be connected permanently to the steam header. The
pressure vessel nozzle shall have a valve with blind flange. The valve, bolts and gaskets shall
satisfy the requirements of both the utility and the process conditions. For ASME rating
classes of 900 and higher only a blind flange shall be used.
4.5.8
The steaming-out pressure for columns should be 3.5 bar (ga), except that a higher pressure
may be considered for tall columns if the design permits.
4.5.9
Pressure vessels shall have a drain, either on the bottom outlet pipe or at the lowest point of
the vessel. The drain valve shall be outside the skirt. The size of the drain shall be at least DN
50.
4.5.10 Drain pipes for pressure vessels shall be sized to empty the vessel volume, or the volume
below a column bottom tray, by gravity within two hours.
4.5.11 Large transfer pipes from furnaces should have welded instead of flanged connections to
columns in order to avoid leakage. In those cases, the spade or spectacle blind shall be located
at the furnace side of the transfer pipe, where the diameter is normally smaller.
RELIEF SYSTEMS
4.6.1
Pressure-relief systems shall be in accordance with PTS 16.52.04.
LEVEL GAUGES
4.7.1
General
Conventional level gauges are relatively weak and vulnerable. For equipment containing
hydrocarbons or very toxic fluids, the possibility shall be considered early in the design
stage of eliminating level gauges where they are not essential for the safe operation of the
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facilities. If level gauges are essential in these services, the installation of blow-out
preventers (excess flow valves) on the isolating valves between the equipment and the level
gauge should be considered. Blow-out preventers are more likely to remain effective when
applied in clean product service. Where level gauges are essential but blow-out preventers
cannot be used in fouling services, high integrity level indicators of the magnetic type shall
be installed. Alternatively, multiple level transmitters (where one transmitter provides a
local reading) may be fitted.
4.7.2
Level gauges
i.
Magnetic-type level gauges have high integrity due to their enclosed
construction. Long magnetic-type level gauges are available which eliminate the
need for multiple level gauges. Magnetic-type level gauges shall be of the
magnetic-coupled level indicator type. Each level gauge shall have a DN 20
flanged vent and drain connection, each with isolation valve and blind. The
following points shall be taken into account if magnetic type level gauges are
applied:
a) if a stainless steel flange is fitted into a carbon steel system, the flange
shall have a suitable rating (the mechanical strength of stainless steel is
lower)
b) the specific gravity of the fluid to be measured shall be specified by the
Owner
c) pressurized floats shall not be used
d) flanged vent and drain connections shall be provided
e) floats shall be bottom-inserted (top-mounted floats can become
damaged or stick in the bottom)
f) a bottom float stop (e.g. a spring) shall be provided;
g) bottom housings shall not be conical (to prevent the float from sticking)
h) level gauges shall be shipped without the floats installed
i) floats shall be installed after hydrostatic pressure testing
j) the housing shall be designed so that no moisture or dirt can enter (e.g.
filled with inert gas and hermetically sealed)
k) the level gauge shall be located so that there is sufficient space for
maintenance
ii.
Plate-type level gauges (refer to Standard Drawing D12.92.318) have standard
center-to-center nozzle distances of 450 mm, 840 mm and 1230 mm. Plate-type
level gauges shall be restricted to ASME rating classes 150, 300 and 600 and the
design temperature shall not exceed 265 °C. Reflex-type level gauges without
lighting shall be used wherever possible. Through-vision type level gauges with
lighting shall only be used for adhesive liquids which give unclear readings on
reflex-type level gauges (i.e. where a liquid film remains after the level has
dropped).
iii.
Collar-type level gauges (refer to Standard Drawings D12.92.316 and
D12.92.320). These level gauges may be used only up to a design pressure of 10
bar (g) and a design temperature of 130 °C. Tracing tubes are optional.
iv.
Bull’s-eye level gauges, may be used only in ASME rating classes 900# and 1500#.
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v.
4.7.3
Wall-type gauge glass (refer to Standard drawing D12.92.009). Wall-type gauge
glasses may be used only up to a design pressure of 41 bar (ga) and a design
temperature of 300 °C. Reflex type gauge glass shall be used for indicating the
interface between two liquids. Transparent glass shall be used for indicating the
interface between liquid and gas or vapour.
Installation of level gauges
i.
General
a) The span of a level gauge shall cover the required operating range and
the entire range of other level instruments, see Appendix 8.
b) If the required level range is too large for a single gauge, multiple level
gauges shall be used, with the connection nozzles staggered for a visible
overlap of at least 25 mm.
NOTE: Long magnetic-type level gauges are available which obviate the need for multiple level
gauges.
c) If the visible level range in a gauge is continued in a second (staggered)
level gauge, or the level is used to check another level instrument, both
levels shall be readable from the same location.
d) The pressure and temperature rating of the level gauge shall be same as
the pressure and temperature rating of the vessel.
e) To ensure clear visual access for the operator, level gauges shall not be
placed behind pipes or other obstacles. The level gauge shall be
positioned so that it can be read from ground level, platforms or ladders.
f) Sufficient clearance shall be provided if illuminators are to be installed
on level gauges.
g) If a light is needed to read the level gauge, the level gauge shall be less
than 1m away from where the operator is standing. If this is not possible
an illuminator shall be installed behind the level gauge.
h) If a level gauge has to be heated, the heating element shall be external.
i) All requirements shall be specified on the data sheet for level gauges and
the requisition sheet for level gauges.
j) Drain valves on level gauges shall be accessible.
ii.
Connections
a) Flange pairs of level gauges shall be aligned within the tolerances
specified in PTS 12.20.01, as applicable.
b) Double block valves shall (PSR) be fitted in ASME rating classes 600 and
above for hydrogen services, and ASME rating classes 900 and above for
other services. For double block arrangement of upstream facilities, see
section 3.12.1.6.
c) Level gauges shall (PSR) be connected with block valves between them and
the equipment.
d) All level instrument connections (Level Gauges, Level Transmitters) shall
be directly taken from the related equipment. Each instrument process
connection shall be of size DN 50, provided with a dedicated process
isolation valve. For connection from Standpipe may refer to PTS
14.10.02.
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e) The use of stand pipes in level applications requires approval by the
Owner, since it may introduce systematic measurement errors as a result
of density variations. The decision whether or not standpipes are
allowed to be used needs to be taken in early project stage, as it might
affect equipment design also. Use of stand pipes shall only be allowed,
for specific reasons like a) The equipment is too small to accommodate
more number of level instrument nozzles; b) the fluid is waxy where it
may require frequent cleaning of the hook-up piping, during operation.
f)
If approval by Owner is given for using Standpipe, the configuration shall
be as below:
iii.
If there are more than two pairs of level connections, one or more stand pipes
shall be used. Stand pipes shall satisfy the specifications of the relevant piping
class. The minimum diameter of a stand pipe shall be DN 80. The stand pipe shall
be vertical. The equipment nozzle size shall match this requirement. There shall
be block valve between the stand pipe and the equipment nozzle. There shall
also be block valves for isolation between each level instrument and the stand
pipe. The stand pipe shall be provided with low point drain valve and high point
vent valve with blind flanges c/w bolting and gaskets. Size of drain / vent valves
shall be minimum DN 20, to be decided during process design. Loads on
equipment nozzles, caused by the weight and/or thermal expansion of stand
pipes with level gauges or by magnetic type level gauges, shall be checked. To
check the thermal expansion forces it shall be assumed that the equipment is at
design temperature and the stand pipe or magnetic type level gauge is at
ambient temperature.
iv.
Loads on equipment nozzles, caused by the weight and/or thermal expansion of
stand pipes with level gauges or by magnetic type level gauges, shall be checked.
To check the thermal expansion forces it shall be assumed that the equipment is
at design temperature and the stand pipe or magnetic type level gauge is at
ambient temperature.
INSTRUMENTATION
4.8.1
In-line instruments shall be mounted in accordance with PTS 14.10.02. Instrument impulse
pipes shall comply with PTS 14.10.06.
4.8.2
The design and material selection of in-line instruments and control valves shall satisfy the
pressure and temperature rating of the relevant piping class.
PACKAGED EQUIPMENT PIPING
The extent to which packaged equipment shall meet this PTS shall be defined by the
Contractor and shall be subject to the approval of the Owner prior to placement of order.
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PIG LAUNCHER AND RECEIVER PIPING
4.10.1 Piping upstream of pig launchers and downstream of pig receivers shall be in accordance with
this PTS.
4.10.2 The break-line of specifications shall be shown on the P&ID.
SLUG-CATCHER PIPING
4.11.1 Piping downstream of slug catchers shall be in accordance with this PTS.
4.11.2 The break-line of specifications shall be shown on the P&ID.
VESSEL TRIM
4.12.1 The correct piping class for vessel trim components shall be derived from the equipment data
shown on the P&ID.
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UTILITY PIPING
FIRE WATER
5.1.1
Fire water piping systems shall comply with PTS 16.54.01.
COOLING WATER
5.2.1
Cooling water pipes ≤ DN 600 should have block valves at the plot limit so that they can be
isolated for maintenance while the cooling water system remains in operation.
5.2.2
The Owner shall specify whether plot limit block valves are required for cooling water pipes
larger than DN 600.
5.2.3
Cement-lined pipes DN 900 and larger shall be provided with inspection and maintenance
manholes of minimum size DN 600. The distance between manholes should be no more than
100 m.
5.2.4
Cooling water pipes longer than 100 m shall be checked for potential surges (refer to
Appendix 1).
5.2.5
Large cooling water pipes may require special supports to avoid subsidence.
5.2.6
The possibility should be considered of measuring and recording the flow for each unit or
group of integrated units. Alternatively the plot limit block valves should be of the calibrated
type, i.e. with pressure tappings which enable off-line flow measurement.
5.2.7
Sufficient pressure indicators shall be installed to determine the system pressure profile.
5.2.8
A slight over-pressure shall be maintained in cooling water systems, e.g. by means of a
restriction orifice or an overflow system, in order to avoid vapour locks.
5.2.9
The open funnel pipe to the drain system shall have an extra capacity of at least 20%.
5.2.10 Where sub-zero temperatures may occur a closed cooling water system shall have a bypass
with a globe valve around the upstream and downstream block valves for each unit or
integrated group. Sufficient drain capacity shall be provided.
5.2.11 Cooling towers shall have isolation valves at the inlet to each cooling tower cell to allow
access for maintenance.
5.2.12 If cooling water pipes may be subject to fouling the tie-off shall be taken from the top of the
header in order to avoid fouling of piping and equipment. For cooling water design fouling
data, see PTS 16.12.01.
5.2.13 Main distribution pipes shall have facilities at the lowest points to permit complete draining
within 6 hours. Venting facilities shall be provided to relieve air pockets.
5.2.14 The piping materials shall be selected from the applicable piping classes in consultation with
a materials and corrosion engineer.
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5.2.15 Glass reinforced unsaturated polyester (GRUP) should be used for cooling water pipes unless
uneconomical. Particular advantages of GRUP pipes are corrosion resistance, lower fluid
friction factors and lower susceptibility to fouling.
5.2.16 If economical, concrete pipe or channels may be used for atmospheric pressure cooling water
return pipes.
WATER FOR OTHER PURPOSES
5.3.1
A clear distinction between potable water (water of drinking water purity), industrial water
and various kinds of cooling water, etc. shall be made.
5.3.2
Wherever reasonable, non-metallic piping (8.2.2) shall be utilised for potable and industrial
water.
5.3.3
For reasons which could pollute the potable water system due to back-flow, direct
connections to the potable water system shall not be made. Potable water connections to
process equipment and piping shall pass through a break tank with a siphon breaker.
5.3.4
The connections of industrial water pipes to equipment or piping shall have a check valve and
a block valve. It shall not be permanently connected to process equipment or piping. If a
direct connection is fitted it shall normally be spaded off.
5.3.5
Water pipes which are exposed to freezing, even for a short duration, shall be protected as
follows:
i.
pipes with intermittent flow shall be buried (3.4.1) or protected by heating or
insulation
ii.
closed cooling water systems may be protected against freezing by adding an
antifreeze such as glycol
5.3.6
Water hose connections shall be located so that any required location can be reached with a
15 m long hose.
5.3.7
Potable water to hose stations shall be taken only from the water system downstream of a
break tank.
5.3.8
Hose stations shall have a valve, a connection of the quick-coupling type, a 15 m water hose
and a hose rack.
5.3.9
If the hose is coupled to process equipment or piping, a check valve shall be included.
STEAM
5.4.1
Piping in steam service shall be arranged so that condensate accumulation is avoided.
5.4.2
Stagnant and reverse-flow conditions shall be avoided in steam distribution systems.
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5.4.3
Pipes to consumers shall branch off from the top of the steam supply pipe in order to prevent
condensate from going to the steam consumers, unless the condensate is required to drain
from the steam supply pipe into a steam trap before the steam is passed to the consumer, in
which case they shall branch off from the bottom of the steam supply pipe.
5.4.4
Exhaust steam pipes shall enter at the top of the exhaust collecting pipe to prevent
condensate from running back into neighbouring steam consumers.
5.4.5
Steam pipes shall (PSR) have a block valve at the boundary of the process unit. Flanges shall be
provided at these locations to allow for spading (spades or spectacle blinds) to isolate the
steam systems during maintenance of the unit. Instrument connections for flow, pressure
and temperature measurements shall be installed downstream of the block valves to the
plant or unit.
5.4.6
Steam pipes connected to process pipes shall (PSR) be fitted with a block valve. A check valve
shall (PSR) be installed upstream of the block valve, with a bleeder in between them. The block
valve and check valve shall be close together and close to the process pipe.
5.4.7
Vent facilities of sufficient capacity shall be installed to enable the pipes to be warmed up
prior to commissioning.
5.4.8
All steam pipes shall have drain facilities at the low points and at the end to remove
condensate (e.g. during commissioning).
5.4.9
Steam traps shall be installed at low points or at natural drainage points, e.g. in front of risers,
expansion loops, changes of direction, (closed) valves and regulators. In saturated steam
service, steam traps shall be fitted to drain-pockets. Steam traps shall also be installed at
superheated steam lines to remove condensate during start-up, shutdown, precommissioning and commissioning activities.
5.4.10 Steam traps shall be as near as possible to the condensate outlet of the equipment or piping
to be drained, unless a cooling leg is required.
5.4.11 Steam traps shall have a bypass arrangement if the downtime needed to replace or repair
them would cause a process problem.
5.4.12 Steam traps up to and including DN 40 should be welded and should have removable
internals to allow repair without performing hot work.
5.4.13 Steam traps shall be positioned so that they are easy to maintain and replace. The connecting
piping up to and including the first downstream block valve shall be designed for the full
steam pressure and temperature. Steam traps inside buildings shall have a bypass and shall
not discharge into an open drain inside the building. Block valves and bypass valves up to and
including DN 40 should be welded and have welded bonnets.
5.4.14 Open steam trap discharges shall be located away from doors, windows and air intakes. In
cold areas, icing-up of personnel access areas shall be prevented.
5.4.15 Steam pipes shall not discharge condensate into sewer systems but instead shall run to a safe
location such as collecting condensate pits, accidentally-contaminated water rundown
systems, gravel pits, gullies, etc., and shall be combined as far as practical.
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5.4.16 For steam services, valves DN 150 and larger in ASME rating class 600 and higher shall have
a bypass valve for preheating and pressure-balancing. The bypass size shall be as follows:
BYPASS VALVE,
nominal size, DN
MAIN VALVE,
nominal size, DN
For warming-up of pipe and
for pressure-balancing of
pipes with limited volumes
For pressure-balancing of
other pipes
150
20
25
200
20
40
250
25
40
300
25
50
350
25
50
400
25
80
450
25
80
500
25
80
600
25
100
5.4.17 For steam trap design selection and installation shall refer to PTS 12.32.04.
CONDENSATE
5.5.1
Non-contaminated steam condensate shall be returned to a clean condensate collecting
system. Clean condensate should be treated in a condensate polisher prior to its use as boiler
feed water. Recycling without treatment is subject to the approval of the Owner.
5.5.2
Contaminated steam condensate, e.g. from process heat exchangers, shall be routed to the
contaminated water system or shall be treated and returned to the boiler feed water system.
For precautions to prevent contamination, see (4.3). Equipment producing condensate shall
have a full capacity drain to the contaminated water rundown system.
5.5.3
Contaminated condensate from consumers shall be cooled to ambient temperature before it
is discharged into surface water sewer systems.
5.5.4
Condensate pipes in areas where frost can occur shall be provided with protective heating or
insulation.
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INSTRUMENT AIR
Instrument air supply piping shall be in accordance with PTS 16.39.07. The piping materials
shall be selected from the applicable piping class.
TOOL AIR
For tool air requirements, see PTS 16.39.07. The piping materials shall be selected from the
applicable piping class.
UTILITY HOSE STATIONS
5.8.1
The utilities required shall be specified by the Owner. Where utility hose stations are specified
they should be located so that all points of use in the area can be reached by 15 m long hoses.
Each type of utility medium shall be provided with a dedicated type of hose connection to
prevent contamination and inadvertent connection to the wrong utility medium.
5.8.2
Utility pipes to the manifolds shall branch off from supply headers which cannot contain
contamination, e.g. due to leaking heat exchangers, etc.
5.8.3
Utility station connection piping shall be equipped with a block valve and quick release
coupling.
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TANK FARM PIPING
GENERAL
6.1.1
Within the bunded area the number of pipes shall be minimised and they shall be routed in
the shortest practicable way from the tank to the bundwall. Where practical, the pipes shall
be grouped together.
6.1.2
Pipes connected to tanks shall be sufficiently flexible to cope with thermal
expansion/contraction, tank settlement, the outward movement of the shell and the
inclination of nozzles under hydrostatic load. See PTS 12.22.01. The first pipe support shall
be located sufficiently far away from the tank to allow for tank settlement and the thermal
expansion of the vertical pipe leg. If tank settlement above an acceptable limit is expected,
precautions shall be taken to cope with this settlement (e.g. by using loops or expansion
joints).However expansion joints should be considered as a last resort in absence of other
options. The distance between tank and first pipe support shall be determined by Pipe Stress
Analysis. The following distances may be used as a guidelines.
Nominal pipe size DN
Distance between tank
and first support (m)
100 and smaller
5
150
6
200
7
250
8
300
9
350
10
400
10
450
10
500 and larger
12
6.1.3
For tank pipes of DN 500 and larger, spring or balanced supports may be considered. Piping
shall be connected and supported after hydrostatic testing of the tank. Piping in tank farms
shall be supported by concrete sleepers or steel frames. If relatively small-bore pipes are
installed along with bigger pipes in tank pits having a concrete floor (e.g. in chemical plants),
steel frame supports may be used as intermediate supports between concrete sleepers.
6.1.4
There shall be access to manholes, mixing nozzles, drains and other facilities on the tanks.
Small bore utility piping required for more than one tank may be routed along an
interconnecting overhead walkway, if available.
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6.1.5
Manifolds shall be located outside the bundwall in a concrete paved curbed area which shall
slope and shall be provided with a drain sump at the low side connected to an accidentally
oil contaminated (AOC) drainage system. The outlet shall be provided with a valve for
maintenance purposes.
6.1.6
Tank nozzles, including product drains and water draw-off connections, shall have block
valves. Drains for cleaning purposes only shall be blinded off. The water drain shall be
connected via a closed piping system to the water treating facilities. The product drain valve
shall be blanked off. Provisions shall be made for a piping connection from the product drain
valve to the product drain collection system.
6.1.7
Pipes may only be routed through bund walls if they cannot be passed over such walls (e.g.
suction pipes). For bundwall crossings, see Standard Drawing D11.92.004.
PIPING CONNECTIONS
6.2.1
Piping shall be connected after hydrostatic testing of the tank. Tank settlement, outward
movement of the shell and nozzle inclination under full liquid load conditions shall be taken
into account when calculating bending moments and forces on tank nozzles.
6.2.2
The provision of thermal relief valves shall be in accordance with PTS 16.52.04. In general the
following additional guidelines should be adopted regarding the necessity for the installation
of thermal relief valves.
i.
Unless it can be clearly demonstrated by calculation or previous adverse
operational experience TERVs shall not be fitted to piping rated ANSI/ASME class
600 and higher.
ii.
The piping concerned must be completely filled with single phase fluid, it must
be capable of being blocked under normal operating conditions and it must be
subject to temperature increases caused by process or environmental variations.
iii.
TERV’s need not be installed on offshore piping system as, in general, piping are
not single phase, they are of low volume and rarely left blocked in for extended
periods. They are typically protected by relief valves on associated pressure
vessels.
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PIPING FOR LOADING AND UNLOADING FACILITIES ON JETTIES
GENERAL
7.1.1
The loading and unloading pipes for the different products to or from a jetty are normally
connected to headers located at the end of the jetty.
7.1.2
Connecting pipes between the loading arms and the headers shall slope down to the headers
for drainage.
7.1.3
Where practical, the loading and unloading pipes shall slope down towards the shore for
drainage.
7.1.4
Headers shall have flushing/washing provisions to prevent contamination when different
products are loaded or unloaded consecutively.
7.1.5
Sample connections should be considered for all headers.
7.1.6
Piping on jetties shall be minimum DN 50, except for instrument, drain, vent and sample
connections.
7.1.7
Positive displacement flow meters, and their filters and deaerators, shall be accessible for
operation and maintenance. The deaerator outlet shall have a flame arrester.
7.1.8
For details on flow meters for loading and unloading facilities see PTS 14.10.02.
7.1.9
Piping reaction forces on the loading arm flange shall be minimised. For analysis and surge
calculations, see Appendix 1.
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PIPING COMPONENTS
GENERAL
8.1.1
Components shall be selected from the applicable piping classes. The Owner’s approval is
required for the use of any other components or alternative materials.
8.1.2
Piping systems connected to other systems or equipment with a higher design rating shall
have the higher rating for all components up to and including the first block valve in the
system of lower rating.
PIPE
8.2.1
Metallic pipe
i.
For metallic pipe, reference is made to ASME B31.3
ii.
Metallic pipe shall be in accordance with ASME B36.10 or ASME B36.19.
iii.
The corrosion allowance for carbon steel and ferritic alloy steel pipes shall be at
least 1 mm. For upstream facilities process piping, the minimum corrosion
allowance for carbon steel and ferritic alloy steel pipes shall be 3 mm.
iv.
Field fit allowances
The following additional lengths shall be provided as a fitting allowance at all field
welds.
a) General spools +150mm
b) Wellhead flowline spools +300mm
c) Interdeck/ Intermodule connecting spools +1000mm
8.2.2
Non-metallic pipe
For the thermoplastic and GRP piping, refer to PTS 12.34.04 and PTS 12.34.02 respectively.
8.2.3
Lined piping
i.
Nominal sizes
Nominal sizes of lined piping shall be in accordance with ASME B36.10 or
ASME B36.19 unless otherwise specified.
ii.
Plastic-lined piping
Plastic-lined piping shall be in accordance with ASTM F 1545, except that
welding neck flanges are also allowed. Threaded flanges shall not be used.
iii.
Rubber-lined piping
Rubber-lined piping shall be in accordance with PTS 15.20.07.
iv.
Glass-lined piping
Glass-lined piping shall be in accordance with PTS 15.20.10.
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v.
Cement-lined piping
Cement-lined piping shall be in accordance with PTS 15.20.04
PIPE JOINTS
8.3.1
Metallic Piping
i.
Welded joints
a) Shop and field fabrication of steel piping shall be in accordance with
PTS 12.30.05.
b) Preparation shall be in accordance with ASME B16.25. Permanent
backing rings shall not be used.
c) Welds requiring post weld heat treatment (PWHT) shall be prefabricated
as far as possible, thereby minimising the number of field welds.
d) Wherever welds are to be PWHT, the acceptance of NDT for the welds
shall be after the PWHT.
ii.
Socket welding
a) Selection
The piping classes in PTS 12.31.01 and PTS 12.31.02 are standardized on
butt welding, not socket welding, components.
b) Socket-welded construction shall not be used in the following services:
 services in which crevice corrosion can occur
 ASME rating class above 900
 lower design temperature below 0 °C
 very toxic service
 hydrogen service
 Cyclic service
c) For other services, socket-welded construction is permitted in metallic
piping systems if economically justified. Economic assessment should
take account of the fact that more welds are required in socket-welded
systems because socket-welding components cannot be welded directly
to each other. Typically, there are 25 % more welds in a socket-welded
system than in an equivalent butt-welded system.
d) Vendor’s package units often include socket-welded small bore piping as
a standard. Departing from that standard may have a significant cost
impact. In these package units, socket-welded construction may be
considered acceptable except where defined above.
iii.
Application
SMAW (shielded metal arc welding) and GTAW (Gas Tungsten Arc Welding) are
the commonly applied in piping welding processes.
GMAW (Gas Metal Arc Welding) and FCAW (Flux Cored Arc Welding) shall not be
used.
In order to avoid excessive shrinkage stresses during weld solidification a 1.5 mm
gap shall be left between the end of the pipe and the stop of the socket-welding
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component before welding. Failure to ensure this gap can lead to premature
piping failures.
iv.
Socket-welded connections cannot be properly radiographed to verify weld
quality; they can only be inspected by surface techniques such as magnetic
particle or liquid penetrant. Radiography may be selectively applied to check that
a fit-up gap remains after the weld has been made. For inspection requirements,
see PTS 12.30.05.
v.
Un-listed Piping component
Un-listed piping components as defined in 302.2.3 of ASME B31.3 such as Clamp
type connection joint may be used as an alternative permanent pipe jointing
method subject to approval of Owner. The un-listed piping component may be
used subject to approval of the followings documents during detailed
engineering stage:
a) Design calculation which has been approved by reputable third party
agency. This needs to be supported with FEA report.
b) Proof test record (witness and approved by Third Party Inspection
agency) in accordance with either ASME B16.9, MSS SP-97, or Section
VIII, Division 1, UG-101.
c) Dimensional drawing for each size and rating of the un-listed component,
along with its bill of materials.
d) The clamp and hub shall be of the same material to avoid any
dissimilarity in the mating components and any galvanic corrosion due
to external environmental condition.
e) Details of surface preparation, painting and coating of the un-listed
component i.e. for inner and outer surface of the un-listed component
and outer surface of bolting and hub. The coating and painting shall
comply with PTS 15.20.03.
f) Maximum allowed corrosion of the unlisted component in its designed
life (in present service condition) requires to be estimated to
determining minimum remaining thickness for its integrity considering
no opening of the clamp.
g) Procedure for Online inspection, surface protection and maintenance/
repair during shut down.
h) Clamp type connection shall not be used at piping components that
operates under cyclic conditions e.g. control valve, choke valve, etc.
v.
8.3.2
Other non-welded jointing method such as pre-strained fittings may be used
subject to compliance of applicable requirements mentioned in para (i) above
and Appendix 16.
Gaskets and packing
i.
Compressed Asbestos Fibre (CAF) and Man Made Mineral Fibres (MMMF) shall
not be used.
ii.
The gasket selection shall be based on piping class requirements. For uniformity,
and to prevent mistakes, all nozzles on a piece of equipment should be provided
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with the same type of gasket. The most stringent design condition shall
determine the required gasket.
iii.
If graphite-based materials cannot be used, e.g. for product contamination
reasons, PTFE-based materials shall be applied up to a maximum temperature of
200 °C.
iv.
Flat sheet gaskets
a) Graphite tanged insert gaskets shall be used instead of compressed
asbestos fibre (CAF) gaskets. Where a flat face flange is required, the
counter-flange shall also have a flat face and full face gaskets shall be
applied.
v.
Spiral wound gaskets
a) Spiral wound AISI 316(L) graphite-filled gaskets shall be used instead of
spiral wound asbestos-filled gaskets. Spiral wound gaskets with outer
and inner rings shall be used for all ratings as specified in the piping
classes
b) Spiral wound Monel 400 graphite-filled gaskets may be used up to a
design temperature of 400 °C.
c) Spiral wound Inconel 600 graphite-filled gaskets may be used up to a
design temperature of 650 °C.
d) Spiral wound gaskets shall have a colour code in accordance with ASME
B16.20.
vi.
Metal grooved gaskets
e) For flanged connections above DN 600, and for equipment shell flanges,
metal grooved AISI-316(L)/graphite gaskets with a “lateral” profile height
shall be selected. Metal grooved gaskets with a convex profile shall only
be used in special cases, e.g. if metal grooved gaskets with a lateral
profile cannot provide an adequate seal (e.g. in weak flanges or where
the flange facing is not perpendicular to the design plane). Metal
grooved gaskets with a convex profile may be used only if approved by
the Owner.
vii.
Packing
For the selection of the stuffing box packing and clearances and body/bonnet
gaskets, reference is made to PMRC MAR GS/109, and respective valve’s
specification.
8.3.3
Installation of gaskets
The pressure over the gasket shall be uniformly distributed in order to achieve satisfactory
sealing. To accomplish this, the bolts shall be tightened in accordance with PTS 12.00.06.
Gaskets shall never be re-used, since not enough resilience is left in the gasket material to
give a leak-proof joint when compressed a second time.
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8.3.4
Selection and installation of bolting materials
The design temperatures for the listed bolting material combinations in relation to the
applied piping material shall be as follows:
Piping material
Bolt material
[ASTM
designation]
Nut material
[ASTM
designation]
Allowable design
temperature
range [°C]
Diameter range
[inch]
Carbon steel
Low alloy steel
Stainless steel
Duplex stainless
Steel
Non-ferrous
metal
Non-metal
A193-B7
A194-2H
-40
to
400
½
d
4
Carbon steel
(high sour)
A193-B7M
A194-2HM
-48
to
400
½
d
4
Carbon steel LT
Stainless steel
Duplex st. steel
Super duplex st.
steel
Non-ferrous
metal
A320-L7
A320-L43
A194-4
A194-4
-101
-101
to
to
343
343
½
 2½
d
2½
4
Carbon steel LT
(high sour)
Stainless steel
Duplex stainless
steel
A320-L7M 3)
A194-7M
-73
to
343
½
d
4
Low alloy steel
A193-B16
A194-4
-29
to
480
½
d
4
Low alloy steel
20CrMoVTiB4-10
20CrMoVTiB4-10
-20
to
550
½
d
4
Stainless steel
A453-660 class C
A453-660 class C
-29
to
538
½
d
3½
Stainless steel LT
A193-B8 class 2
A193-B8M2 class
2B
A194-8
A194-8
-200
-200
to
to
300
300
½
 1½
d
1½
3
NOTES:
1. According to ASME B31.3, for externally-insulated flange connections the maximum design temperature may be equal to the
above maximum bolting temperatures.
2. According to ASME B31.3, for non-insulated components with fluid temperatures 65 °C and above the bolting temperature
shall be taken to be not be less than 80% of the fluid temperature.
3. Stud bolts to ASTM A320-L7M with sizes over 2½ inch can be supplied with guaranteed mechanical properties as referenced
in ASME B31.3.
Unless specifically stated in the project specification all flange stud bolts, nuts and pipe
support “U”-bolts shall be fluorocarbon coated for corrosion protection
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8.3.5
Threaded joints
Threaded joints shall not be used in any piping system handling flammable or toxic fluid.
Screwed fittings may be utilised for non-hazardous utilities piping in sizes DN 100 and below
for class rating 150#.
For instrument air package piping, refer to PTS 12.11.34.
Threaded steam traps may be used if it is located downstream of a piping valve.
Threaded joints may be used only in galvanised piping (e.g. for fire water systems) DN 100
and smaller. The minimum wall thickness for these shall be Schedule 80.
Seal welding of threaded connections shall not be permitted.
Threaded joints (where permitted above) shall be NPT pipe threads in accordance with ASME
B1.20.1.
FITTINGS
8.4.1
Fittings shall be in accordance with ASME B16.5, ASME B16.9, ASME B16.24 or ASME B16.47,
as applicable for the type of fitting. Flange design in accordance with API 6A may be used for
wellhead connection.
8.4.2
Reducing elbows, straight crosses and reducing outlet crosses are regarded as special fittings
and should be avoided.
8.4.3
Pipe bending
Bending may be an economic alternative to welding elbows for changing the pipe direction.
Factors which will influence the choice between elbows and bending are:
i.
local experience with bending
ii.
availability of pipe bending machines
The project specification for piping systems shall state which pipes shall be bent.
Pipe bending shall be performed in accordance with PTS 12.30.05.
However pipe bending at site should be restricted to DN50 and below only.
8.4.4
Mitre bends
Mitre bends may be only used in ASME rating class 150 and with the approval of the Owner.
Mitre bends shall be calculated according to ASME B31.3.
For upstream application, mitre bends shall not be used in piping system for any services.
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BRANCH FITTINGS
8.5.1
A branch fitting connects a branch pipe to the run pipe.
8.5.2
Branches should be connected at 90° to the run pipe. Branch fitting selection shall be as per
branch selection table provided in each piping class (PTS 12.31.01 and PTS 12.31.02).
8.5.3
Butt-welding tees should be used for branches equal in diameter to the run pipe.
8.5.4
Butt-welding tees with equal or reducing outlets should be used for services where flow
disturbance is to be minimised.
8.5.5
Economic aspects and service conditions shall be considered in the selection of the
reinforcing method.
8.5.6
Standard butt-weld end tee fittings shall be used in severe cyclic service.
8.5.7
Branch connections shall not be made on elbows or concentric reducers. Branch connections
should not be made on eccentric reducers or tees but may be made if the branch is maximum
DN 40 and the run-size of the fitting at the branch position is minimum DN 150. On eccentric
reducers the branch shall be located at the flat side of the reducer. On tees the branch shall
be located opposite the main branch of the tee.
8.5.8
For 90 degree branch connections size DN 40 and below in non-coated or lined carbon steel
piping classes, flanged branch fitting outlets (BNIF) shall be utilised in lieu of plain end branch
outlet fittings (BNIP).
FLANGES
8.6.1
Flanges shall be raised-face in accordance with ASME B16.5. Flanges over DN 600 (NPS 24)
shall be in accordance with ASME B16.47 series A and from ISO 10423/API 6A for wellhead
and X-mas tree connections. PTS piping classes are standardized based on ASME B 16.5 and
B16.47 Series A flanges.
8.6.2
ASME B16.47 Series B flanges may be accepted for utility and non-sour hydrocarbon piping
systems up to class rating 600# and not subjected to cyclic service, Hydrogen service, toxic
service and/or excessive external load from rotating equipment. In such cases piping class
shall be developed or derived accordingly.
8.6.3
The flange facing finish shall be in accordance with ASME B16.5 or ASME B16.47, as
applicable.
8.6.4
Flange bolt holes shall straddle the centre lines.
8.6.5
If a flat face flange is required (e.g. GRE piping in ASME rating class 150) the counterflange
shall also have a flat face in accordance with ASME B16.5. Flat face flanges shall be provided
with full-face gaskets.
8.6.6
For bolt material and temperature limitations reference is made to (8.3.3) and PTS 15.01.01.
8.6.7
For bolt tensioning, see 3.11 and for bolt tensioning equipment, see PTS 12.00.03.
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ISOLATION
8.7.1
General
Isolation of equipment and pipes may be required for the following:
i.
For individual pieces of equipment in an otherwise live plant.
ii.
For a production unit as a whole.
iii.
For safe entry of personnel.
iv.
v.
To carry out maintenance.
To avoid flammable or toxic release to atmosphere.
vi.
To avoid contamination of products.
vii.
To avoid unwanted transmission of products
-
(flammable/toxic/asphyxiates/utilities)
viii.
To divert a product elsewhere.
ix.
To quickly stop a product flow in case of emergency.
x.
To quickly release/divert a product flow to flare/blow down/safe location.
From the process/safety requirement for isolation, the desired tightness and the desired
speed of isolation can be derived.
8.7.2
Standard Isolation
Valve isolation is the standard way of separating systems. This type of isolation is provided
in all cases where no specific tightness requirements are justified and where planned use of
the isolation can be foreseen during the design stage.
Where a bleed valve is provided, the purpose of the bleed is to verify if the valve has seated
and tightness has been reached before spading and to provide a means of draining or
depressurising the volume between spade/blind and isolation valve.
The preferred take off point of the bleed is at the top of the line, especially in fouling
systems.
8.7.3
Single valve isolation
i.
Single valve isolation shall be limited to:
a) Fluids not classed as very-toxic and fluids that are non-flashing, in
pressure classes 600# and below;
b) Fluids containing hydrogen, in pressure classes 300# and below;
c) Flashing fluids (as defined in IP 15), in pressure classes 300# and below.
ii.
Single valve isolation shall be complemented with bleed valve(s) for the
following:
a) Unless the normal operating temperature is ambient, a blanked bleed
valve shall be provided at the downstream side of isolation valve and
spade/blind.
b) A blanked bleed valve shall also be provided between an isolation valve
and spade/blind for line sizes ≥ DN 150.
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Single block valves with bleed connection, see Figure 2.
Figure 2: Single block valves with bleed connection
8.7.4
Double valve isolation
i.
As a minimum double valve isolation shall be provided for the following:
a) Piping systems containing very-toxic fluids (e.g. H2S > 500 ppm), in all
pressure classes;
b) Piping systems containing flashing fluids or fluids containing hydrogen,
or steam in pressure classes 600# and above;
c) All piping systems other than hydrogen and steam, in pressure classes
900# and above for downstream facilities;
d) System containing LPG or liquids with which, when released at
atmospheric pressure, will result in a significant fraction of liquid portion
being flashed as flammable vapor.
e) All offshore facilities system :
 Class 600# or above for hydrocarbon process system (due to the
flammable nature of the fluid streams). This includes isolation for all
instrument (e.g. control valves, relief valves, level gauges, PI/PT)
mounted on pressurized fluid containing equipment or piping.
 Class 900# or above for non-hydrocarbon utility systems e.g.
seawater, wash water, instrument/utility air, etc. (due to the high
pressure of the systems).
 System which has design temperature of higher than 120°C and
where the flash point of the medium is less than 38°C (e.g.: Methanol
flash point = 11oC, Hydrocarbon Condensate flash point =21oC).
 All pig launchers/ receivers irrespective of the service
ii.
Drain points rated for the upstream connection pressure which fall under one of
the above criteria mentioned in (v) and (vi) for double block and bleed isolation
assembly. A common, second block valve, can be located on the common drain
header. Refer to schematic below.
Note: Application of double block and bleed valving isolation assembly for multiple process trains need to be
reviewed on a case by case basis depending on the operating philosophy of the plant.
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iii.
Single valve isolation may be used instead of double valve isolation for the
following:
a) At a pressure rating break point a single valve may be sufficient if two
valves in series are available at a second isolation point at the high
pressure side (e.g. a pump can have a single suction valve when the
discharge is equipped with two tandem valves).
b) Single valve isolation inside a (package) unit/plant for pumps, relief
valves, etc. in combination with a vent valve is acceptable if it is allowed
to shut down the unit/plant in case a valve should pass.
iv.
Double valve isolation shall be complemented with bleed valve(s) for the
following:
a) Double bleed valves shall (PSR) be provided for flashing fluids, or very toxic
fluids. This includes isolation for all instrument (e.g. control valves, relief
valves, level gauges) mounted on pressurized fluid containing equipment
or piping. The downstream side of the bleed valves shall (PSR) be:
 connected to safe location for fluids classed as very toxic – acute and
for flashing fluids,
(NOTE: if not connected to flare, but lined up to atmosphere in LPG service, the minimum distance
between the two bleed valves shall not be less than 0.7 m .Operation of LPG bleed valves will lead
to low temperatures due to the expansion of the fluid. Any free water associated may lead to ice
formation that prevents the block from being closed. 0.7 m has been tested to give sufficient
distance to still close the upstream valve when water/icing might have blocked the downstream
drain valve.)

connected to a closed disposal/incineration/flare system for fluids
classed as very toxic – carcinogenic or very toxic – mutagenic;
For double block valves with bleed connection to safe location, Ref Fig. 3.
Figure 3: Double block valves with bleed connection to safe location
v.
Single bleed valve shall be provided for all other fluid services, with bleed valve
blanked off in the following cases:
a) between an isolation valve and spade/blind for line sizes DN 150 and
above;
b) at control valves with a by-pass;
c) where double block valves with a bleed are used to safely turn a
spectacle blind or insert a spade while both process ends remain under
-process conditions;
d) where large valves in fouling service are frequently switched
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For double block valves with bleed connection, see Figure 4.
Figure 4: Double block with bleed connection
Where double valve isolation is required, it shall (PSR) be applied to:
i.
control valves with by-pass sets
ii.
the upstream side of relief valves requiring isolation valves
iii.
pumps
iv.
level gauges
v.
other on-stream equipment isolation
A double block and bleed arrangement is sometimes applied at low pressures for operational
reasons, for example to prevent product contamination or to isolate utility connections which
are regularly and quickly needed.
8.7.5
Isolation of control valves
Isolation of control valves from high pressure is further discussed, since normally they will
not be equipped with a depressuring connection hard piped to a safe location, but only with
a capped/blanked bleed valve.
The following cases can be considered:
i.
The configuration with double block valves upstream and downstream of the
control valve with a capped/blanked bleed directly upstream of the control valve
is normally applied, refer to Figure 5.
Figure 5
ii.
If the downstream block valve is located at a piping class break point the second
block valve can be omitted, refer to Figure 6.
Ans 900
Ans 300
Figure 6
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iii.
In very high pressure systems when flanges have to be avoided to the maximum
extent two control valves in parallel shall be installed each equipped with a block
valve upstream and no further isolation facilities (refer to Figure 7). This implies
acceptance of a system shut down when both control valves fail.
Figure 7
8.7.6
Integral double-block-and-bleed valves
Double-seated valves with one-piece closure members (e.g. gate, ball and plug valves) and a
body bleed shall not be considered as proper double-block-and-bleed valves since a common
mode failure may make both isolations ineffective. However, they can be used to give a more
reliable isolation than single-seated valves, or can be used to prevent product contamination
(e.g. in oil movement operations).
For single-body, single-stem double-block-and-bleed applications, only two valve concepts
are acceptable:
i.
double expanding gate valve with body bleed valve
ii.
double expanding plug valve with body bleed valve
Avoidance of common mode failure is achieved by independent alignment of closure member
parts to mating seats. The single stem of the double expanding gate valve or double
expanding plug valve is in compression when closed. This eliminates the dominant stem
failure modes. Additional advantage of the double expanding gate valve and double
expanding plug valve is that external seating forces can be applied to assist seat tightness,
especially for the low differential pressure seat of the DBB configuration. The double
expanding gate valve and double expanding plug valve shall achieve gas tight sealing. The
bleed valve shall comply with piping class valve requirements.
Internal obstruction of one of the closure member parts renders the entire valve
dysfunctional. This aspect should be carefully considered when choosing this concept over a
double-block-and-bleed assembly made out of individual valves.
Other acceptable integral double-block-and-bleed valves are:
i.
integral double ball valve with body bleed valve
ii.
integral double plug valve with body bleed valve
The bleed valve shall comply with piping class valve requirements.
Only the valve body is shared in these designs. Therefore these valve concepts can be
considered as similar to double-block-and-bleed assemblies made out of individual valves.
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POSITIVE ISOLATION (“SPADING”)
8.8.1
General
Positive isolation is a procedure whereby physical separation between systems is achieved.
NOTE.
Closing valves does not achieve positive isolation.
The need for positive isolation is dictated by special safety and/or process requirements.
Positive isolation shall (PSR) be provided when:
i.
hot work is to be done; or
ii.
equipment is to be hydrostatically tested; or
iii.
entry by personnel is required for inspection or maintenance; or
iv.
equipment is to be opened or removed whilst the remainder of the unit is still in
operation
If personnel are to enter the equipment, the points of positive isolation should be as close as
possible to the equipment.
Positive isolation can be achieved by:
i.
spectacle blinds incl. quick-acting blinds
ii.
spades
iii.
removable spools with blind flanges
iv.
blind plates
Spectacle blinds, spades, spacers and blind flanges shall have the same ASME rating class as
the piping. For spectacle blinds, spades and spacer see Standard Drawings D12.92.305,
D12.92.311 and D12.92.312.
If spades with spacers are required which are outside the range of Standard Drawings
D12.92.311 and D12.92.312, their outside diameter shall be equal to the diameter of the
raised face of the mating flange. Spacers and spades shall have two centring pieces welded
to their circumference. These centring pieces shall have a bolt hole of the same diameter and
bolt circle diameter as the mating flange.
If spectacle blinds in horizontal pipes are insulated, the spectacle blind should point
downwards at an angle of 45° to avoid water leaking into the insulation (see PTS 15.13.01).
In order to prevent icing problems, spectacle blinds shall not be installed in pipes with
operating temperatures below 0 °C. In order to avoid excessive condensation in high humidity
locations, spectacle blinds should not be installed at places where the temperature is below
the dew point. In both situations, spades should be used instead of spectacle blinds.
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Quick-acting blinds or line blind valves (e.g. “Hamer”) may be used for frequent pipe blinding
if approved by the Owner. The seat material shall be suitable for the fluid and operating
temperature.
If it can be guaranteed that there will be no differential pressure between both sides of the
isolation point (even not via a utility or instrument connection), a thin (3 mm to 5 mm) blind
plate may be installed instead of a spectacle blind or a spade. The blind plate shall be provided
with gaskets on both sides in order to prevent damage to the surfaces of the mating flanges.
Piping shall be designed, supported and installed so that the flanges do not move when the
bolting is removed for spading purposes. The piping shall be sufficient flexible to be able to
install the required isolation fittings (spades, blind plates etc.) and there shall be sufficient
space to turn spectacle blinds, where provided.
8.8.2
Ergonomic aspects
Spectacle blinds and spades shall be located so that they are accessible from ground level or
from platforms or walkways. The need for scaffolding shall be minimised.
For easier handling, spading points should not be installed in vertical piping; if this is
unavoidable, special precautions shall be taken to improve access and handling.
Turning a spectacle blind requires all bolts except two to be removed and a small opening to
be made between the flanges. A relatively large force is required to turn a large spectacle
blind. A spectacle blind cannot easily be turned using a crane or a hoisting device, and
therefore the need for cranes and hoisting facilities shall be avoided. Personnel should not
pull or lift loads exceeding 250 N. If the required force to turn spectacle blinds exceeds 250
N, spades with spacers should be used instead.
Spectacle blinds requiring a force of more than 250 N are tabulated below.
ASME rating class
Size DN
150
450 and larger
300
400 and larger
600
350 and larger
900
300 and larger
1500
300 and larger
2500
300 and larger
To remove a spacer (or its replacement spade) half of the bolts need to be removed and the
flanges opened slightly.
Spades and their corresponding spacers shall be clearly tagged and properly stored in
adequate facilities when not in use.
To install a spade between two flanges that did not have a spacer requires the flanges to be
opened by a distance equal to the thickness of the spade plus one gasket. Spades without a
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spacer may only be applied in relatively flexible piping systems and shall not be used for
spading rotating equipment in order to avoid distortion problems.
Spacers and spades exceeding a weight of 250 N should be provided with a lifting lug. A
mobile crane or, if this is not possible, special hoisting facilities should be used for handling
such items.
Spades having a weight of more than 250 N are tabulated below:
ASME rating class
Size DN
150
350 and larger
300
300 and larger
600
250 and larger
900
200 and larger
1500
200 and larger
2500
150 and larger
A removable spool and blind flanges shall be used in the following situations:
i.
where the nozzle is used for entry into the equipment
ii.
where the nozzle is used for hoisting purposes (e.g. top nozzles on columns)
iii.
where the nozzle (e.g. the head of a heat exchanger) is used to remove internals
(e.g. the tube bundle)
iv.
where the nozzle is used for loading/unloading of solids (e.g. catalyst)
VALVES
8.9.1
General
For economy and interchangeability, a minimum number of valve types shall be selected.
The following duties of valves are defined:
i.
stopping of fluid flow when closed, with minimum flow resistance and pressure
drop when open
ii.
flow regulation
iii.
back-flow prevention
iv.
pressure regulation, maintaining constant downstream pressure by variable
valve opening
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8.9.2
v.
pressure relief, to safeguard the system against excessive pressures that may
cause damage to, or failure of, the protected system
vi.
special valves for abnormal conditions e.g. ESDs
Selection of valves
i.
General
a) If piping classes allow various valves to be used, their selection shall be
based on operational requirements and economic considerations.
b) For special valves outside the scope of the piping classes, the following
factors shall be considered in valve selection:
-
pressure
temperature
erosiveness, corrosiveness and toxicity of service
fouling or non-fouling service
throttling or open/close service
isolating service, required level of leak-tightness
required capacity
type of valve operating mechanism (handwheel, wrench, gearbox
etc.)
safety requirements such as:
 fail-safe position
 minimum and maximum time for opening and closing
 requirements in the event of fire
c) Any type of bi-directional valve is suitable for isolation, provided it is
properly designed and installed.
d) Double-seated valves (e.g. gate, ball and plug valves) with a body bleed
shall not be considered to be proper double-block-and-bleed valves since
a common failure may still make both isolations ineffective. However,
they can be used to give a more reliable isolation than single-seated
valves, or can be used to prevent product contamination (e.g. in oil
movement operations).
e) Ball valve body may be of split body or all welded construction and shall
be flanged end configuration. Split body configuration shall be utilised in
size DN 600 and below to facilitate shop maintenance. Top entry valves
maybe offered as an alternative but are unlikely to be commercially
attractive. In-situ maintenance of top entry valves is not currently an
option within PETRONAS and this need not be used as a selection criteria.
f) For additional general, material, and testing/inspection requirements for
ball valves refer to respective project specification.
ii.
Stop flow, main or block valves
Piping classes specify which valves are to be selected for a particular service or duty,
generally in accordance with guidelines specified in PTS 12.32.02
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iii.
Valves in steam service
All valves for steam service in ASME rating class 600 and higher shall be of the
butt weld end type, except for equipment assembly valves, blow-down valves
and instrument isolation valves, which may be flanged.
iv.
Valves in hydrogen service
Valves for pure hydrogen or fluids containing hydrogen in piping classes 600
and higher should be butt welded except for check valves and instrument
isolation valves, which may be flanged.
Valves in hydrogen service require special attention with regard to external
leakage, which can be prevented by different methods depending on the
required level of tightness and economics (see below vii. External leakage
prevention).
v.
Valves in low temperature service
a) Acceptable valve types for low temperature services are specified in BS
6364 and PMRC MAR VA/200 and MAR VA/136.
b) Gate, globe, ball and butterfly valves in low temperature service shall
have a vapour space sufficient to maintain the stem packing at a
temperature high enough to permit actuation of the valve.
c) The vapour space of valves in services between 0 °C and minus 50 °C is
defined in PMRC MAR VA/136.
d) The vapour space of valves in services below minus 50 °C is defined in
PMRC MAR VA/115. Depending on the valve design, this may require
extended valve bonnets.
e) For low temperature service, valves with extended bonnet shall be used.
However, for systems which operate occasionally below minus 20 °C (e.g.
during de-pressuring) and have a lower design temperature between
minus 20 °C and minus 50 °C, do not require valves with extended
bonnets. Such valves shall not be opened or closed at sub-zero
temperatures.
f) The vapour space is specified so that in flashing services (e.g. LPG or LNG)
a gas cap will form under the stuffing box which acts as a thermal barrier
and protects the valve against malfunctioning due to freezing. In order
to maintain this gas cap, the valve stem shall be positioned with an
inclination no more than 30° from vertical.
g) Valves in no-flow connections (such as vents and pressure gauges) and
valves in methanol service, where the trapped gas bubble protects the
valve packing from too low temperatures, may be installed at an angle
up to 90° from vertical (i.e. they may be installed in vertical pipes).
h) Drain valves shall be installed with the stem inclined no more than 30°
from vertical. The drain connections shall be provided with
support/bracing, preferably to the header (see Standard Drawing
D12.92.357).
vi.
Valves in very toxic service
Valves in very toxic service require special attention with regard to external
leakage, which can be prevented by different methods depending on the
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required level of tightness, economics and legal requirements (see below vii.
External leakage prevention)
vii.
External leakage prevention
External leakage of valves can be minimized by the use of:
a) quarter-turn valves instead of rising stem valves
b) rising stem gate valves and globe valves with a welded bonnet and
bellows seals
c) valves with double seats, with or without a sealing/protection medium
d) valves with special stuffing box designs (e.g. live-loading) and special
packing materials (cup and cone or wedge rings), as listed in PMRC MAR
GS/109
viii.
Valves in ethylene oxide (EO) service
a) General
- Non-metallic components shall be selected in accordance with the
list published by BAM (Bundesanstalt für Material-Forschung).
- The gland packing shall be high purity (98%) flexible compressed
graphite.
- There shall be no sealant injection connections for stem sealing.
- The valve geometry shall be designed so that there are no zones that
could generate energy or initiate a fire, e.g. high velocities,
turbulence and/or uncontrolled temperature elevation by adiabatic
compression. All internal conduit surfaces shall be machined
smooth.
- In the fully open position, the port opening shall be not less than 70%
of the nominal bore.
- Valves for EO service shall be internally clean and free from moisture,
oil and grease.
- Valves for EO service shall have a conspicuous label, stating the
words “ETHYLENE OXIDE SERVICE”
b) Butterfly valves
Triple-eccentric butterfly valves are preferred in EO service due to their
short closure time.
c) Gate, globe and check valves
- Gate and globe valves in EO service shall have a bellows-sealed or
special gland packing construction.
- Gate, globe and check valves shall have metal body seats. Metal seat
rings shall be integral, weld-in or screwed-in. Screwed-in seats shall
be secured against loosening.
- Over-pressurization and pressure locking may be caused by EO
polymerization and by the entrapment and subsequent heating of
liquid in the valve cavity of double-seated valves. To prevent such
over-pressurization, the gate valves shall have a pressure relief
feature as specified in (3.12.6).
- Valves in nominal sizes DN 40 and smaller shall have a welded bonnet
or cover connection with full penetration welds.
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-
For valves with special gland packing constructions in nominal sizes
DN 50 and larger, a bolted bonnet connection is allowed in all
pressure classes.
d) Ball valves
Ball valves used in EO systems shall have a pressure-equalising hole
drilled in the ball and shall be fitted with metallic seats.
ix.
Flow regulation (throttling valves)
a) For flow regulation valves selection refer PTS 12.32.02.
b) Control valves selected for throttling purposes shall not be used for an
isolation function. For selection of control valves, see PTS 14.10.04.
x.
Back-flow prevention (check valves)
a) The table below summarises the typical selection of check valves:
Check valves
DN 15 to DN 40
DN 50 and larger
DN 50 and larger
Piston-type, horizontal flow
Swing-type
Dual-plate type, spring-energized
b) Check valves are designed to prevent the reverse flow of liquid or
gaseous products. Check valves shall not be relied upon for positive
isolation purposes.
c) Small check valves (DN 15 to DN 40) are normally of the piston-type and
shall be used only in horizontal pipes.
d) Swing-type check valves may be used in horizontal pipes and in vertical
pipes when the flow is upwards.
e) Non-slam, tilting disc and “feather”-type check valves shall be used
where unacceptable pressure surges would otherwise be caused.
f) Non-slam axial flow piston-type check valves are very reliable in clean
service and have a low pressure drop. These check valves shall not be
used in fouling services due to the close tolerances of the moving parts.
g) Utility pipes connected to pressurized process equipment or piping shall
be equipped with a check valve to prevent process fluids from entering
the utility system. The piping class “break” between utility piping and
process piping shall be located so that at least two valves (including the
check valve) satisfy the process piping class. More secure safeguarding
systems shall be applied if hazardous situations can arise upon failure of
such a system.
h) Check valves which could convey a relief flow (in the forward direction)
under fire conditions shall be of a fire-safe type. For fire safe
requirements see (8.8.5.ii).
i) Dual-plate check valves have a short face-to-face flange design and are
therefore lighter and more compact than swing type check valves. Only
dual plate check valves of retainer less design shall be used.
8.9.3
Pressure relief valves and depressuring valves
Refer to PTS 16.52.04 and PTS 12.32.01.
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8.9.4
Special valve types and their application
i.
Special valves have been developed and proven suitable for process
requirements and special services. Care shall be taken to select the correct
valves, with a view to the design, materials, fabrication and testing.
ii.
Examples of special valves are:
a) Ram-type drain valve, A flush bottom valve (i.e. without a dead nozzle
end) with a piston extending upwards, used for viscous or solidifying
products, e.g. in reactors and mixing vessels.
b) Flush bottom valve, Drain valve without a dead nozzle end, used on
piping or equipment containing viscous products.
c) Plug valves, periodic maintenance by trained staff and therefore their
use shall be minimised.
- Lubricated plug valves should not be used for general purposes and
shall only be used if the product allows the use of a plug lubricant.
- Lined or sleeve-type plug valves may be used in pipes containing very
toxic substances but not containing scaling deposits or suspended
solids.
- In high pressure gas systems the use of pressure-balanced (nonlubricated) plug valves may be considered.
- Inverted pressure balanced, lubricated plug valves may be used as
bypass / equalising and blow down valves in hydrogen and natural
gas pipes and as kicker and drain valves of scraper traps.
d) Multi-port valves
Two conventional valves should be used for diverting flow but if this is
impractical (e.g. due to space restrictions), multi-port ball valves or multiport plug valves may be used after approval by the Owner.
e) Iris-type valve with diaphragm closure member
This type of valve may be used for pneumatic or gravity feed of solids
and powders.
f) Excess flow valves
Excess flow valves are designed to shut when the flow rate exceeds
design flow rates, e.g. in the event of a hose burst. They should not be
used in refinery or depot emergency shutdown systems for storage
vessels, loading points or multi-product systems, since they are not
sufficiently reliable in providing positive shut-off.
g) Rotary star valves
Rotary star valves are designed for solids handling, e.g. dosing of catalyst.
These valves are not tight shut-off.
h) Solids sluicing valves
Special through-conduit gate valves may be used for solids sluicing duties
(gravity flow).
i) Isolators and dampers
Various valve types (e.g. flap, guillotine, louver) are available for flue
ducts and gas turbine exhausts. These valves are for low pressures and
their tightness ranges from 95% to 100%. They are suitable for both shutoff service and regulating service.
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8.9.5
Special properties of valves
i.
Tight Shut-Off (TSO) requirements:
a) Tight shut-off valves shall be marked “TSO” on the P&ID.
b) Valves are considered TSO if they comply with seat leakage rates A or B
according to ISO 5208 and BS 6755-1, or to class V or VI in accordance
with IEC 60534-4.
c) TSO valves are more expensive than valves satisfying standard leakage
requirements and shall only be used if standard seat leakage cannot be
tolerated.
d) Control valves shall not be considered TSO because:
- Certain types of control valves (e.g. low noise valves) cannot, as
standard, be manufactured to meet TSO requirements.
- Control valves will lose their TSO characteristics quickly after being
used in operation.
e) A practical solution in such cases is to install a normal control valve in
combination with a TSO valve.
ii.
Valves with fire safe design or fire tested design requirements
a) Fire safe properties of valves are determined by the materials and
construction of the valves.
b) Valves with a fire tested design are those which have successfully passed
prototype fire testing.
c) Fire safe valves are those which are individually capable of passing fire
tests.
d) Valves shell be fire tested and certified in accordance with ISO 10497, BS
6755 part 2 API 607 or API 6FA and are subject to approval by the Owner.
e) Valves are considered fire safe if, after being engulfed in flames of a
certain intensity for a certain period of time:
-
the seat leakage of the valve does not exceed a set requirement
the external leak rate (e.g. via the valve spindle or valve body joints)
remains within specified limits
d) Valves with a fire safe design shall be certified to API 607, ISO 10497, BS
6755-2 and API 6FA and API 6FB.
NOTE: Standards API 607, API 6FA, BS 6755-2 and ISO 10497 do not address the capabilities of the
valve end connections. End connections shall be fire tested in accordance with API 6FB.
e) If a fire safe metal seated butterfly valve or dual plate check valve is
required, valves with (dual) flanged ends or, for the larger sizes, butt
welded ends shall be used. Alternatively, wafer lug type or single flanged
valves may be considered since their long bolts are not exposed.
f) Valves with a fire tested design:
- Soft seated quarter turn valves shall have a secondary or primary
metal sealing
- The sealing arrangement of these valves shall be capable:
 to withstand a minimum of 6000 cycles of operation
 of passing fire test to API 607 and API 6FB
g) Non fire safe valves
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-
-
-
8.9.6
Wafer type valves are not fire safe. The long unprotected bolts will
expand in a fire sooner than the flanges and lose their properties,
thereby causing leakage and escalation of the fire. Therefore wafer
type valves shall not be used in hydrocarbon service.
Lined valves, such as ball, check, diaphragm and butterfly, are not
fire safe and shall only be used in systems which contain nonflammable products.
Sleeve-type plug valves may be fire-safe to the outside, but the seat
will pass fluid after exposure to high temperatures. Therefore they
cannot be classified as fire safe and may only be used in hydrocarbon
services (flammable products) if they have successfully passed fire
testing
Repair and reconditioning of valves
If economically attractive to do so, valves may be repaired or reconditioned, provided that:
i.
they are returned as close as possible to the original manufactured condition
ii.
the guidelines of API RP 621 are taken into account
iii.
they are equipped with the same components and materials (e.g. gaskets and
packing) as the original valves
iv.
they meet the same specifications as the original valves
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INSPECTION AND TESTING
SHOP-FABRICATED OR MANUFACTURER-SUPPLIED PIPING
9.1.1
Metallic piping
Shop-fabricated metallic piping shall be inspected and tested in accordance with ASME B31.3
and PTS 12.30.05. Metallic piping materials not covered by PTS 12.30.05 shall be inspected
and tested as specified by the Owner.
If expansion joints are installed in the horizontal position in pipes operating below 0 °C, and
if the expansion joints cannot be removed for the hydrostatic test, the pipes may have to be
tested pneumatically instead of hydrostatically in order to avoid ice forming in the
convolutions of the bellows. See PTS 12.02.01. For testing of expansion joints, see also ASME
B31.3.
9.1.2
Lined piping
Lined piping shall be inspected and tested in accordance with the Manufacturer’s test and
inspection procedures, which shall be subject to the approval of the Owner. PTS 15.20.03,
PTS 15.20.04 and PTS 15.20.07 shall also apply.
9.1.3
Non-metallic piping
Thermoplastic and glass-fibre reinforced polyester (GRP) piping shall be inspected and tested
as specified in the relevant PTS, see (8.2.2). Other non-metallic piping shall be inspected and
tested in accordance with the Manufacturer’s test and inspection procedures, which shall be
subject to the approval of the Owner.
FIELD-FABRICATED PIPING
9.2.1
Metallic piping
Field-fabricated metallic piping shall be inspected and tested in accordance with ASME B31.3
and PTS 12.30.05. For field inspection prior to commissioning, see PTS 12.02.01.
VALVE INSPECTION
Refer to PTS 12.32.02.
PRESSURE TESTS
9.4.1
All piping system shall be pressure tested in accordance with ASME B31.3.
9.4.2
For pressure tests of piping system related to upstream facilities, see Section 9.4 of Appendix
15 of this PTS.
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INSULATION
THERMAL INSULATION
10.1.1 For thermal insulation of piping (including that for personnel protection), see PTS 15.13.01.
10.1.2 On top of insulated columns and tanks, and over piping, where applicable, grating should be
provided to avoid damage to insulation.
10.1.3 In the following situations flanges shall (PSR) not be insulated.
i.
flanges in hydrogen service
ii.
flanges in systems containing hydrocarbons above their auto-ignition
temperature
iii.
if the 80% rule for bolting has been applied in accordance with ASME B31.3
10.1.4 Insulated flanges
i.
If flanges with a design temperature above 400 °C are insulated, the bolt stress
(after relaxation) shall remain within the required seating stress of the applied
gasket type.
ACOUSTIC INSULATION
10.2.1 PTS 15.13.02 shall apply for acoustic insulation.
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December 2017
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PAINTING AND COATING
11.1.1 PTS 15.20.03 shall apply for painting and coating of new piping and maintenance painting.
11.1.2 Galvanised and non-metallic piping should not be painted other than for colour coding
requirements unless it is requested by Owner.
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BIBLIOGRAPHY
In this PTS, reference is made to the following Standards/Publications. Unless specifically
designated by date, the latest edition of each publication shall be used, together with any
supplements/revisions thereto:
PETRONAS STANDARDS
Index to PTS
PTS 00.01.01
Requirements, General Definitions of Terms, Abbreviations &
Reading Guide
PTS 00.01.03
Drainage and primary treatment systems
PTS 11.12.03
Layout of Offshore Facilities
PTS 11.22.06
Design of cathodic protection systems for onshore buried
pipelines
PTS 11.32.01
Symbols and identification system – mechanical
PTS 12.00.02
Mechanical Maintenance Equipment, Tools and Bolt Tensioning
PTS 12.00.03
Bolted Flange Joint Assembly (Amendments/ Supplements to
ASME PCC-1)
PTS 12.00.06
Field inspection prior to commissioning of mechanical
equipment
PTS 12.02.01
Plant model construction and review
PTS 12.03.01
Layout of Onshore Facilities
PTS 12.03.04
Pumps – type selection and basic design requirements
PTS 12.11.01
Reciprocating positive displacement pumps and metering
pumps
PTS 12.11.04
Reciprocating compressors
PTS 12.11.32
Package, integrally geared, centrifugal plant and instrument air
compressors
PTS 12.11.34
Pressure vessels
PTS 12.20.01
Pressurized bulk storage installations for LPG
PTS 12.20.02
Heat exchangers – Shell and Tube type
PTS 12.21.01
Standard vertical tanks – selection, design and fabrication
PTS 12.22.01
Piping classes – basis of design
PTS 12.30.01
Pipe supports
PTS 12.30.04
Shop and field fabrication of steel piping
PTS 12.30.05
Protective steam heating of piping systems
PTS 12.30.06
Piping classes – Refineries, Chemical And Gas Plants, Onshore
Exploration And Production Facilities
PTS 12.31.01
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Piping classes – Exploration And Production (Offshore)
PTS 12.31.02
Relief valves – selection, sizing, specification, inspection and
testing
PTS 12.32.01
Piping valve – Selection, inspection and testing
PTS 12.32.02
Steam traps – Design, selection and installation
PTS 12.32.04
Specification for piping systems
PTS 12.34.01
Glass-fibre Reinforced Plastic pipelines and piping systems
PTS 12.34.02
Thermoplastic piping
PTS 12.34.04
Pipe stress analysis – Basis for design
PTS 12.35.01
Water-tube boiler installations
PTS 12.40.01
Fired heaters based on ISO 13705
PTS 12.41.01
Electrical trace heating
PTS 13.13.02
Instruments for measurement and control
PTS 14.10.02
Control valves: selection, sizing and specification
PTS 14.10.04
Installation of on-line instruments
PTS 14.10.06
On-line process stream analysis – sample take-off and
transportation
PTS 14.30.01
Metallic materials – selected standards
PTS 15.01.01
Non-metallic materials – selection and application
PTS 15.01.02
General Selection of Materials For Life Cycle Performance (EP)
PTS 15.01.03
Materials for Use in H2S-Containing Environments in Oil and
Gas Production (Amendments and Supplements to
ANSI/NACE/MR0175/ISO 15156)
PTS 15.01.05
Cleaning of equipment
PTS 15.05.01
Metallic materials – prevention of brittle fracture
PTS 15.10.01
Welding of metals
PTS 15.12.01
Oxidation of stainless steel weldments
PTS 15.12.03
Thermal insulation (amendments/supplements to the CINI
Manual “Insulation for Industries”)
PTS 15.13.01
Acoustic insulation for pipes, valves and fittings
PTS 15.13.02
Cathodic protection
PTS 15.20.01
Protective Coatings and lining
PTS 15.20.03
Cement lining of pipes
PTS 15.20.04
Rubberined process equipment and piping
PTS 15.20.07
Glass-lined steel equipment and piping
PTS 15.20.10
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Maintenance painting
PTS 15.20.12
Hydrogen induced cracking sensitivity test
(Amendments/supplements to NACETM0284)
PTS 15.23.01
Fouling resistances for heat transfer equipment.
PTS 16.12.01
Definition of temperature, pressure and toxicity levels
PTS 16.50.01
Fuel systems
PTS 16.39.02
Instrument air supply
PTS 16.39.07
Chemical injection facilities
PTS 16.52.03
Pressure relief, emergency depressuring, flare and vent
systems
PTS 16.52.04
Gaseous oxygen systems
PTS 16.52.05
Internals for columns
PTS 16.52.06
Gas/liquid separators – type selection and design rules
PTS 16.52.09
Water based fire protection system for offshore facilities
PTS 16.54.01
Assessment of the fire safety of onshore installations
PTS 16.73.01
Active fire protection systems and equipment for onshore
installations.
PTS 16.73.02
Human factor engineering – Valve criticality analysis
PTS 16.74.02
PMRC MAR datasheets and additional specifications for piping
components
PMRC Groups PT, FF,
VA, BL and GS
STANDARD DRAWINGS
Wall type gauge glass with reflex or transparent glass
D12.92.009
Bund wall – typical details
D11.92.004
Standard Drawings for fired heaters
D12.92.067 to
D12.92.206
Y-type strainers, ASME classes 150 and 300
D12.92.301
Bucket-type suction strainer carbon steel ASME class 150
D12.92.302
Steam sample device
D12.92.304
Spectacle blinds for ASME flanges
D12.92.305
Product sample cooler (cooling water: fresh or brackish)
D12.92.306
Sample cabinets with inlet on top. Material: carbon steel or
low-alloy steel
D12.92.308
Sample cabinets with inlet on top. Material: stainless steel
D12.92.309
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Temporary strainer for compressors
D12.92.310
Spade blinds for ASME flanges
D12.92.311
Spacer for ASME flanges, for replacement of spades
D12.92.312
Level gauges – collar type ASME class 150 (PN 10)
D12.92.316
Displacer chamber
D12.92.317
Overall dimensions of plate-type level gauges through-vision
and reflex type
D12.92.318
Level gauges, collar type DIN 2501 (ND 10)
D12.92.320
Branch fittings
D12.92.331
High pressure welding thermowell for piping systems, DN 50
D12.92.338
Flanged thermowell, DN 40, ASME classes up to 1500 inclusive
D12.92.339
Flanged thermowell, DN 50, ASME classes up to 2500 inclusive
D12.92.340
Orifice flanges, raised face, with flange tappings. ASME classes
300 to 2500 incl., Nom. Size DN 50 to DN 600 incl.
D12.92.343
Orifice flanges, raised face, with corner tappings. ASME classes
300 and 600, Nom. Size DN 50 to DN 600 incl.
D12.92.344
Orifice meter runs with flanged ends, Nom. Size DN15 to DN40
incl., ASME classes 150 to 1500 incl.
D12.92.346
Steam ring to horizontal flanges of DN 150 and above in
hydrogen service
D12.92.347
Two steam rings to horizontal flange of DN 150 and above (with
spectacle blind, spade, spacer or orifice)
D12.92.348
Steam ring to vertical flange of DN 150 and above in hydrogen
service
D12.92.349
Two steam rings to vertical flange of DN 150 and above in
hydrogen service (with spectacle blind, spade or spacer)
D12.92.350
Sampling point assembly
D12.92.351
Typical bracings for small bore branches of piping (e.g.
drain/vent point)
D12.92.355
Typical bracings for small bore branches of piping (e.g. orifice
instrument connection)
D12.92.356
Typical bracings for small bore branches of piping (e.g. pressure
instrument connection)
D12.92.357
Steam lance
D12.92.374
AMERICAN STANDARDS
Specification for line pipe
API 5L
Pipeline valves
API 6D
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Specification for fire test for valves
API 6FA
Specification for fire test and end connections
API 6FB
Capabilities of API flanges under combinations of load
API TR 6AF
Specification for polyethylene line pipe (PE)
API 15LE
Guide for pressure and depressurizing systems
API RP 521
Reconditioning of metallic gate, globe and check valves.
API RP 621
Valve inspection and testing
API 598
Fire test for soft-seated quarter turn valves
API 607
Reciprocating compressors for petroleum, chemical and gas
industry services
API 618
Positive displacement pumps – reciprocating
API 674
Positive displacement pumps - controlled volume
API 675
Issued by:
American Petroleum Institute
Publication and distribution section,2101 L Street NW,
Washington, DC 20037, USA.
ASME Boiler and Pressure Vessel Code , Section I
ASME I
ASME Boiler and Pressure Vessel Code, Section II - Materials
ASME II
ASME Boiler and Pressure Vessel Code, Section IX - Welding
and Brazing Qualifications.
ASME IX
ASME Boiler and Pressure Vessel Code, Sec VIII Division 1/
Division 2
ASME VIII
Pipe threads
Pipe flanges and flanged fittings, steel nickel alloy and other
special alloy
Factory-made wrought steel buttwelding fittings
Metallic gaskets for pipe flanges - ring-joint, spiral-wound and
jacketed
Nonmetallic flat gaskets for pipe flanges
ASME B1.20.1
ASME B16.5
Cast copper alloy pipe flanges and flanged fittings
ASME B16.24
Butt welding ends
ASME B16.25
Large diameter steel flanges
ASME B16.47
Process piping
ASME B31.3
Liquid transportation systems for hydrocarbons, liquid
petroleum gas, anhydrous ammonia and alcohol
Refrigeration piping
ASME B31.4
Gas transmission and distribution piping system
ASME B31.8
Welded and seamless wrought steel pipe
ASME B36.10
ASME B16.9
ASME B16.20
ASME B16.21
ASME B31.5
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Stainless steel pipe
Performance test code on compressors and exhausters
ASME B36.19
ASME PTC-10
Issued by:
American Society of Mechanical Engineers
345 East 47th Street ,New York NY 10017 ,USA
Standard Specification for Forgings, Carbon Steel for Piping
Components
Standard specification for seamless carbon steel pipe for high
temperature service
ASTM A 105
ASTM A 106
Standard specification for alloy-steel and stainless steel bolting
materials for high-temperature service
ASTM A 193
Standard specification for carbon and alloy steel nuts for bolts
for high pressure and high temperature service
ASTM A 194
Standard specification for piping fittings of wrought carbon
steel and alloy steel for moderate and elevated temperatures
ASTM A 234
Standard Specification for Carbon Steel Forgings for Pressure
Vessel Components
ASTM A 266
Standard specification for alloy steel bolting materials for low
temperature service
ASTM A 320
Standard Specification for Carbon and Low-Alloy Steel Forgings,
Requiring Notch Toughness Testing for Piping Components
ASTM A 350
Standard specification for seamless and welded steel pipe for
low temperature service
ASTM A 333
Standard specification for piping fittings of wrought carbon
steel and alloy steel for low-temperature service
ASTM A 420
Standard specification for high temperature bolting materials,
with expansion coefficients comparable to austenitic stainless
steels
ASTM A 453
Standard Specification for Pressure Vessel Plates, Carbon Steel,
for Moderate and Lower Temperature Service
ASTM A 516
Standard specification for precipitation-hardening nickel alloy
bars, forgings, and forging stock for high temperature service
Standard specification for plastic-lined ferrous metal pipe,
fittings and flanges
ASTM B 637
ASTM F 1545
Issued by:
American Society for Testing and Materials
1916 Race St..Philadelphia, PA 19103,USA.
Standards of the Expansion Joint Manufacturers Association
EJMA
Issued by:
Expansion Joint Manufacturers Association
25 North Broadway,Tarrytown.,NY 10591,USA
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Materials resistant to sulfide stress cracking in corrosive petroleum
refining environments
NACE MR0103
Laboratory Testing of Metals for Resistance to Sulfide Stress Cracking
and Stress Corrosion Cracking in H2S Environments
NACE TM0177
Evaluation of Pipeline and Pressure Vessel Steels for Resistance to
Hydrogen-Induced Cracking
NACE TM0284
Methods and Controls to Prevent In-Service Environmental Cracking of
Carbon Steel Weldments in Corrosive Petroleum Refining Environments
NACE SP0472
Petroleum and natural gas industries — Materials for use in
H2S-containing environments in oil and gas production
NACE MR0175
Issued by:
NACE International,1440 South Creek Dr.Houston, TX 77084-4906, USA
BRITISH STANDARDS
Unplasticized polyvinyl chloride (PVC-U) pressure pipes for cold
potable water
Joints and fittings for use with unplasticized PVC pressure
pipes:
Part 1: Injection moulded unplasticized PVC fittings for solvent
welding for use with pressure pipes, including potable water
supply
BS 3505
BS 4346-1
Propylene copolymer pressure pipe
BS 4991
Specification for steel ball valves for the petroleum,
petrochemical and allied industries
BS 5351
Specifications for valves in cryogenic service
BS 6364
Polyethylene pipes (type 50) in metric diameters for general
purposes
BS 6437
Black polyethylene pipes up to nominal size 63 for above
ground use for cold potable water
BS 6730
Testing of valves:
Part 1: Specification for production pressure testing
requirements
Part 2: Specification for fire-testing requirements
Polyethylene pipes for the supply of gaseous fuels
BS 6755-1
BS 6755-2
BS 7281
Issued by:
British Standards Institution
389 Chiswick High Road, London W4 4AL,UK
Guidelines for the avoidance of vibration-induced fatigue in process
pipework (ISBN 1 870553 373)
MTD Publication
99/100
Issued by:
Marine Technology Directorate,6 - 8 Tudor Court
Brighton Road,Sutton,Surrey SM2 5AE,UK
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INTERNATIONAL STANDARDS
Industrial control valves
Part 4: Inspection and routine testing
IEC 60534-4
Issued by:
Central Office of the IEC
3, Rue de Varembé ,CH 1211 Geneva 20 ,Switzerland
Industrial valves - pressure testing of valves
ISO 5208
Testing of valves – fire type testing requirements
ISO 10497
Petroleum and natural gas industries — Materials for use in
H2S-containing environments in oil and gas production
ISO 15156
Issued by:
International Organisation for Standardisation
1, Rue de Varembé ,CH-1211 Geneva 20 ,Switzerland
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APPENDIX 1
: PIPE SIZING
1.1
PIPE SIZING
1.1.1
DN 15, DN 20, DN 25, DN 40, DN 50, DN 80, DN 100, DN 150, DN 200, DN 250, DN 300, DN
350, DN 400, DN 450, DN 500 and DN 600 in accordance with the following limitations:
Pipes with nominal Pipe Sizes (NPS) 3/8, 1 ¼, 2 ½, 3 ½, 4 ½, and odd number sizes of equal
and above NPS 5 shall not be used.
1.1.2
Piping size shall be derived from hydraulic calculation based on the following criteria:
a) Velocity
b) Pressure drop
c) Flow induced vibrations (FIV)
1.1.3
For process liquids that contain suspended solid particularly cooling water, the velocity (at
tube side) will depend on the heat exchanger tube material. The recommended cooling water
velocities at tube side are listed as below:
Velocity (m/s)
Tube Material
Minimum
Maximum
2.5
2.0
1.0
5.0
4.5
2.2
Preferred
Velocity for
Design
3.5
2.5
1.5
1.0
1.0
1.0
2.5
3.0
2.2
1.8
2.1
1.5
Titanium
Stainless Steel
Carbon Steel
Cooper nicket
90 Cu/10 Ni
70 Cu/30 Ni
Aluminium Brass
1.1.4
The liquid line sizing criteria for pumps are recommended as below:
Service
Pump Suction
(bubble point)
(Note 1)
Pump Suction
(subcooled)
Line Size,
DN
Maximum
Velocity, m/s
DN ≤ 50
0.6
80 ≤ DN ≤ 250
0.9
300 ≤ DN ≤ 450
1.2
DN ≥ 500
1.5
DN ≤ 50
0.9
80 ≤ DN ≤ 150
1.2
200 ≤ DN ≤ 450
1.5
DN ≥ 500
1.8
Pressure Drop
Normal
Maximum
(kPa/100m)
(kPa/100m)
6
9
23
35
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Service
Pump
Discharge,
P ≤ 50 barg
Pump
Discharge,
P > 50 barg
Reciprocating
Pump
Suction
Line Size,
DN
Maximum
Velocity, m/s
DN ≤ 200
2.5
250 ≤ DN ≤ 300
3.0
350 ≤ DN ≤ 400
3.5
450 ≤ DN ≤ 600
4
(Note 3)
35
45
70
90
2.5
4.5
2
4
6
6
9
9
15 (Note 6)
23 (Note 7)
35 (Note 7)
35
45
1
Discharge
2
Gravity flow
0.6
Thermosiphon
reboiler
(Note 5)
Side-stream
draw-off
(Note 2)
Kerosene jet
fuel
Rich amine
Carbon steel
Caustic soda
Pressure Drop
Normal
Maximum
(kPa/100m)
(kPa/100m)
DN ≤ 50
DN ≥ 80
0.6
0.9
(Note 4)
1.5
2.0
Acid (H2SO4)
(Note 8)
Lean Amine
0.75 (Note 8)
Stripped sour
water
Sour water
3.0
Cooling water
Service water
Demin water,
desalinated
water, service
water, potable
water
3.0
2.5
2.0
4
Notes:
1. Applicable to liquid containing dissolved gas
2. Provide a vertical pipe run of 3 meters minimum from nozzle, same as nozzle size, before
reducing the size of the line
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3. Up to 5 m/s for large lines
4. For line in process units refer to pump suction and discharge criteria.
For loading line, velocity can be increased up to 5 m/s. 50 to 100 m upstream tank inlet,
the velocity shall be reduced to 1 m/s to limit risk associated with static electricity in
conjunction with the presence of flammable air mixture (kerosene can generate light
hydrocarbon which forms flammable mixture when in contact with air)
5. To be check with Heat Exchanger Specialist
6. For main headers
7. For short lines
8. Specific requirement from PTS 12.30.01
The gas line sizing criteria shall comply as below:
Service
Pressure
(barg)
Line
Size, DN
Max
Velocity
(m/s)
Maximum
2
(ρv ,
kg/ms2)
Pressure Drop
Normal
Maximum
(kPa/100m)
(kPa/100m)
6000
(Note 3)
7500
(Note 3)
10000
(Note 3)
-
-
-
-
-
-
30
15000
-
-
-
-
15000
3
8
-
-
90
-
-
-
-
-
2
4.5
Flare system
-
-
0.7 Mach
on flare
header
50000
-
-
Compressor
Suction
i. Reciprocating
ii. Centrifugal
-
-
-
i. 3000
ii. 6000
i. 5
ii. 4
i. 7
ii. 12
Compressor
discharge (Note 4)
-
-
-
-
-
11
Steam, saturated
-
DN ≤ 50
10
15000
(Note 2)
-
Note 1
P < 20
-
60
20 < P ≤
50
-
50
50 < P ≤
80
-
40
P > 80
-
Normal system
(e.g. Column
overhead)
(P> atm)
-
Vacuum System
(e.g. Column
overhead)
Vapor return from
stripper
Gases (general)
(Note 1)
Total
5 mm Hg max
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Service
Pressure
(barg)
-
Steam,
superheated
Vacuum Pipe
Line
Size, DN
DN ≥ 80
DN ≤ 15
Max
Velocity
(m/s)
30
15
-
80 ≤ DN
≤ 200
40
-
DN ≥
250
60
-
-
90
Maximum
2
(ρv ,
kg/ms2)
15000
(Note 2)
15000
(Note 2)
15000
(Note 2)
15000
(Note 2)
-
Pressure Drop
Normal
Maximum
(kPa/100m)
(kPa/100m)
-
Note 1
-
-
Note:
1. Maximum allowable pressure drop for steam lines (continuous operation):
- Pressure below 10 barg: 0.24 bar/km (long headers) / 0.92 bar/km (short headers)
- Pressure below or above 10 barg: 0.92 (long headers) / 2.30 bar/km (short headers)
Limits may be relaxed when sufficient pressure drop is available (e.g. steam let down
stations).
For intermittent operation, the limits may be exceeded on a case to case basis.
2. ρv2 limit of 15 000 kg/ms² can be increased to 25 000 kg/ms² for steam let down stations.
3. Indicative value. Do not exceed 10 000 kg/ms²
4. Compressor vendor requirements, if any, shall prevail
FIV is more predominant in turbulent flow regime piping systems. This type of vibration leads
to displacement of piping system and might lead to damage to pipe support. Table below
shall be followed for the susceptibility to failure of piping systems due to FIV.
1.1.5
Fluid
Negligible
Medium
High
Liquid and multiphase
ρv2 < 10000 kg/ms2
ρv2 ≥ 20000 kg/ms2
Gas
ρv2 < 10000 kg/ms2
or
2
ρ𝑣
10000 𝑘𝑔
<
𝜇𝑔𝑎𝑠 𝑚𝑠 2
√1.10−6
10000 kg/ms2 < ρv2 ≤
20000 kg/ms2
-
ρv2 ≥ 10000 kg/ms2
or
10000 𝑘𝑔
ρ𝑣 2 ≥
𝜇𝑔𝑎𝑠 𝑚𝑠 2
√1.10−6
For GRE / FRP pipe systems, the linear velocity for continuous service of liquids (normal flow
of water / other liquids) should not exceed the limits 2 and 4 m/s respectively.
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1.1.6
The possible particle content in the fluid as well as the reduction of fluid velocity shall be
taken into consideration by the designer of GRE/FRP pipe system. See PTS 12.34.02 (GlassFibre Reinforced Plastic Pipeline and Piping Systems).
1.1.7
Refer PTS 16.52.04 for flare and vent systems sizing.
1.1.8
Refer PTS 16.52.09 to determine the flow pattern of two-phase flow.
1.1.9
Refer Appendix 3 for flow rates (m3/h) of various velocities (m/s), which may be used for
both liquid and gas piping.
1.2
PIPE SIZING CONSIDERATION
1.2.1
Considerations
To determine a suitable pipe size for both the design capacity and conditions such as starting
up, shutting down and regeneration, the following shall be taken into consideration:
i.
The permissible pressure drop
ii.
The possibility of pressure surge occur in the piping system
iii.
The possibility of erosion to occur in the piping system.
iv.
The possibility of piping system to be subjected to vibrations.
v.
The possibility of solids to settle out from the fluid (e.g. in slurry service).
vi.
The type of low pattern of two-phase flow: an intermittent flow pattern shall be
avoided.
The permissible temperature drop if the flu id is highly viscous.
vii.
viii.
ix.
1.2.2
Taking into consideration of the capital expenditure and operating expenditure
of the pumps, compressors and the piping system for economical pipe diameter.
Mechanical strength.
Reynolds number
i.
The product flow can be categorized as laminar or turbulent based on the
Reynolds number.
ii.
The definite value of the Reynolds number indicates the change from one
type of flow to another. For Reynolds number < 2300, the flow in pipe can be
anticipated to be laminar.
iii.
For Reynolds number > 4000, the flow in pipe can be anticipated to be turbulent.
The flow can easily switch from one type to another when Reynolds number is
between 2300 and 4000. The pressure drop could be changed by a factor of 3 or
more.
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iv.
To determine the friction factor for the different types of pipe, the calculated
Reynolds number in Appendix 4 is used.
The Reynolds number is calculated as follows:
𝑅𝑒 =
which:
v.
ρvdi
η
𝑅𝑒 = Reynolds number (dimensionless)
ρ = Density (kg⁄m3)
v = Average linear flow velocity (m/s)
di = Inside diameter of pipe (m)
η = Dynamic viscosity (Pa. s)
For pipe with a circular cross section, equation (1) can be written as:
(1a)
vi.
in which: qm = mass flow (kg/s)
In terms of kinematic viscosity, equation (1) for Re becomes:
(2)
in which kinematic viscosity ᶹ= ᶯ/ᵨ
1.2.3
2
(m /s)
Pressure drop calculations
General
i.
For pressure drop calculations, the formulae given in this section are relevant
to fluids whose density and viscosity are constant along the entire pipe
(normally in the case of liquids). For calculation purposes, pressure drop for
piping components other than straight pipe shall be conveyed as equivalent
lengths (Le) and added to the straight pipe’s length to give the total length (L).
ii.
Table below shows Le for valves and fittings )in which D – nominal pipe diameter):
Type of valve/fitting
Ball valve
Valves
(fully
open)
Gate valve
Globe valve
Reduced bore DN 40 and smaller
Reduced bore DN 50 and larger
Full bore DN 50 and larger
Standard bore
Reduced bore DN 40 and smaller
Straight pattern
Y pattern
Angle pattern
*Le(m)
65 D
50 D
8D
12 D
8D
110 D
65 D
75 D
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*Le(m)
Type of valve/fitting
Check valve
Plug valve
Butterfly valve
Tee-equal
Elbow
Fittings
Bend
Enlargement
Contraction
Miscella
neous
Strainer
Nozzle
Swing type
Ball or piston type, DN 40 and smaller
Dual plate type
Regular pattern
Concentric type
Double offset type
Triple offsite type
Flow straight through
Flow through side outlet
90°, R = 1 1/2 D
45°, R = 1 1/2 D
40 D
110 D
50D
60 D
25 D
50D
60D
20 D
65 D
20 D
16 D
90°, R = 4 D
90°, R = 5 D
180°, R = 4 D
180°, R = 5 D
Sudden, d/D = ¼
Sudden, d/D = ½
Sudden, d/D = ¾
Standard reducer, d/D = ½
Standard reducer, d/D = ¾
Sudden, d/D = ¼
Sudden, d/D = ½
Sudden, d/D = ¾
Standard reducer, d/D = ½
Standard reducer, d/D = ¾
Pump suction Y-type and bucket type
Product outlet nozzle vessel/tank
Product inlet nozzle vessel/tank
14 D
16 D
25 D
28 D
73D
47D
16D
35D
10D
40D
32D
20D
16D
5D
250 D
32 D
64 D
* The Manufacturer's data shall be obtained in critical situations.
iii.
The Manufacturer's data shall be referred to determine the pressure drop of inline instruments, such as vortex or Coriolis flow meters.
iv.
Data from equipment Manufacturer shall be referred to determine the pressure
drop of equipment.
General equation for pressure drop calculation
i.
The pressure drop for a piping system is given by the equation:
(3)
in which: p = pressure drop (N/m2)
 = friction factor (which depends on the Reynolds number and the roughness
factor, ;  and  can be found in Appendix 4.
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L =
di =
v =
 =
ii.
total design length (m)
internal diameter of pipe (m)
average linear flow velocity (m/s)
density (kg/m3)
For pipe having a circular cross section and passing a mass flow qm, equation (3)
becomes:
(3a)
in which:
iii.
= mass flow (kg/s)
To convert pressure drop from N/m2 into metres of liquid, equation (3) can be
written as:
in which:
iv.
qm
g
h
= acceleration due to gravity (m/s2)
= pressure drop (m liquid)
Pressure drop for liquids
The formula given in 1.2.3 shall be applied. For pressure drop across carbon
steel pipes, refer to Appendix 7 and the formulae specified above shall be
applied.
v.
Pressure drop for gas and vapours
Pressure drop will cause the density of fluid to change and there are
possibilities for temperature change. Therefore, the formulae specified in
section 1.2.3 shall not be adhered. In these cases, pressure drop computer
programs should be used to obtain an accurate value.
The following guidelines may be used when an accurate determination of the
pressure drop is not required.
 Use ρ (density) and v (average linear flow velocity) based on either
the inlet or outlet conditions if pressure drop is less than 10% of
the upstream pressure.
 Use ρ (density) and v (average linear flow velocity) as averages of
inlet and outlet conditions if the pressure drop is between 10% and
40% of the upstream pressure.
vi.
Steam pipes
a) For economic sizing of steam pipes, the steam pressure and temperature
conditions of Appendix 5 should be utilized.
b) Steam pipes for conditions not covered in Appendix 5 should be sized in
accordance with Appendix 6.
c) The charts are given for the following steam conditions:


saturated steam at
3.5 bar and 150 °C
superheated steam at 13 bar and 270 °C
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

vii.
superheated steam at 18 bar and 350 °C
superheated steam at 44 bar and 440 °C
Relief valve piping
Refer to PTS 16.52.04 for sizing of relief valve inlet and discharge piping.
1.2.4
Pressure Surge Calculations
i.
Surge occurs when the velocity of fluid changes rapidly, e.g. due to rapid valve
closure, pump trip or start. Under some surge conditions, steep pressure
gradients may arise and it cannot be prevented by appropriate means (e.g. nonslam check valves).
ii.
As a general rule, a pressure surge of 10 bar is produced when there is an abrupt
change of 1 m/s velocity. The length of the pipe as well as the closing speed of
the end valve influences the effects of sudden velocity change.
iii.
In general, pressure surges may be disregarded for pipe with length less than 100
m.
iv.
Screening shall be conducted for liquid surge from valve closure using the
Joukowsky equation, refer to PTS 12.35.01
v.
After a full surge and transient analysis have been performed for surge potential
in a piping system, the following shall be reported to the Owner for approval;
a)
b)
c)
d)
e)
selection of surge scenarios and operational conditions;
final surge pressure analysis;
selection of the most severe surge;
selection of representative piping section;
final static and dynamic stress analysis.
Surge scenarios shall include the following:
i.
rapid valve closure (ESD Valves) with and without pump tripping;
ii.
pump tripping;
iii.
pump start-up;
iv.
pump trip followed by restart.
1.2.5
Maximum possible flow rates shall be covered in the study.
1.2.6
Surge analysis shall be performed for the following systems:
i.
LNG loading and rundown pipes
ii.
LPG loading and rundown pipes
iii.
condensate and crude oil loading pipes
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1.2.7
iv.
cooling water systems
v.
fire water systems
vi.
Single phase liquid
Two Phase Flow
For two phase flow extra precautions shall be taken. The piping system will be subjected to
high excitation forces especially if the flow pattern is intermittent (slug or plug flow) and
these flow regimes shall necessarily be prevented. By having the pressure control valves at
a proper location, these flow regimes can be prevented or reduced.
1.2.8
Sizing criteria for Gas/Liquid Two Phase Flow
a) Erosional Velocity. Flowlines, production manifolds, process headers and other lines
transporting gas and liquid in two-phase flow should be sized primarily on the basis of
flow velocity. Experience has shown that a process of erosion/corrosion has caused the
loss of wall thickness. This process is accelerated by high fluid velocities, presence of
sand, corrosive contaminants such as CO2 and H2S, and fittings which disturb the flow
path such as elbows. When there is no available specific information for
erosive/corrosive properties of the fluid, the following procedure for creating an
“erosional velocity” can be utilized.
(1) The following empirical equation can determine the velocity above which erosion
may occur;
Ve 
c
m
where:
Ve = fluid erosional velocity, feet/second
c = empirical constant
 m = gas/liquid mixture density at flowing pressure and temperature,
lbs/ft3
Industry experience to date indicates that for solids-free fluids values of c =
100 for continuous service and c = 125 for intermittent service are
conservative. Values of c = 150 to 200 may be used for continuous service
for solids-free fluids where corrosion is not expected or when corrosion is
controlled by inhibition or by using corrosion resistant alloys: values up to
250 have been used successfully for intermittent service. Fluid velocities
should be significantly reduced if solids production is expected. Different
values of “c” may be used where specific application studies have shown
them to be appropriate. When assessing pipe wall thickness, periodic surveys
should be considered in the case where solids and/or corrosive contaminants
are present or where “c” values for continuous service are higher
than100.Installation of sand probes, cushion flow tees, and a minimum of
three feet of straight piping downstream of choke outlet should be
considered where solids are anticipated in the design of any piping system.
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(2) The following derived equation may be used to calculate the density of the
gas/liquid mixture :
m 
12409S1 P  2.7 RS g P
198.7 P  RTZ
where:
P = operating pressure, psia.
S1 = liquid specific gravity (water = 1; use average gravity for hydrocarbonwater mixtures) at standard conditions.
R = gas/liquid ratio, ft3/barrel at standard
T = operating temperature, oR.
Sg= gas specific gravity (air = 1) at standard conditions.
Z = gas compressibility factor, dimensionless.
(3) The following derived equation may be used to determine the minimum cross
sectional area required to avoid fluid erosion once Ve is known:
A
ZRT
21.25P
Ve
9.35 
where :
A = minimum pipe cross-sectional flow area required, in2/1000 barrels
liquid per day.
b) Minimum Velocity. To minimize slugging of separation equipment, the
minimum velocity

in two-phase lines should be about 10 feet per second if achievable
where this is especially important in long lines with elevation
changes.
c) Pressure Drop. A simplified Darcy equation from the GPSA Engineering
Data Book (1981 Revision) may be utilized to estimate the pressure drop
in a two-phase steel piping system.
P 
0.000336 fW 2
5
di  m
where:
P = pressure drop, psi/100 feet.
di = pipe inside diameter, inches
f = Moody friction factor, dimensionless.
 m = gas/liquid density at flowing pressure and temperature, lbs/ft3
W = tota1 liquid plus vapour rate, lbs/hr.
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The use of this equation should be limited to a 10% pressure drop due to
inaccuracies associated with changes in density.
If the Moody friction factor is assumed to be an average of 0.015 this
equation becomes:
P 
5  10 6 W 2
di m
5
W may be calculated using the following derived equation:
where:
W = 3180 Qg Sg + 14.6 Q1 S1
Qg = gas flow rate, million cubic feet/day (14.7 psia and 60°F).
Sg = gas specific gravity (air = 1).
Q1 = liquid flow rate, barrels/day.
S1 = liquid specific gravity (water = 1).
It should be noted this pressure drop calculation is an estimate only.
1.2.9
Straight length requirements for flow meters
1.2.10
Straight length requirements for flow meters shall be in accordance with PTS 14.10.02
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APPENDIX 2
: PRELIMINARY SIZING OF PIPES CONTAINING LIQUID (TO BE USED DURING
DETAIL FEASIBILITY STUDY)
Figure A1: Flow Rate 0.1 m3/h to 10 m3/h
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Figure A2.2: Flow rate 10 m3/h to 1 000 m3/h
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Figure A2.3: Flow rate 1 000 m3/h to 10 000 m3/h
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APPENDIX 3
: FLOW RATES FOR PIPES CONTAINING LIQUID OR GAS
SCHEDULE 80
Nominal pipe size, mm
SCHEDULE 40
6
8
10
15
20
25
40
50
65
80
100
150
Inside diameter,
mm 5.48
7.66
10.70
13.84
18.88
24.30
38.14
52.48
62.71
77.92
102.30
154.10
Inside area,
cm2 0.235
0.462
0.906
1.51
2.79
4.64
11.4
21.67
30.89
47.67
82.11
186.3
4.29
7.39
16.77
Velocity (v),
FLOW RATE (m3/h)
m/s
0.25
0.0211
0.042
0.082
0.136
0.251
0.416
1.026
1.95
2.78
0.50
0.0422
0.083
0.163
0.272
0.502
0.832
2.052
3.90
5.56
8.58
14.78
33.55
0.75
0.0634
0.125
0.254
0.408
0.753
1.247
3.078
5.85
8.34
12.88
22.17
50.33
1.00
0.0845
0.166
0.326
0.544
1.004
1.663
4.104
7.79
11.12
17.17
29.56
67.10
1.25
0.1056
0.208
0.408
0.680
1.255
2.079
5.130
9.74
13.90
21.46
36.95
83.88
1.50
0.1268
0.249
0.490
0.815
1.507
2.495
6.156
11.69
16.68
25.75
44.34
100.60
1.75
0.1479
0.291
0.571
0.951
1.758
2.911
7.182
13.64
19.46
30.05
51.73
117.40
2.00
0.1690
0.333
0.653
1.087
2.009
3.326
8.208
15.59
22.24
34.34
59.12
134.20
2.25
0.1902
0.374
0.735
1.223
2.260
3.742
9.234
17.54
25.02
38.63
66.51
151.00
2.50
0.2113
0.416
0.816
1.359
2.511
4.158
10.26
19.49
27.80
42.92
73.90
167.80
2.75
0.2324
0.457
0.898
1.495
2.762
4.574
11.29
21.43
30.58
47.21
81.29
184.50
3.00
0.2536
0.499
0.980
1.631
3.013
4.990
12.31
23.38
33.36
51.50
88.68
201.30
3.25
0.2747
0.540
1.061
1.767
3.264
5.405
13.34
25.33
36.14
55.80
96.07
218.10
3.50
0.2958
0.582
1.143
1.903
3.515
5.821
14.36
27.28
38.92
60.09
103.50
234.90
3.75
0.3170
0.624
1.224
2.038
3.766
6.237
15.39
29.23
41.70
64.38
110.80
251.60
4.00
0.3381
0.665
1.306
2.174
4.018
6.653
16.42
31.18
44.48
68.67
118.20
268.40
4.25
0.3592
0.707
1.388
2.310
4.269
7.069
17.44
33.12
47.26
72.97
125.60
285.20
4.50
0.3803
0.748
1.469
2.446
4.520
7.484
18.47
35.07
50.04
77.26
133.00
302.00
4.75
0.4014
0.790
1.551
2.582
4.771
7.900
19.49
37.02
52.82
81.55
140.40
318.70
5.00
0.4226
0.832
1.633
2.718
5.022
8.316
20.52
38.97
55.60
85.84
147.80
335.50
10.00
0.8452
1.663
3.265
5.436
10.040
16.630
41.04
77.94
111.20
171.70
295.60
671
15.00
1.2680
2.495
4.898
8.154
15.070
24.950
61.56
116.90
166.80
257.50
443.40
1006
20.00
1.6900
3.326
6.530
10.870
20.090
33.260
82.08
155.90
222.40
343.40
591.20
1342
25.00
2.1130
4.158
8.163
13.590
25.110
41.580
102.60
194.80
278.00
429.20
738.90
1677
30.00
2.5360
4.990
9.796
16.310
30.130
49.900
123.10
233.80
333.60
515.00
886.80
2013
35.00
2.9580
5.821
11.430
19.030
35.150
58.210
143.60
272.80
389.20
600.90
1034.60
2349
40.00
3.3810
6.653
13.060
21.740
40.180
66.530
164.20
311.80
444.80
686.70
1182.40
2684
45.00
3.8030
7.484
14.690
24.460
45.200
74.840
184.70
350.70
500.40
772.60
1330.20
3020
50.00
4.2260
8.316
16.330
27.180
50.220
83.160
205.20
389.70
556.00
858.40
1478.00
3355
Table A3.1: Schedule 80 and Schedule 40 Pipes
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SCHEDULE 30
Nominal pipe
size, mm
SCHEDULE 20
SCHEDLE 10
200
250
300
350
400
450
500
600
750
500
600
750
500
600
750
Inside diameter, 205.0
mm
257.4
307.1
336.6
387.4
434.9
482.6
581.1
730.2
489.0
590.6
736.6
495.3
596.9
746.2
Inside area, cm2 330.2
520.5
740.5
889.5
1177
1486
1829
2650
4186
1876
2744
4263
1925
2799
4373
Velocity (v), m/s
FLOW RATE (m3/h)
0.25
29.72
46.86
66.66
80.05
106
133.8
165
239
377
169
246
383
173
253
0.50
59.44
93.72
133.3
160.1
212
267.6
329
0.75
89.16 140.60
199.9
240.1
318
401.4
494
477
754
338
716
1131
507
1.00
118.90 187.40
266.6
320.2
424
535.2
659
955
1508
1.25
148.60 234.30
333.3
400.2
530
1.50
178.30 281.20
399.9
480.3
636
669.0
823
1193
802.8
988
1432
1.75
208.00 328.00
466.6
560.3
2.00
237.80 374.90
533.3
640.4
742
936.6
1152
848
1070
1317
2.25
267.50 421.70
599.9
720.4
954
1204
2.50
297.20 468.60
2.75
326.90 515.50
666.6
800.5
1060
733.3
880.5
1166
3.00
356.60 562.30
799.9
960.6
3.25
386.40 609.20
866.6
3.50
416.10 656.00
933.3
3.75
445.80 702.90
4.00
475.50 749.80
4.25
505.20 796.60
4.50
4.75
493
767
347
505
787
739
1150
520
758
1180
676
986
1534
694
1010
1574
1885
845
1232
1917
867
1263
1967
2261
1014
1497
2301
1041
1516
2361
1670
2638
1183
1725
2684
1214
1768
2754
1909
3015
1352
1972
3068
1388
2021
3148
1482
2148
3392
1521
2218
3451
1561
2273
3541
1338
1646
2386
3769
1690
2465
3835
1735
2526
3935
1472
1811
2625
4146
1859
2711
4218
1908
2779
4328
1272
1606
1975
2863
4523
2028
2958
4602
2082
3031
4722
1041
1378
1739
2140
3102
4900
2197
3204
4985
2255
3284
5115
1121
1484
1873
2305
3341
5277
2366
3451
5369
2429
3536
5509
999.9
1201
1590
2007
2469
3579
5654
2535
3697
5752
2602
3789
5902
1067
1281
1696
2141
2634
3818
6030
2704
3944
6136
2776
4042
6297
1133
1361
1802
2275
2798
4056
6407
2873
4190
6519
2949
4294
6689
535.00 843.50
1200
1441
1908
2408
2963
4295
6784
3042
4437
6903
3132
4547
7083
564.70 890.30
1267
1521
2014
2542
3128
4534
7161
3211
4683
7286
3296
4799
7476
5.00
594.40 937.20
1333
1601
2120
2676
3292
4772
7538
3380
4930
7670
3470
5052
7870
10.00
1189
1874
2666
3202
4241
5352
6584
9544
15076
6760
9860 15340
6940 10104 15740
15.00
1783
2812
4000
4803
6362
8028
9876 14316
22614 10140 14790 23010
10410 15156 23610
20.00
2378
3749
5333
6404
8482 10704 13168 19088
31152 13520 19720 30680
13880 20208 31480
25.00
2972
4686
6666
8005
10603 13380 16460 23860
37690 16900 24650 38350
17350 25260 39350
30.00
3566
5623
7999
9606
12724 16056 19752 28632
45228 20280 29580 46020
20820 30312 47220
35.00
4161
6560
9332 11207
14844 18732 23044 33404
52766 23660 34510 53690
24290 35364 55090
40.00
4755
7498
10665 12808
16965 21408 26336 38176
60304 27040 39440 61360
27760 40416 62960
45.00
5350
8535
11999 14409
19085 24084 29628 42948
67842 30420 44370 69030
31230 45468 70830
50.00
5944
9372
13332 16010
21206 26760 32920 47720
75380 33800 49300 76700
34700 50520 78700
Table A3.2: Schedule 30, Schedule 20 and Schedule 10 pipes
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APPENDIX 4
: FRICTION FACTORS AND ROUGHNESS FACTORS FOR FLOW IN PIPES
Figure A4.1: Schedule 30, Schedule 20 and Schedule 10 pipes
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Figure A4.2: Friction factors for Reynolds number from 2x105 to 108
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Figure A4.3: Roughness Factor
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APPENDIX 5
: SIZING OF STEAM PIPES WITHIN PROCESS PLANT AREAS
Figure A5.1: Saturated steam 3.5 bar (ga), 150°C
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Figure A5.2: Superheated steam 13 bar (ga), 270°c
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Figure A5.3: Superheated steam 18 bar (ga), 350°C
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Figure A5.4: Superheated steam 44 bar (ga), 440°C
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APPENDIX 6
: PRESSURE DROP IN STEAM PIPES NOT COVERED IN APPENDIX 5
Figure A6.1: Density 100 kg/m3 down to 5 kg/m3
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Figure A6.2: Density 5 kg/m3 down to 0.1 kg/m3
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APPENDIX 7
: PRESSURE DROP IN CARBON STEEL WATER PIPES AT 2 °C
Figure A7.1: Flow rate 1 m3/h to 10 m3/h
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Figure A7.2: Flow rate 10 m3/h to 300 m3/h
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Figure A7.3: Flow rate 300 m3/h to 10 000 m3/h
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APPENDIX 8
: VISIBLE LENGTH OF PLATE-TYPE LEVEL GAUGES IN RELATION TO STANDARD
DISPLACER-TYPE LEVEL INSTRUMENTS FOR ASME RATING
CLASSES 150, 300 AND 600
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APPENDIX 9
: ERGONOMIC VALVE POSITIONING
For Ergonomic Valve Positioning, refer to PTS 16.74.02.
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APPENDIX 10 : ADDITIONAL REQUIREMENTS FOR SPECIFIC SERVICES
The following Sections define specific design, fabrication, inspection and testing requirements for
specific process services that supplement the requirements of PTS 15.12.01 and PTS 12.30.05.
10.1
SODIUM HYDROXIDE (CAUSTIC SODA) SERVICE
10.1.1
Design
Sodium hydroxide embrittlement is a type of stress corrosion which is strongly influenced
by temperature. The temperature the pipe may reach in service shall be established in
order to determine the required preventive measures.
The following preventive measures shall be applied (see figure 10.1):
AREA
without heat
tracing
“A"
with heat tracing
"B"
"C"
SPECIAL REQUIREMENTS
None
PWHT of welds (including
attachment welds)
PWHT of cold-formed parts
(which shall be avoided as
far as possible).
PWHT of welds (including
attachment welds)
PWHT of cold-formed parts
(which shall be avoided as
far as possible).
None
PIPING
CLASS
XC103
Temp up
to 150 °C
XC106
Temp up
to 200 °C
XC107
Temp up
to 150 °C
XC106
Temp up
to 200 °C
XC107
XB100
All attachment welds shall be made before any required PWHT is applied.
For steam tracing, PTS 12.30.06 shall apply.
Hot spots due to direct wall-to-wall contact with steam or electric tracing shall be avoided by
fitting spacers (ceramic, glass fibre or filled phenolic resin).
All drawings for the fabrication of carbon steel piping intended for this service shall be clearly
marked "SODIUM HYDROXIDE SERVICE"
Pipe supports shall comply with PTS 12.30.04. Supports shall not be welded to the pipe.
Insulation strips (e.g. glass-fibre material) shall be fitted between pipes and supports.
10.1.2 Fabrication
Gas tungsten arc welding (GTAW) shall be used for piping DN 50 and smaller and for the root
pass of larger size piping.
Required PWHT shall be performed in accordance with ASME B31.3. Cooling shall be
controlled to a maximum rate of 100°C per hour down to 350°C. The complete PWHT cycle
shall be recorded.
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10.1.3 Identification
Piping shall be clearly marked after prefabrication, either by painting or by applying
adhesive tape, to indicate that it is for sodium hydroxide service and to indicate that PWHT
is required for all welds.
The piping class number and the pipe designation shall be painted on each part.
Figure A10.1: Material selection for sodium hydroxide service
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10.2
SULPHURIC ACID SERVICE
10.2.1 Design
Piping shall be sized for a nominal velocity of 0.75 m/s in straight sections and
designed to avoid sudden changes in flow direction, turbulence and extreme changes
in velocity. The use of pipe bends and elbows shall be restricted as far as possible.
Pipe bends shall have a radius of at least 5D (where D is the nominal pipe diameter).
For the fabrication of sweep-in connections, standard long-radius elbows (DN 80 or
larger) shall be used.
Horizontal pipes shall be self-draining, having a slope of at least 1 cm/m.
45° laterals, Y-type or sweep-in junctions shall be used for branches.
Reducers should be avoided. If used, reducers shall be concentric, except in a
horizontal pipe where a concentric reducer could inhibit drainage (i.e. where the
reduced diameter is in the direction of drainage), in which case an eccentric reducer
(bottom flat) should be used. The reduced bore shall match the connecting bore.
In carbon steel systems where turbulence or unacceptably high velocities cannot be
avoided, spool pieces of fully corrosion-resistant unlined material (approved by the
materials engineer of the Owner) or carbon steel lined with fully-resistant material
(PTFE or polypropylene) shall be used (e.g. piping class x8070 or x8160). The length
of such spool pieces shall be at least 20 D.
Flat ring gaskets, with ID dimensions matching the bore of the pipes, shall be used.
The OD dimensions shall be in accordance with ASME B16.21. Gasket thickness shall
be 1.5 mm. Gasket material shall be compatible with sulphuric acid services.
All drawings for the fabrication of carbon steel piping intended for this service shall
be clearly marked "SULPHURIC ACID SERVICE".
10.2.2 Fabrication
GTAW shall be used for piping DN 50 and smaller and for the root pass of larger size piping.
10.2.3 Identification
Piping shall be clearly marked after prefabrication, either by painting or by applying adhesive
tape, to indicate that it is for sulphuric acid service.
The piping class number and the pipe designation shall be painted on each part.
10.3
CHLORINE SERVICE
This Section specifies additional requirements for the design, construction and testing of
carbon steel piping systems for "dry" chlorine, in either the liquid or gaseous phase, at
temperatures between - 35°C and +70°C. "Dry" chlorine is defined as containing less than 150
mg/kg of water.
Chlorine shall be treated as a very toxic substance.
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10.3.1 Design
Piping class 31271 shall be selected for process piping in dry chlorine service, including vent
and relief pipes. PTS 15.10.01 shall also apply.
Only Schedule 80 seamless pipe of minimum size DN 20 shall be used to ensure rigidity and
for protection against mechanical damage resulting in possible leaks.
Piping arrangements shall be as simple as possible, with a minimum of welded or flanged
connections. For pipe of DN 100 and smaller, pipe bending should be applied rather than
using elbows.
Horizontal pipes shall be self-draining with a slope of at least 1 cm/m.
Liquid chlorine has a high coefficient of thermal expansion. Due to thermal expansion a
pressure rise in a locked system could cause a rupture. Therefore the pipe or pipe section
shall have an expansion chamber and a pressure relief valve or rupture disc discharging to a
receiver. The expansion chamber capacity shall be at least 20% of the section volume and
shall be based on a temperature rise of 27°C above the ambient temperature.
The number of field welds shall be minimised.
10.3.2 Fabrication
GTAW shall be used for piping DN 50 and smaller and for the root pass of larger size piping.
All welds shall be inspected in accordance with the "very toxic" category in PTS 12.30.05.
Junctions shall be arranged with the branch 'set into' the run pipe. Adequate weld
preparation shall be made to ensure full penetration of the welds.
10.3.3 Testing and preparation for use
Hydrostatic testing shall be carried out before the system is finally cleaned and dried, so test
gaskets should be used. Prior to pressure testing, gauges, relief valves and other components
which may be damaged should be removed and their openings blocked off.
After the hydrostatic test has been performed, the flange gaskets shall be replaced. Where
required, valves shall be removed to enable drying of the system.
All parts of chlorine piping systems shall be cleaned prior to use since chlorine can react
violently with oil, grease or other foreign materials. See PTS 15.05.01 for cleaning methods.
Before installation, valves shall be tested for seat tightness with clean, dry air at a pressure
of at least 10 bar (ga).
The cleaned and dried piping system shall be pressurized with dry air or nitrogen to 10 bar
(ga) and tested for leaks by applying soapy water to the outside of joints. Afterwards, chlorine
gas should be introduced and the system re-tested for leaks as described below:
The location of a leak in a chlorine-containing system can be detected by the reaction of
ammonia vapour with the escaping chlorine, the reaction giving a dense white cloud. The
most convenient way is to direct the ammonia vapour at the suspect leak employing a plastic
squeeze bottle containing aqueous ammonia. Liquid aqueous ammonia shall not be allowed
to come into contact with piping components.
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If any repair welding is needed after the system has been filled with chlorine, all system piping
shall be thoroughly purged with dry air and checked inside and around the pipe with a gastest tube to verify the absence of chlorine.
Carbon steel ignites in chlorine at 250 °C. A small flow of air shall be maintained during the
welding operation.
10.3.4 Identification
Piping shall be clearly marked after prefabrication, either by painting or by applying adhesive
tape, to indicate that it is for chlorine service.
The piping class number and the pipe designation shall be painted on each part.
10.4
HYDROGEN FLUORIDE SERVICE
This Section addresses materials selection, design, fabrication and testing of piping in
hydrogen fluoride (HF) service.
HF shall be treated as a very toxic substance.
10.4.1 Design
Fine grain carbon steel piping (piping class 31310) shall be used for:
i.
Dry liquid and gaseous HF at ambient temperature.
ii.
Mixtures of HF, hydrocarbons (and some water) as they occur in the HF alkylation
process used for the production of iso-octane and detergent alkylates:
a) hydrocarbons, with up to 33% HF and traces (up to 15 mg/kg) of water,
up to 70 °C
b) hydrocarbons, with up to 4% HF and traces (up to 15 mg/kg) of water, up
to 160 °C
c) hydrocarbons, with traces of HF, up to 200 °C
Monel piping (piping class 36080) shall be used for:
i.
HF, with up to 5% hydrocarbons and 0.5% to 2.0% wt. water, up to 100 °C
ii.
HF, with acid-soluble oil and 0.5% to 2.0% wt. water, up to 145 °C
Expansion bellows shall not be used. All connections shall be welded or flanged; however,
flanged connections shall be reduced to the least possible number to avoid leakages.
All flanges shall be painted with one coat of HF-detecting paint and shall not be insulated.
All valves and instruments shall be located at an elevation of maximum 1 metre above the
working floor for safe and easy handling during operation and maintenance.
To prevent possible deposition of iron fluoride hampering the operation, the valve types shall
be selected as follows:
i.
Globe valves with Monel trim and soft seats (PTFE) for valves which are normally
in the closed position.
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ii.
Plug valves with Monel plug and PTFE sleeve for valves which are normally in the
open position.
All HF service piping shall be installed above grade and shall be self-draining (minimum
slope 1 cm/m) to equipment or low point drains.
Process pipes should be at least DN 25. Drains and vents should be at least DN 20.
Drains and vents shall be connected to a closed system.
All control valves in HF service shall be installed with block valves and a bypass globe valve
and shall have a flush connection on both sides of the control valves.
Level indicators shall be of the magnetic type. Gauge glasses shall not be used.
10.4.2 Fabrication
All welds shall be PWHT (excluding non-pressure attachment welds). Carbon steel welds shall
be PWHT in accordance with ASME B31.3. Monel welds shall be PWHT at a temperature
between 560°C and 580°C for 1 hour.
All welds shall be inspected in accordance with the "very toxic" category in PTS 12.30.05
10.4.3 Identification
Piping shall be clearly marked after prefabrication, either by painting or by applying adhesive
tape, to indicate that it is for HF service and to indicate that PWHT is required for all welds.
The piping class number and the pipe designation shall be painted on each part.
10.4.4 Operation and maintenance
The wearing of protective clothes, gloves, goggles, etc., is particularly critical and it shall be
ensured that all safety instructions are strictly observed.
Before flanges of piping in HF service are disconnected, they shall be neutralized by means
of ammonia or sodium bicarbonate to prevent HF contact with the skin.
Even if severe corrosion is not experienced, fouling and heavy iron fluoride deposits are often
present. Neutralisation of such thick fouling layers is rather difficult and after they have
subsequently been removed mechanically, acidic conditions may again be encountered
underneath due to insufficient neutralisation. If the acidity is such that it is unsafe to continue
work, further neutralisation shall be carried out.
10.5
OXYGEN SERVICE
For gaseous oxygen systems, see PTS 16.52.05
10.6
"WET H2S" / "SOUR" SERVICE
Refer to Appendix 17 for sour service requirement for upstream piping and Appendix 18 for
downstream piping.
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APPENDIX 11
: PIPE SPANS FOR PIPES RESTING ON MORE THAN TWO SUPPORTS
This appendix serves as general guidelines for all piping systems. However, Category 2 and 3 piping
systems as classified in PTS 12.35.01 shall be subjected to further stress analysis.
11.1
CARBON STEEL AND HEAVY WALL STAINLESS STEEL
The data below are applicable to:
i.
Carbon steel pipes, STD wall and heavier, with a maximum temperature of 350
°C.
ii.
maximum temperature of 350 °C.
iii.
Duplex stainless steel pipes, schedule 10S and heavier, with a maximum
temperature of 280 °C.
Maximum Span (mm) (NOTES 1, and 2)
DN
Vapour service
Bare
NOTES:
Insulated (NOTE 3)
Liquid service
Bare
Insulated (NOTE 3)
25
3 850
2 300
3 450
2 250
40
4 750
3 000
4 100
2 800
50
5 350
3 600
4 550
3 300
80
6 550
4 600
5 450
4 200
100
7 500
5 550
6 100
4 900
150
9 150
6 800
7 100
5 800
200
10 500
8 050
7 950
6 700
250
11 800
9 050
8 700
7 400
300
12 900
9 800
9 150
7 800
350
15 150 (NOTE
4)
11 850
10 850
9 300
400
16 250 (NOTE
4)
12 850
11 200
9 750
450
17 250 (NOTE
4)
13 750
11 500
10 150
500
18 200 (NOTE
4)
14 450
11 750
10 400
600
18 950 (NOTE
4)
16 050
12 150
10 950
1.
Spans are based on straight pipe, other configurations shall be multiplied by a shape factor (see sketch
below).
2.
Free draining pipes with a slope less than 1.5 mm/m require an additional check of the span.
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3.
The weight of insulation and sheeting is based on insulation thickness varying from 70 mm for DN 25 to 200
3
mm for DN 600 and a density of 190 kg/m .
Spans limited by deflection. All other spans are limited by longitudinal bending stress.
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11.2
STAINLESS STEEL, SCHEDULE 10S
The data below are applicable to austenitic stainless steel pipes, schedule 10S with a
maximum temperature of 350 °C.
Maximum Span (mm)
Vapour service
DN
Bare
25
40
50
80
100
150
200
250
300
350
400
450
500
600
Notes:
(NOTES 1, 2 and 3)
3 900
4 850
5 450
6 700
7 650
9 400
10 750
12 000
13 000
13 750
14 700
15 650
16 450
18 050
Insulated
(NOTE 4)
2 200
2 800
3 300
4 050
4 800
5 750
6 800
7 600
8 250
8 700
9 450
10 150
11 000
12 700
Liquid service
Bare
3 450
4 000
4 300
4 950
5 300
5 950
6 450
6 950
7 350
7 600
7 750
7 850
8 400
9 050
Insulated
(NOTE 4)
2 100
2 600
3 000
3 500
4 000
4 600
5 200
5 650
6 050
6 300
6 550
6 750
7 300
8 050
1.
Spans are based on straight pipe, other configurations shall be multiplied by a shape factor (see sketch
below).
2.
Free draining pipes with a slope less than 1.5 mm/m require an additional check of the span.
3.
Spans are limited by longitudinal bending stress.
4.
The weight of insulation and sheeting is based on insulation thickness varying from 70 mm for DN 25 to 200
mm for DN 600 and a density of 190 kg/m3.
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APPENDIX 12
12.1
12.2
12.3
: FLANGE FACE ALIGNMENT
TYPES OF ALIGNMENT
Two types of alignment are recognised:
i.
Lateral alignment that is the off-set of the aligned flange centrelines, applicable
to the complete flange set as well as the relative positioning of bolt holes.
ii.
Parallelism of the aligned flange faces, sometimes referred to as angular
alignment.
SET UP PRIOR TO MEASUREMENT
i.
The flanges shall be lined up so that the bolts can be inserted without force.
ii.
A gasket and 25 percent of the bolts (with at least four) shall be inserted. The
bolts shall be uniformly fastened using manual spanners to take out the free
slack, to ensure the real misalignment will be measured.
ACCEPTANCE CRITERIA FOR MISALIGNMENT
12.3.1 Lateral alignment
For standard flanges, the free insertion of the bolts is generally sufficient to demonstrate
acceptable alignment. Lateral alignment may also be checked by laying a straight edge along
the outside diameter of the flange. Measurements should be taken at locations 90° apart
around the flange circumference.
The measured lateral misalignment shall not exceed the following values:
DN
Maximum misalignment
 100
> 100
2 mm
3 mm
Bolt holes shall straddle the natural centreline unless specified otherwise. The maximum
deviation from the required theoretical bolt hole position, as measured along the bolt circle,
shall be 1.5 mm.
12.3.2 Parallelism
Flange face alignment shall be checked by measuring the distance between the mating
flanges of the pre-assembled joint. Measurements shall be taken around the circumference
at equal distances from the centre line (the outside rim of the flange will normally be the
most convenient position).
The difference between the measurements shall not exceed the following values:
i.
ASME B16.5 flanges, all sizes, all ratings:
2.5 mm/m
Note:
This is more stringent than the ASME B31.3 requirement of 5 mm/m but it has been found
realistic to achieve these limits with little or no additional manufacturing effort.
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Table 1 gives these values computed for the flange rim outside diameter.
ii.
ASME B16.47 flanges, all sizes, all ratings:
1.75 mm absolute (regardless of the diameter), measured along the outside
diameter of the raised face.
Tables 2 and 3 give these values computed for measurements along the flange
rim outside diameter.
iii.
Flanged pipe spools
The misalignment tolerances given in (i) and (ii) above apply to pairs of preassembled flanges. For the terminal flange of a pipe spool, the misalignment can
only be measured as the deviation from the design plane. Instead of simply
halving the allowed tolerance for pre-assembled flanges, allowance should be
made for the possibility that the misalignment of an individual flange can be in
either direction and the misalignment of its eventual mating flange may
compensate. Therefore, a statistical factor is appropriate, so that for the terminal
flange of a pipe spool the deviation from the design plane shall not exceed
where M is the allowable misalignment for the pre-assembled flanges as given in
(i) and (ii) above.
iv.
Flanged accessories
Accessories are flanged items which are rigid in themselves (e.g. Valves, strainers
etc.). The individual flange face misalignment from the design plane shall not
exceed 2.5 mm/m. Also, the misalignment of the two flange faces shall not
exceed 2.5 mm/m.
v.
Face alignment for flange-less components (e.g. wafer type control valves,
sandwiched between flanges): Misalignment as per (i) and (ii) above.
vi.
Nozzle faces on static equipment.
Alignment of nozzle flange face with the indicated plane shall be within 0.5° in
any direction.
NOTE:
vii.
This tolerance is in line with that specified in PTS 12.20.04 and PTS 16.52.06
Flanges connecting to rotating equipment (pumps, compressors etc)
The flange face alignment check shall be performed with bolting inserted loosely, and the
acceptance criteria shall be as given below:
Flange diameter (DN)
< 300
300 to 600
 600
Maximum misalignment at OD of flange
0.2 mm
0.3 mm
0.5 mm
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Table A12.1: ASME B16.5 flanges, all sizes, all ratings
NOTE:
The above figures are the practical implementation of the tolerances specified in the relevant rotating equipment
PTS (i.e. 0.05° in all directions).
Maximum flange face misalignment:
i.
for a pre-assembled joint, maximum difference in measured values = 2.5 mm/m
ii.
for an individual flange, maximum difference to design plane =
mm/m
This results in the following figures for measurements taken at the outer rim of the flange:
Pre-assembled joint
Individual flange compared to design plane
M
(mm)
size
(mm)
Rating
size
Rating
DN
150
300
600
900
1500
2500
DN
150
300
600
900
1500
2500
15
0.22
0.24
0.24
0.30
0.30
0.33
15
0.16 0.17
0.17
0.21
0.21
0.24
20
0.25
0.29
0.29
0.33
0.33
0.35
20
0.17 0.21
0.21
0.23
0.23
0.25
25
0.27
0.31
0.31
0.37
0.37
0.40
25
0.19 0.22
0.22
0.26
0.26
0.28
40
0.32
0.39
0.39
0.44
0.44
0.51
40
0.22 0.27
0.27
0.31
0.31
0.36
50
0.38
0.41
0.41
0.54
0.54
0.59
50
0.27 0.29
0.29
0.38
0.38
0.42
80
0.48
0.52
0.52
0.60
0.67
0.76
80
0.34 0.37
0.37
0.43
0.47
0.54
100
0.57
0.64
0.68
0.73
0.78
0.89
100
0.40 0.45
0.48
0.52
0.55
0.63
150
0.70
0.79
0.89
0.95
0.98
1.21
150
0.49 0.56
0.63
0.67
0.70
0.85
200
0.86
0.95
1.05
1.17
1.21
1.38
200
0.61 0.67
0.74
0.83
0.85
0.98
250
1.02
1.11
1.27
1.37
1.46
1.68
250
0.72 0.79
0.90
0.97
1.03
1.19
300
1.21
1.30
1.40
1.52
1.68
1.91
300
0.85 0.92
0.99
1.08
1.19
1.35
350
1.33
1.46
1.51
1.60
1.87
350
0.94 1.03
1.07
1.13
1.32
400
1.49
1.62
1.71
1.76
2.06
400
1.06 1.14
1.21
1.25
1.46
450
1.59
1.78
1.86
1.97
2.29
450
1.12 1.26
1.31
1.39
1.62
500
1.75
1.94
2.03
2.14
2.46
500
1.23 1.37
1.44
1.52
1.74
600
2.03
2.29
2.35
2.60
2.92
600
1.44 1.62
1.66
1.84
2.07
NOTE:
Blank cells indicate size rating values not standardized in ASME B16.5.
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Maximum flange face misalignment at raised face OD:
i.
for a pre-assembled joint, 1.75 mm/m
ii.
for individual flange, maximum difference to design plane,
mm
This results in the following figures for measurements taken at the outer rim of the flange:
Pre-assembled joint
size
Individual flange compared to design plane
ASME B16.47, series A
size
ASME B16.47, series A
DN
150
300
600
900
DN
150
300
600
900
650
1.93
2.06
2.14
2.35
650
1.37
1.46
1.51
1.66
700
1.92
2.05
2.13
2.36
700
1.36
1.45
1.50
1.67
750
1.91
2.05
2.13
2.36
750
1.35
1.45
1.50
1.67
800
1.91
2.05
2.12
2.34
800
1.35
1.45
1.50
1.65
850
1.91
2.04
2.14
2.32
850
1.35
1.44
1.51
1.64
900
1.90
2.03
2.10
2.29
900
1.35
1.44
1.49
1.62
950
1.92
2.02
950
1.36
1.43
1000
1.90
2.00
1000
1.35
1.41
1050
1.90
2.00
1050
1.34
1.41
1100
1.89
1.99
1100
1.34
1.41
1150
1.90
2.01
1150
1.34
1.42
1200
1.89
1.99
1200
1.34
1.41
1250
1.88
1.98
1250
1.33
1.40
1300
1.88
1.98
1300
1.33
1.40
1350
1.88
1.98
1350
1.33
1.40
1400
1.88
2.01
1400
1.33
1.42
1450
1.90
2.01
1450
1.34
1.42
1500
1.89
1.99
1500
1.33
1.41
Table A12.2
NOTE:
: ASME B16.47, series A, all sizes, all ratings
Blank cells indicate size rating values not standardized in ASME B16.47.
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Maximum flange face misalignment at raised face OD:
i.
for a pre-assembled joint, 1.75 mm/m
ii.
for individual flange, maximum difference to design plane,
mm
This results in the following figures for measurements taken at the outer rim of the flange:
Pre-assembled joint
size
Individual flange compared to design plane
ASME B16.47, series B
size
ASME B16.47, series B
DN
150
300
600
900
DN
150
300
600
900
650
2.03
2.27
2.37
2.54
650
1.44
1.60
1.68
1.79
700
2.03
2.26
2.35
2.56
700
1.43
1.60
1.66
1.81
750
2.01
2.23
2.31
2.51
750
1.42
1.58
1.63
1.78
800
2.03
2.20
2.28
2.52
800
1.44
1.56
1.62
1.78
850
2.01
2.19
2.26
2.53
850
1.42
1.55
1.60
1.79
900
2.00
2.17
2.25
2.50
900
1.41
1.54
1.59
1.77
950
2.02
1.99
950
1.43
1.41
1000
2.01
2.00
1000
1.42
1.41
1050
1.97
1.98
1050
1.40
1.40
1100
1.97
1.98
1100
1.40
1.40
1150
1.96
1.99
1150
1.39
1.41
1200
1.95
1.97
1200
1.38
1.39
1250
1.95
1.97
1250
1.38
1.39
1300
1.95
1.96
1300
1.38
1.39
1350
1.95
1.98
1350
1.38
1.40
1400
1.94
1.97
1400
1.37
1.39
1450
1.94
1.95
1450
1.37
1.38
1500
1.94
1.95
1500
1.37
1.38
Table A12.3
NOTE:
: ASME B16.47 flanges, series B, all sizes, all ratings
Blank cells indicate size rating values not standardized in ASME B16.47.
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APPENDIX 13
: TYPICAL ARRANGEMENT OF CONTROL VALVE MANIFOLD
Preferred construction for situations where:
 The size of the upstream or downstream
ping is DN 80 or larger
Preferred construction for situations where:
 The size of the upstream/downstream
piping is DN 50 or smaller
 Required for proper supporting
NOTES:
1. Sufficient clearance shall be provided above and below the control valve for dismantling purposes.
2. The by-pass valve shall not be located directly above the control valve.
3. The by-pass line shall not be located directly above control valve for line size DN 100 and above.
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APPENDIX 14
: MINIMUM REQUIRED WALL THICKNESS
Wall thickness shall be as per piping class for specific services.
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APPENDIX 15
: SUPPLEMENTARY REQUIREMENTS APPLICABLE TO UPSTREAM FACILITIES
Note: Appendix 15 is applicable for offshore exploration and production facilities (platform
piping including piping on FPSO type of facilities), onshore exploration and production
facilities and for all terminals, irrespective of piping class PTS 12.31.02 and/or PTS 12.31.01.
This requirement excludes non metallic piping material.
The following clause numbers are supplementary to the main text of this PTS.
9.4
PRESSURE TESTS FOR UPSTREAM FACILITIES
General Requirements
All fabricated piping spools and field welds shall be subjected to a hydrostatic or pneumatic
pressure test.
All piping systems shall also be subjected to reinstatement (before service) leak test by using
either water or air or nitrogen or helium or combination of nitrogen and helium, depending
on fluid in service.
Testing shall be in accordance with the latest revision and addenda of ANSI/ASME B 31.3 as
amended by the requirements of this specification.
Contractor shall submit instructions for each pressure test and for each leak test for Owner’s
approval prior to execution of the tests at site. These instructions shall consist of pressure
test, flowsheets/P&ID , isometrics and, where necessary, piping plans/elevations indicating
the following:
i.
Test limits and scope.
ii.
Flushing routes and method.
iii.
Position, identification number and status of all blanks, spades, spectacle blinds,
valves, vessels and instruments, etc.
iv.
Identification of all system components which must be removed for the test.
v.
Vent and drain points.
vi.
Test pressure, test medium, test duration, platform system, line and valve
identification.
vii.
Position of fill and pressurisation points.
viii.
Position of test equipment and any temporary attachments to the system.
ix.
Position and details of any temporary supports which may be required.
x.
General area locations within which the test is confined.
xi.
Areas where waivers from the requirements of this specification will be required.
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All identified pressure tests shall be recorded by spool or system on a pressure test overview
sheet package which shall be used as a control document for all testing.
Where applicable, the pressure test instructions shall be accompanied with the relevant
signed construction check sheet.
Contractor shall identify all system high and low points and ensure that all such points are
provided with vent or drain connections as applicable.
Each line test shall be witnessed and approved by the Owner and test results recorded by the
Contractor.
All atmospheric open drain/ vent lines and closed drain lines shall also be pressure tested in
accordance with this document.
The hydrostatic test medium should be fresh water. For water quality for different pipe
material, refer to PTS 12.02.01 section 3.0. In certain cases, it is permissible to use non-volatile
hydrocarbons such as lubricating oil or diesel with prior Owner approval.
If test water is removed from a system following testing but the system is not put into service
within one month, it shall be dried below dew point, or purged and filled to a minimum
positive pressure of 0.2 barg with an inert gas such as nitrogen.
To avoid water contamination, pneumatic tests should be carried out on the following piping
systems:
i.
diesel fuel
ii.
instrument air/instrument gas
iii.
fuel gas (downstream of main fuel gas scrubber)
iv.
lubricating oil lines
Hydrostatic testing of the above piping may be permitted if the lines are thoroughly dried
afterwards using dry instrument air. Pneumatic tests for lines other than those given above
shall not be carried out without prior approval of the Owner.
9.4.1
Pressure Test
Hydrostatic pressure testing for new piping shall be carried out in accordance with ASME
B31.3 section 345.4.
Hydrostatic pressure testing for existing piping shall be carried out at 1.5 x MAWP(system
design pressure) or 1.5 x MAOP which shall be discussed and agreed upon with the Owner.
For launcher / receiver piping design to ASME B31.8/31,4, the hydrostatic test pressure shall
follow the pipeline test pressure.
Pneumatic pressure testing in lieu of hydrostatic testing may be performed at pressures
determined in accordance with ANSI/ASME B31.3 section 345.5, subject to approval from
Owner.
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In exception circumstances, for example the riser tie-in weld between topsides / pipeline, and
the piping butt-weld connection(s) between platform / bridge piping, where the weld cannot
be pressure tested, without retesting these joints can be considered as closure weld as
defined in ASME B31.3. All these joints shall be considered as golden welds. In such cases
golden weld and NDT procedures shall be prepared by Contractor and approved by Owner.
Wherever the final closing weld is through flange joint, it shall be re-instatement leak tested
or alternatively camprofile gasket be used for local leak testing. All such details shall be
agreed during detail engineering stage.
9.4.2
Duration Of Pressure Test
The holding time at the test pressure shall be of one hour minimum.
If during the period of the pressure test, any faults are discovered and repaired, repeat test
shall also be for a minimum duration one hour.
For definition purposes the pressure test shall be deemed to commence on satisfactory
completion of flushing, filling and stabilisation of system test pressure.
The test procedures for both hydrostatic and pneumatic shall be approved by Owner.
9.4.3
Preparation of Facilities for Testing
Preparatory work shall generally be in accordance with para 345.3 of ANSI/ASME B31.3 but
the following additional requirements shall be applicable.
All lines to be tested shall be clean externally. All field welded joints shall be left unpainted
until completion of testing.
All component parts of the system shall be examined and checked to ensure that they are
compatible with the design specifications and approved drawings. Particular care shall be
taken to ensure that the pressure rating of all system components is suitable for the specified
test pressure.
The system to be tested shall be prepared to the following status prior to testing.
i.
Blinds at the system extremities shall be set in the closed position. All other
system blinds shall be set to the open position to facilitate flushing and filling.
ii.
All instruments and relief valves or any other equipment not to be included in the
test shall be removed.
iii.
Check valves shall be defeated by reversing the valves, removing their plates or
replacing the valve with a spool as indicated on the test diagram.
iv.
All isolation valves shall be set to the applicable position which shall be fully open
for flushing/filling and half open for pressure testing.
v.
All orifice plates and filters shall be removed.
vi.
All off-line instrument isolation valves and sample/chemical injection point
isolation valves shall be removed and the connection blinded off for leak testing.
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All lines shall be flushed with water at a sufficiently high velocity to ensure removal of internal
debris. A minimum flushing velocity of 3 m/s shall be used. Flushing shall be effected from a
suitable system high point to a suitable low point; flanges shall be opened and valves removed
as necessary to ensure that the piping is flush thoroughly.
Flushing shall be carded out to the satisfaction of the Owner. All flushing water shall be
thoroughly drained from the system as soon as flushing is completed unless the flushing media
is identical to the hydrotest media in which case the system need not be drained following
flushing.
On completion of flushing a check shall be carried out to ensure that all system components
are configured as required for the pressure test.
Calibrated pressure and temperature recorders and indicators shall be installed. The
Contractor shall ensure that calibration certificates are available for each indicator and
recorder. Master test gauges, local ambient air temperature sensors and test media
temperature sensors and pressure recorders shall be provided. The recorders shall be capable
of registering a change in pressure of 1.0%. It shall also be ensured that correctly ranged charts
are provided and that sufficient ink is available for the duration of the test. A dead-weight
tester shall be made available for calibrating hydrotesting equipment.
All test equipment shall be recalibrated immediately prior to the pressure testing phase of any
project but the maximum duration between recalibration shall be one month.
The Owner reserves the right to request that test recorders be recalibrated at any time if has
reasonable grounds to believe that calibration may have been adversely effected e.g. by
impact damage during transportation.
The pressure recorder calibration shall be such that the test pressure is approximately 70% of
full scale. Recorder timer duration shall be a maximum of eight hours and preferably four
hours.
9.4.4
Pressure Testing Procedure
For pressure tests of piping system, refer to PTS 12.30.05.
9.4.5
Reinstatement Testing
Upon completion of pressure testing for the piping, all the in-line and attached instruments &
accessories shall be assembled to the piping for performing the reinstatement testing. The
piping system shall be filled with a suitable test medium depending on the service as per below
table. Where a water contamination is to be avoided, it is permissible to use non-volatile
hydrocarbon such as lubricating oil or diesel or pneumatic (nitrogen or combination of
nitrogen and helium).
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Test Medium
Test Pressure
Leak Detection
Method(note5)
99%N2+1%H
e
35% of Design
Pressure
(note 1,2)
Helium Mass
Spectrometry –
Detector Probe
Technique (Note 3)
2
Hot Oil, Glycol, Diesel, Lube
Oil, Nitrogen
Nitrogen
35% of Design
Pressure
(note 1,2)
Bubble Test-Direct
Pressure Technique
(Note 3)
3
Instrument Air, Utility Air,
Dry Air
35% of Design
Pressure
(note 1,2)
Bubble Test-Direct
Pressure Technique
(note 3)
Water
95% of PSV set
pressure or 100%
system design
pressure if there
is no PSV (note 1)
Pressure Loss/Visual
Dry Air/
Nitrogen
Operating
Pressure
Bubble Test-Direct
Pressure Technique
(note 3)
Water
Static head
Visual
No
Service
1
FWS, Un-stabilized and
Stabilized crude/condensate
, Hydrocarbon Gas
(Wet/Dry), Hydrocarbon Gas,
Fuel Gas, Utility Gas,
Instrument Gas
4
5
6
Firewater, Seawater,
Produced
water, Potable/Service/
Cooling Water, Closed Drain ,
Stabilized Crude/Condensate
HP/LP Flare (Wet/Dry)
Header Downstream of the
Knock Out Drum
Open Drain (Hazardous/nonhazardous)
Notes:
1. The detailed reinstatement test procedure shall be prepared by the Contractor for each
Project complete with the test P&IDs, JSA etc., in-line with ASME PCC-2 (Part-5, Article
5.1, clause 6.3), for obtaining PETRONAS Project Approval prior to performing this test.
2. Design Pressure shall mean PTS piping class design pressure at ambient temperature.
3. Leak detection method shall be as per ASME Code Section V, Article 10.
Table A9.4
: Reinstatement Test Medium, Pressure and Leak Detection Method
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9.4.6
Leak Testing of Valves
Onshore testing
Valves provided with a manufacturers test certificate shall also be subjected to further leak
testing in accordance to API 6D (Site Acceptance Test) prior to in-situ installation. Valve in
packaged item shall be also Site Acceptance Tested which shall be done by the package
vendor. All valve shall be leak tested, Owner approval shall be obtained for any deviation.
Note:It may be assumed that any valve which is procured through the PMRC system will have a valid test certificate.
This is also true of valves purchased to PMRC specifications by a third party on behalf of the Owner (for example
fabrication or installation contractors) provided that their documentation system is traceable.
Any valve which has a test certificate but which has been on the shelf for a period exceeding
one year shall be subjected to a further hydrostatic test. Hydrostatic test pressure and
acceptance criteria shall be as per API 6D for valves purchased to API 6D, and as per BS 6755
part 1 for valves purchased to BS 5351.
9.4.7
Test Checklist
For all pressure test, Contractor shall prepare a pressure test overview check list which shall
be signed by both the Owner’s site representative and the Contractor’s representative to
demonstrate compliance with the test procedure.
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APPENDIX 16
16.1
: NON-WELDED PIPE JOINT USING PRELOAD METHOD FITTINGS
MATERIAL SUITABILITY
16.1.1 Carbon Steel
Non-welded pipe joint using preload method fittings for carbon steel components as per
ASTM A106 Grade B or ASTM A53 Grade B may be used with uncoated carbon steel pipe at
the preload area. If other grade of carbon steel material to be used, it shall be subjected to
qualification test and Owner approval.
After installation, the preload fittings should receive the same surface preparation and coating
system as the remainder of the piping system. The carbon steel fittings shall be properly
preserved to protect against deterioration during its shelf life.
16.1.2 Stainless Steel
Non-welded pipe joint using preload method fittings for stainless steel components may be
used with ASTM A312 pipe of the following grades: TP304, TP304L, TP316 and TP316L.
The fittings and pipes shall be of the similar material.
16.1.3 Other Materials
Use of preload fittings for joining dissimilar materials shall be investigated and advised by the
preload fittings vendor and shall be reviewed by PETRONAS Piping Technical Authority.
Do not install preload fittings on coated pipe.
16.2
PRELOAD FITTINGS STANDARD APPLICATIONS
All the preload fittings shall be free from foreign material before installation including
corrosion scale. The inner surface shall be smooth and no sign of metal loss.
Preload fittings are qualified for use per ASME B31.1 and B31.3, and are suitable for new
piping installation and in-service piping, and are suitable for all services except Severe Cyclic
services; or High Pressure services; and subjected to limitations specified herein:
16.2.1 Allowable Pipe Sizes and Schedules
Carbon steel preload fittings can be used on 1/2” NPS (DN15) thru 4” NPS (DN100) carbon
steel pipe from schedule 40 to schedule 160.
Stainless steel preload fittings can be used on 1/2” NPS (DN15) thru 3” NPS (DN80) stainless
steel pipe from schedule 10S to schedule 80S.
All preload fittings follow standard dimension as specified in ASME B36.10 and B36.19 (for
pipes), ASME B16.9 for tees and elbows, and ASME B16.5 for flanges.
16.2.2 Allowable Pressure Limits
Preload fittings are to be used in services within the allowable pressure-temperature rating as
per ASME B16 standards, and material of construction shall be compatible to the fluid
contained. The depressurization condition of the pipe shall also be checked for suitability of
preload fittings. The allowable working pressure of preload fittings on qualified matching pipe
sizes and wall thickness (schedules) under the respective rules of ASME B31.1 and B31.3 shall
be provided by manufacturer.
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16.2.3 Temperature Limits
Except for cold and cryogenic applications, preload fittings can be used within normal
temperature range of the applicable piping material class, but subject to an upper
temperature limit of 343oC (650oF) for carbon steel and 426.7oC (800oF) for stainless steel
materials.
As per industrial practices and experiences, the use of preload fittings is limited to -51.1oC (60oF), applications below -51.1oC (-60oF) should be evaluated on a case-by-case basis and
subjected to Owner approval.
16.2.4 Stress Intensification Factor (SIF)
For those exceptional cases where a flexibility analysis must be performed on small bore
piping, the stress intensification factor (SIF) for preload fittings shall be: SIF = 1.3. This value
shall be confirmed by preload fittings vendor.
16.2.5 Limitations Using Coated or Galvanized Pipe
Preload fittings shall not be used on coated pipe (except that installation on pipe with a coat
of inorganic zinc of 3.0 mils or less is allowed.) Verification of coating and thickness is
mandatory.
16.2.6 Limitations in Corrosive Services
Preload fittings are not recommended for use in highly corrosive piping systems. General
guideline with respect to required corrosion allowances are as follows:
i.
Carbon steel preload fittings are acceptable if the required corrosion allowance is
1.6mm (0.063”) or less.
ii.
Note that preload fittings use is based on the actual corrosion allowance required
for the system and not the specified corrosion allowance provided by the normal
material class used for the piping system service.
iii.
If a corrosion allowance greater than that specified above is required, refer to
PETRONAS Piping and Corrosion Technical Authority for guidance.
16.2.7 Considerations for Crevice Corrosion and Protection
Preload fittings provide a location for crevices corrosion similar to that of socket-welding and
threaded components. The use of preload fittings in systems where crevices are undesirable
shall be avoided.
The existence of crevices is also a consideration for cleanliness around lube and seal oil circuits
for machinery, and other systems where cleanliness of the system is important.
The use of anaerobic/ ceramic steel reinforced polymer sealants may be considered to protect
the preload fittings joint from crevice corrosion. However the approval shall reside with the
PETRONAS Piping Technical Authority
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16.2.8 Considerations on Stress Corrosion Cracking for Radially Compressed Fittings
During preload fittings installation, the pipe wall is radially compressed, first elastically and
then plastically by the swaging action of the fitting. This swaging action creates residual tensile
stresses circumferentially in the inside diameter of the pipe under the sealing lands of the
fitting body. These stresses may be sufficient enough to cause stress corrosion cracking (SCC)
of the pipe in certain services such as services with the presence of H2S (sour), chloride and
caustic services where PWHT is required on the welded part of the piping.
Where the above-mentioned SCC is anticipated, all preload fittings carbon steel and stainless
steel, together with the adjoining pipes, shall comply with NACE MR 0175/ISO 15156 material
requirement. In addition, all components shall be qualified for use by performing sampling lab
test as specified in clause B.3 of NACE MR 0175/ISO 15156.
16.2.9 Service Limitations
There are several general service categories where preload fittings shall not be used. They
include the following categories:
i.
ASME B31.3, Category M service.
ii.
ASME B31.1, boiler external piping.
iii.
Furnace or heater internal piping.
iv.
Internal pipe in a jacketed system.
v.
Cyclic services.
vi.
As the first connection from an ASME pressure vessel.
There are several specific services where preload fittings shall not be used. They include the
following services:
i.
Amines (applies to carbon steel components only)
ii.
Anhydrous Ammonia (applies to carbon steel components only)
iii.
Caustic, where PWHT is required (unless qualified by NACE MR 0175/ ISO 15156
test)
iv.
Chlorine (unless qualified by NACE MR 0175/ ISO 15156 test)
v.
Chloride Brines e.g. calcium or sodium brines (unless qualified by NACE MR 0175/
ISO 15156 test)
vi.
Chloride-contaminated Water (applies to stainless steel components only)
vii.
Clean Hydrogen (carbon steel fittings may be used if the conditions are below the
Nelson Curve limits)
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viii.
Hydrogen Sulfide (unless qualified by NACE MR 0175/ ISO 15156 test)
ix.
LPG
x.
Mineral Acids (hydrochloric, hydrofluoric, sulfuric, and phosphoric)
xi.
Organic Acids (e.g. acetic acid)
xii.
Sour Hydrogen
xiii.
Sour Water
xiv.
Other Corrosive Fluids
16.2.10 Service Acceptable for Preload Fittings Application
The following lists of services have been approved and are acceptable for using preload
fittings when specified:
i.
Flare Systems
ii.
Foam Systems
iii.
Hydraulic Fluids
iv.
Hydrocarbon Services
v.
Hydrocarbon Solvents
vi.
Instrument Piping
vii.
Lubricating Oils/Seal Oils (acceptable only if socket-welding or threaded joints
would be acceptable, i.e. no crevice corrosion or oil contamination concerns – see
paragraph 5.7)
viii.
Process Streams (with no Section 5 restrictions)
ix.
Product Loading Lines
x.
Sample Stations
xi.
Steam up to 20.7 Bar(g)
xii.
Steam Condensate
xiii.
Utilities (Air – process, instrument, breathing, industrial, plant, utility, & yard; Gas
– blend, fuel, pilot, & natural; Nitrogen; Water – domestic or potable, cooling
supply and return, fire, industrial, re-circulated, & utility)
xiv.
Vent Systems
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16.2.11 Petrochemical Industry Applications
The following paragraph lists additional specific systems in which preload fittings have been
used at various facilities within the petrochemical industry. Listing of these services does not
provide blanket approval, only a listing of possible services that may be considered.
Additional Petrochemical Industry Service Applications:
Acetone
Acetonenitril, dry
Adipic Acid
Acrylic Acid
Ammonia/Water
Butane Diol
Butyl Butylene Vapor
Diesel Fuel
Diluent
Di-Isobutylene
Di-Methyl Foramide
Dimenthylacetamide
Dowtherm
Epoxy Resin
Ethyl Benzene
16.3
Ethylene
Formaldehyde
Ethanol
Formalin
Stream
Glycerin
Heptane
Hexane
Hydrofluoric Vapors
Hydrogen Peroxide
Hydroxamine
Isopropyl Alcohol
Ketone
Lime Slurry
Methyl Chloride
Mineral Spirits
Nitric Acid
Methanol
Orthene Waste
Gasoline Blend
Phenyl Isocyanate
Polyol
Potassium Hydroxide
Propane
Sodium Hydroxide
Solvent Delivery
Tertiary Butyl Alcohol
Tetrahydrofuran
Toluene
Phenol
NON-STANDARD REPAIR APPLICATIONS
Because of the ‘no hot-work’ and ‘quick-fix’ benefits of preload fittings, it may be desirable to
adopt this technology for connecting pipes as a “welded-equivalent” for repair/ maintenance
purposes, tie-ins, modifications or replacement of badly damaged/corroded pipe sections and
ageing pipes; with appropriate review and approval by PETRONAS Technical Authority.
Under this application, it is Owners prerogative to consider each installation as a temporary
repair solution or a permanent installed solution, on a case by case basis. If the installation is
for temporary, it shall be stewarded to assure that it is replaced at the earliest opportunity.
All appropriate personnel (unit, inspection, mechanical, etc.) shall be made aware of the
installation to aid in monitoring it until replacement has been completed. If the installation is
for permanent, it shall be treated same as piping system in terms of inspection and
maintenance.
Preload fittings shall not be installed, even on an emergency or temporary basis, when they
do not meet all other criteria specified in Section 4.1 and 4.2 of this standard, except as
modified above for exceptions with regard to corrosion rates.
16.4
MINIMUM INSTALLATION REQUIREMENT
When the use of preload fittings has been specified, they should be installed in accordance
with vendor Installation Procedure, by trained and certified personnel. All hydraulic systems
that required for installation of preload fittings shall be applied at the same time.
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16.4.1 Post-Installation Inspection
When preload fittings have been installed, it is Owner’s responsibility to ensure that ALL
preload fitting joints are subjected to visual inspection based on preload fittings vendor’s
visual check procedure.
For service where minor internal corrosion is expected, radiographic testing may be used as a
method for periodic inspection to monitor the internal condition around preload fitting joints.
16.4.2 Post-Installation Testing
Pressure-testing requirement for all piping joints that is using preload fittings shall follow the
pressure-testing requirement of the correlated service.
In case where pressure-testing requirement for the service is not-specified, or unknown,
testing of preload fitting joints shall be governed by testing requirement of a normal welding
joint as specified in ASME B31.1 or ASME B31.3, whichever is applicable.
16.5
MATERIAL CERTIFICATION
Materials certification shall be in accordance with EN 10204 and / or ISO 10474 of Type 3.1.
Materials certificate Type 3.2 shall be required for sour service and CRA materials.
16.6
COMPONENT MARKING
16.6.1 Preload fittings manufactured shall be marked by the Manufacturer as specified in
paragraph 16.6.4.
16.6.2 Additional project related markings as desired by the Manufacture and/or as requested by
the owner shall be included.
16.6.3 Marking shall be applied by low stress stamp or marking tool (engraved or embossed) on the
preload fittings. The markings shall be easily readable after installation.
16.6.4 All preload fittings shall be permanently marked with:
16.7
i.
Manufacturer identification (logo/symbol)
ii.
Heat Number
iii.
Size, Rating and Material
OTHER UNLISTED MECHANICALLY ATTACHED FITTINGS FOR PIPING SYSTEM
Refer to PTS 12.30.11.
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APPENDIX 17
17.1
: SOUR SERVICE REQUIREMENT FOR OFFSHORE PIPING
SCOPE
This specification establishes the minimum requirements for sour service requirements for
offshore piping.
17.2
SPECIFIC ABBREVIATIONS
No
Abbreviation
1
ASME
Description
American Society of Mechanical Engineers
2
ASTM
American Society for Testing and Materials
3
CE
Carbon Equivalent
4
CRA
Corrosion Resistant Alloy
5
CTR
Crack Thickness Ratio
6
CLR
Crack Length Ratio
7
CSR
Crack Sensitivity Ratio
8
FCAW
Flux Core Arc Welding
9
FN
Ferrite Number
10
GHSC
Galvanically Induced Hydrogen Stress Cracking
11
HAZ
Heat Affected Zones
12
HIC
Hydrogen Induced Cracking
13
ISO
International Standard of Organization
14
MT
Magnetic Particle Testing
15
NDT
Non-Destructive Testing
16
NACE
National Association of Corrosion Engineer
17
PWHT
Post Weld Heat Treatment
18
PT
Penetrant Testing
19
PTS
PETRONAS Technical Standards
20
SSC
Sulphide Stress Cracking
21
SCC
Stress Corrosion Cracking
22
SOHIC
Stress Oriented Hydrogen Induced Cracking
23
TMCP
Thermal/Mechanical Controlled Process
24
WPS
Welding Procedure Specification
25
WPQR
Welding Procedure Qualification Record
26
WPQT
Welding Procedure Qualification Tests
Table 17.1: Abbreviations
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17.3
DEFINITION AND SUSCEPTIBILITY TO SOUR SERVICE
“Sour” service is the term used for environments containing sufficient H2S to cause cracking
of materials by the mechanisms addressed in NACE MR0175/ISO 15156 when the following
conditions exist:
i.
H2S concentrations are
a) For gas-containing systems the partial pressure of H2S exceeds 3.0 mbar
(0.05 psi) (abs), or;
b) For liquid containing systems when the concentration of H2S is higher
than that occurring in a liquid equilibrium with a gas containing H2S at a
partial pressure of 3.0 mbar (0.05 psi) (abs); and
ii.
An electrolyte (typically an aqueous phase) is in contact with the steel
Cracking of materials by the mechanisms addressed in this appendix requires that an
electrolyte or aqueous phase that may enter a nominally dry system.
Applicable conditions for SSC and HIC susceptibility for carbon or low alloy steel can be
referred to sections 17.4.3 and 17.4.4 of this appendix.
Applicable conditions for SSC, SCC and GHSC susceptibility for CRA can be referred to section
17.5.4 of this appendix.
The approach to materials selection and testing has been standardised and is described in
the applicable sections of this appendix.
17.4
CARBON AND LOW ALLOY STEELS
All carbon and low alloy steel piping operating in upstream exploration and production
environments (offshore/onshore) that are or maybe exposed to process streams where
potential cracking mechanisms caused by sour process environment are considered a risk shall
be designed and fabricated in accordance with the additional requirements of this appendix.
There are several types of material damages that can occur as a result of aqueous hydrogen
charging in sour process environments. These include sulphide stress cracking (SSC) of hard
weldments and microstructures, hydrogen blistering, hydrogen induced cracking (HIC) and
stress-oriented hydrogen induced cracking (SOHIC).
SSC is the occurrence of brittle crack propagation under the combined action of stress and
absorbed atomic hydrogen. Hydrogen blistering, HIC and SOHIC are lamellar cracking
phenomena, often connected or (in the case of HIC and SOHIC) propagating in a stepwise
manner. Hydrogen blistering, HIC and SOHIC are most commonly associated with plate or strip
product forms and are much less common in seamless pipe or wrought products (although
HIC has been experienced in seamless products which have a poor microstructure due to
incorrect chemistry or heat treatment).
17.4.1 Material Requirements
All materials shall be in accordance with the chemistry, mechanical properties and heat
treatment requirements of NACE MR 0175/ISO 15156-2 and as specified by this appendix.
All materials shall be supplied in the normalised condition as a minimum requirement.
Normalising shall be carried out as a separate heat treatment.
The material hardness requirement shall be at 248 HV10 maximum.
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i.
Plates
Heat treatments other than normalising such as quench and tempering (Q+T) or
thermal/mechanical controlled process (TMCP), used to improve microstructure
homogeneity and enhance HIC resistance may be applied only with the approval
of the Owner.
ii.
Chemical Composition
Chemical composition (product analysis) shall meet the requirements of Table 17.2, unless
the standard material specification is more restrictive.
Single Elements
Carbon (C)
Manganese (Mn)
Phosphorous (P)
Sulphur (S)
Silicon (Si)
Nickel (Ni)
Copper (Cu)
Chromium (Cr)
Molybdenum (Mo)
Vanadium (V)
Niobium (Nb)
Titanium (Ti)
Boron (B)
Multiple Elements
Cr + Mo
Ni + Cu + Cr + Mo
Carbon Equivalent (CE)
Notes 1 and 2
Maximum %
0.20
1.30
0.01
0.003
0.40
0.40
0.40
0.30
0.12
0.02
0.02
0.02
0.001
0.30
0.80
0.43
t  50 mm (2 in)
0.45
50 mm (2 in) < t  200 mm (4 in)
t > 200 mm (4 in)
0.48
NOTES:
1. Carbon Equivalent (CE) shall be calculated by the following formula:
2. The micro-alloying elements boron (B), titanium (Ti), niobium (Nb) and
vanadium (V) shall not be intentionally added to the steel unless the TA has
given prior approval. Chemical analysis results and carbon equivalent shall be
reported in a material test report (MTR).
3. Refer to sections 17.4.3 and 17.4.4 for SSC and HIC requirements respectively.
Table 17.2: Material Chemistry Requirements (Note 3)
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iii.
Mechanical Properties
All plates shall have actual yield strength of less than 450 MPa (65 ksi). If the actual
yield strength is greater than 450 MPa (65 ksi), the materials shall undergo SSC
testing in addition to HIC testing.
iv.
Examination
Ultrasonic testing shall be performed on all carbon steel plate materials regardless
of the thickness according to ASTM A578, supplementary requirements S2.2,
maximum defect area 100mm2 or EN10160 grade S2E2 to avoid the presence of
delaminations that may initiate HIC. Scanning shall be continuous over 100 % of
the plate surface.
v.
Forgings
Forgings shall be in accordance with ASME SA-105N, ASME SA-266, ASME SA-350LF2 or ASME SA-765, with the following restrictions:
a) Carbon
: 0.25 % maximum
b) CE
: 0.43 maximum
c) Sulphur content
: 0.025% maximum
d) Hardness value
: 200HV10 maximum and shall be maintained as base
metal hardness value during welding procedure qualification and the
production welds
vi.
Seamless Pipes and Fittings
Seamless pipes shall be in accordance with ASME SA-106 or ASME SA-333 and
ASME SA-234/ASME SA-420 for fittings, with the following restrictions:
a) Carbon
: 0.23 % maximum
b) CE
: 0.43 maximum
c) Sulphur content
: 0.01% maximum
vii.
Welded Pipes and Fittings
Generally, only seamless pipes and fittings should be used for pressure vessel
nozzles. Base materials shall be in accordance with the above specifications.
Where this is impractical, welded pipes and fittings may be used and shall be
manufactured from plate complying with section 17.4.1 (i) of this appendix. Such
fittings shall be welded by means of welding procedures qualified in accordance
with section 17.4.2 of this appendix and shall be HIC tested.
viii.
Wrought Fittings for Seamless and Welded Type
Hardness value for wrought fittings shall be less than 210HV10 and shall be
maintained as a base metal hardness value during production welds.
17.4.2 Welding and Hardness Requirements
i.
Welding Procedure Qualification
Welding procedure qualification for sour service material during manufacturing
and fabrication shall include hardness and HIC testing requirement. HIC test
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results from the same HIC compliant base material and electrode can be used to
qualify other WPS with the same base material specification and electrode of
the same brand and specification. A separate HIC test is required to qualify WPS
with PWHT from the same base material and electrode.
The level of sulphur in the welding consumables should be controlled to less
than 0.02%.
The welding consumables shall not contain more than 1.00% nickel. The welding
consumables containing more than 1.00% nickel are acceptable after successful
weld SSC qualification testing in accordance with NACE MR 0175/ISO 15156-2
Annex B.
In addition to the standard mechanical tests, each WPQT shall include a macrosection and hardness traverses in accordance with EN 1043-1. No part of the
weld, HAZ or base metal shall exceed 248 HV 10. WPQT hardness testing shall be
performed by the Vickers method.
ii.
Production Welds
The following shall be implemented for piping fabrication:
a) Transverse weld hardness testing of production welds shall be carried out
at the root and cap weld using a portable Vickers hardness tester in
accordance with ASTM E 110 or by another method capable of detecting
the hardness in a reliable and reputable manner if approved by Owner.
b) Hardness tests shall be made on properly prepared ground surfaces.
c) On heat-treated piping, hardness testing shall be carried out after PWHT.
d) A minimum one set of hardness measurements shall be carried out for
each Welding Procedure Specification (WPS) applied during weld
production for piping and subsequently 5% of the total joints for each
WPS.
e) For each set of hardness measurements required, the average of three
measurements on the weld and on each HAZ shall be reported.
f) No part of the weld and HAZ shall exceed 248 HV 10.
When one set of the average hardness measurements fails to meet the required
acceptance criteria for piping, two additional weldments shall be prepared for
retesting. If one or both of the retest weldments fail, then this shall be cause for
rejection of the weldment.
iii.
Weld Joint Requirements
Flux Core Arc Welding (FCAW) shall not be used for pressure boundary or welds
attaching parts to the pressure boundary.
Filler material with yield strength greater than 450 MPa (65 ksi) shall undergo
SSC testing in addition to HIC testing. All arc strikes and areas where temporary
attachments have been welded shall be ground smooth. Appropriate NDT
method (MT and/or PT) shall be conducted after ground smooth
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Same NDT method shall be conducted prior to and after PWHT.
iv.
Weld Heat Treatment
PWHT shall be conducted as specified in ASME section B31.3/ASME B31.8 for
piping. The final hardness value of the weldment, HAZ and base metal shall be at
248 HV10 maximum.
If the nominal thickness is less than specified in ASME section B31.3/ASME B31.8
for piping but the hardness value is more than 248HV10, PWHT shall be
conducted to reduce the final hardness below 248 HV10. As an alternative, the
weldment for the piping maybe cut out and re-welded. The maximum hardness
for the new weld shall be below 248HV10
17.4.3 Requirements for SSC Testing
The materials shall comply with SSC-resistant carbon and low alloy steel materials
requirements as per NACE MR 0175/ISO 15156-2 Annex A and as specified in this appendix.
Materials which do not meet any of the requirements stated above or with yield strength
above 65 ksi shall undergo SSC Test. The material hardness shall be at maximum of 248
HV10.
i.
Test Procedures and Reporting
Test procedures and reporting shall be performed in accordance with NACE
TM0177 Solution A.
ii.
Acceptance Criteria
Acceptance criteria shall be in accordance with NACE MR0175/ISO 15156-2 Annex
B.
17.4.4 Requirements for HIC Testing
The risk of HIC to carbon steel or low alloy steel materials shall be considered if the partial
pressure of wet H2S > 3.0 mbar (0.05 psi) as specified in section 17.3.0.
HIC testing is not required in the event of partial pressure of wet H2S < 3.0 mbar (0.05 psi).
However, HIC testing requirement shall be considered under the following conditions:
i.
Inadequate and/or contradicting H2S data
ii.
High potential souring of the reservoir
iii.
Future tie-ins with high H2S fields
iv.
Longer design/operating life of the facilities e.g. > 25 years
HIC test shall be performed on flat rolled carbon steel products and welded pipe with the
maximum sulphur content 0.003%, regardless of the material thickness. If the sulphur content
is greater than 0.003%, the materials shall be rejected.
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Seamless pipes or products e.g. nozzles and forged carbon steel materials are not required to
be HIC tested but shall comply with maximum sulphur requirement specified in Table 17.3.
These materials shall be HIC tested if the maximum sulphur level is exceeded.
Steel product
Seamless
%wt
0.01
Forging
0.025
Table 17.3: Maximum Acceptable Level of Sulphur in Steels
Casting products are not required to be HIC tested unless joining and repair by welding is to
be utilized.
i.
Test Procedures and Reporting
Testing and reporting shall be in accordance with PTS 15.23.01: Hydrogen induced
cracking sensitivity test (Amendments/supplements to NACE TM0284).
The equipment or material supplier shall be responsible for ensuring their
equipment or material complies with the HIC testing requirements. HIC testing by
the original material manufacturer is acceptable provided traceability of the
materials to the final product is established.
Material inspection certificates shall be in accordance with ISO 10474 Type 3.1C
or EN 10204 Type 3.2. The equipment or material supplier shall be responsible to
appoint the approved independent 3rd party inspector by the Owner.
ii.
Acceptance Criteria
Acceptance criteria shall be in accordance with PTS 15.23.01, as stated in Table
17.4 below:
%(maximum)
Average per specimen
CLR
15
CTR
5
CSR
2
Table 17.4: Acceptance Criteria for HIC Testing
17.5
CORROSION RESISTANT ALLOYS (CRA) MATERIALS
All materials shall be in accordance with NACE MR 0175/ISO 15156-3 and as specified by this
appendix in sections 17.5.1 and 17.5.2 for Austenitic and Duplex Stainless Steels respectively.
Other CRA materials shall be referred to NACE MR 0175/ISO 15156-3.
17.5.1 Austenitic Stainless Steels (Identified As Material Type and As Individual Alloys) Table A.2 of
Annex-A in NACE MR 0175/ISO 15156-3 shall be replaced with Table 17.6 as shown below. If
any of properties specified in Table 6 are exceeded, the Austenitic Stainless Steels shall be
tested for SSC, SCC and GHSC cracking resistance as indicated in section17. 5.4
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No
Materials
type/
Individual
alloy UNS
number
Tempera
ture
max
0
C (F)
93 (200)
1
2
S31603
(316L) (b)
S20910
(XM-19) (c)
All other
Austenitic
stainless
steel
3
Partial
Pressure
H2S,pH2S
Chloride
concentra
tion
max
kPa (psi)
max
mg/L
10.2 (1.5)
5 000
pH
Sulphur
Resistant?
(d)
≥ 5.0
No
120 (248)
0.8 (0.12)
60 000
See
remarks
No
149 (300)
155 (311)
10.2 (1.5)
1.5 (0.22)
1 000
38 000
≥ 4.0
≥ 3.8
No
No
66 (150)
100 (15)
See
remarks
See
remarks
No
60 (140)
1.5 (0.22)
60 000
See
remarks
No
See
remarks
See
remarks
50
See
remarks
No
from
materials
type
described
in A.2 of
NACE MR
0175/ISO
15156-3 (a)
Remarks
Any in-situ pH
occurring in
production
environment is
acceptable
Any
combinations of
chloride
concentration
and in situ pH
occurring in
production
environments are
acceptable.
Any in-situ pH
occurring in
production
environments is
acceptable
Cold working
(bending) of
instrument
tubing up to 9.5%
total deformation
is acceptable
even if the
maximum
hardness of 22
HRC is exceeded
These materials
have been used
without
restrictions on
temperature,
pH2S, or in situ
pH in production
environment. No
limits on
individual
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No
Materials
type/
Individual
alloy UNS
number
Tempera
ture
max
0
C (F)
Partial
Pressure
H2S,pH2S
Chloride
concentra
tion
max
kPa (psi)
max
mg/L
pH
Sulphur
Resistant?
(d)
Remarks
parameters are
set but some
combinations of
the values of
these parameters
might not be
acceptable.
NOTES:
A limit on the martensite content of these austenitic stainless steels should be considered. The stress
corrosion cracking resistance of all austenitic stainless steels of the material type described in A.2 can
be adversely affected by cold working.
(a) These materials shall:
 be in the solution-annealed and quenched, or annealed and thermally-stabilized heat-treatment
condition,
 be free of cold work intended to enhance their mechanical properties, and
 have a maximum hardness of 22 HRC.
 have a ferrite number in the range of 3FN to 8FN for the base material, HAZ and the weldment.
(b) UNS S31603 shall be in the solution-annealed and quenched condition when used in
environments outside the limits imposed for the material type (i.e. in the top two rows), but within
those given specifically for S31603. The following conditions shall apply:
 The material shall be free from cold work caused by shaping, forming, cold reducing, tension,
expansion, etc. after the final solution annealing and quenching treatment.

After the final solution annealing and quenching treatment, hardness and cold work incidental to
machining or straightening, shall not exceed the limits imposed by the appropriate product
specification.
(c) UNS S20910 is acceptable for environments inside the limits imposed for the material type and for
this alloy specifically, in the annealed or hot-rolled (hot/cold-worked) condition at a maximum
hardness of 35 HRC.
(d) All the above indicated Austenitic Stainless Steel shall not be used if the hydrocarbon has any
presence of elemental sulphur. If there is any presence of elemental sulphur, the material shall be
selected based on Annex F Table F-1 MR0175/ISO15156-3/Cir.2:2013(E)
Table 17.6: Environmental and Materials Limits for Austenitic Stainless Steels Used for Any
Equipment or Components
17.5.2 Duplex Stainless Steels (Identified As Material Type and As Individual Alloys)Table A.24 of
Annex-A in NACE MR 0175/ISO 15156-3 shall be replaced with Table 17.7 as shown below. If
any of properties specified in Table 17.7 is exceeded, the Duplex Stainless Steels shall be
tested for SSC, SCC and GHSC cracking resistance as indicated in section 17.5.4
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No
Materials
type/
Individual
alloy UNS
number
1
30 ≤ FPREN ≤
40,
Mo ≥ 1.5 %
2
40 < FPREN ≤
45
Temperature Partial
Pressure
H2S,pH2S
Chloride
pH
concentra
tion
max
0
C (F)
max
kPa (psi)
max
mg/L
200 (390)
1 (0.15)
150 000
200 (390)
2 (0.3)
150 000
200 (390)
8 (1.2)
30 000
See
remarks
See
remarks
See
remarks
Sulphur
Resistant
? (b)
Remarks
No
Any in situ pH
occurring in
production
environments
is acceptable
No
No
3
30 ≤ FPREN ≤
40,
Mo ≥ 1.5 %
See remarks
See
remarks
50
See
remarks
NDS(a)
4
40 < FPREN ≤
45
See remarks
See
remarks
50
See
remarks
NDS(a)
These
materials have
been used
without
restriction on
temperature,
pH2S or in situ
pH in
production
environment.
No limits on
individual
parameters
are set but
some
combinations
of the values
of these
parameters
might not be
acceptable
Wrought and cast duplex stainless steels shall:
 be solution-annealed and liquid-quenched,

have a ferrite content (volume fraction) of between 40-60% for base material and HAZ, and 3060% for weldment and

not have undergone ageing heat-treatments.
Hot isostatic pressure-produced (HIP) duplex stainless steel UNS S31803 (30 ≤ FPREN ≤ 40, Mo ≥ 1.5
%) shall have a maximum hardness of 25 HRC and shall:
 be solution-annealed and liquid-quenched,

have a ferrite content (volume fraction) of between 40-60% for base material and HAZ, and 3060% for weldment and

not have undergone ageing heat-treatments
NOTES:
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Higher values of FPREN provide higher corrosion resistance; however, they also lead to increased risk
of sigma- and alpha- prime phase formation, in the materials' ferrite phase, during manufacture,
depending on product thickness and achievable quench rate. The ranges of FPREN quoted are typical
of those found to minimize the problem of sigma- and alpha-prime phase formation. For FPREN
calculation can be referred to Section 6.3 of NACE MR 0175/ISO 15156-3. The reference FPREN value
also given in Annex D of NACE MR 0175/ISO 15156-3
(a) No data submitted to ascertain whether these materials are acceptable for service in the
presence of elemental sulphur in the process environment. Refer to note (b)
(b) All the above indicated Duplex Stainless Steel shall not be used if the hydrocarbon has any
presence of elemental sulphur. If there is any presence of elemental sulphur, the material shall be
selected based on Annex F Table F-1 MR0175/ISO15156-3/Cir.2:2013(E)
Table 17.7: Environmental and Materials Limits for Duplex Stainless Steels Used for Any Equipment
or Component
17.5.3 Welding and Hardness Requirements
The requirements for the cracking-resistance properties of weldment of austenitic stainless
steels and duplex stainless steels (and their materials groups) shall be in accordance with
NACE MR 0175/ISO 15156-3 section A.2.3 and A.7.3 respectively.
However, the ferrite content (volume fraction) of duplex stainless steel shall be in between
40-60% for base material and HAZ, and 30-60% for weldment.
The maximum hardness for weldment and HAZ for Austenitic Stainless Steel and Duplex
Stainless Steel are 22HRC and 28 HRC respectively.
17.5.4 Requirements for SSC, SCC and GHSC Test
The materials shall comply with SSC/SCC/GHSC-resistant CRA materials requirements as per
Annex A in NACE MR 0175/ISO 15156-3 and as specified by this appendix.
Materials which do not meet any of the requirements stated above shall undergo SSC, SCC
and GHSC Test.
i.
Test Procedures and Reporting
Test procedures and reporting shall be performed in accordance with NACE
TM0177 Solution A.
ii.
Acceptance Criteria
Acceptance criteria shall be in accordance with Annex B of NACE MR0175/ISO
15156-3
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17.6
CARBON OR LOW ALLOY STEEL MATERIALS CLAD WITH CRAs
Piping may be constructed as Carbon Steel Clad with CRAs depends upon an analysis of the
corrosivity of the internal and external environment, material properties and economic
factors.
CRA cladding will reduce the amount of hydrogen produced due to corrosion (possibly to zero
- no corrosion process on the CRA) and diffusion of hydrogen through the CRA will be several
orders of magnitude slower than through carbon steel.
Therefore the risk of SSC and HIC on the carbon steel behind the cladding is considered
negligible and no HIC and SSC testing are required for fully cladded piping.
In case where the risk of erosion is expected throughout the service life to damage the CRA
cladded layer, the base carbon and low alloy steel materials shall comply with the requirement
as per section 17.4 of this appendix.
For internal cladding performed through weld overlay, carbon or low alloy steel base materials
shall follow the SSC and HIC requirements as per sections 17.4.3 and 17.4.4 of this appendix.
Sheet lining is not acceptable for sour service application for piping and its components.
The additional following requirement shall be followed for both partially and fully carbon or
low alloy steel CRA clad pressure vessel:
i.
NDT inspection shall be applied with 100% coverage on the CRA surface of
cladded carbon or low alloy steel material e.g. UT and DPI to ensure there will be
no defects that exposed to the surface of carbon or low alloy steel e.g. pinhole
etc.
ii.
The materials for cladding shall comply with SSC/SCC/GHSC-resistant CRA
material requirements as per Annex A in NACE MR 0175/ISO 15156-3 and as
specified by this appendix in section 17.5.
17.6.1 Welding and Hardness Requirements
The requirement of welding and hardness for carbon steel or low alloy steel clad with CRA
shall be similar with requirement as specified in section 17.5.3 depend upon the respective
consumables used.
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APPENDIX 18
18.1
: WET H2S SERVICE REQUIREMENT FOR DOWNSTREAM PIPING
SCOPE
This specification establishes the minimum requirements for wet H2S service requirements
for downstream piping.
18.2
SPECIFIC ABBREVIATIONS
The same abbreviations in Appendix 17 applies for this Appendix.
18.3
DEFINITION AND SUSCEPTIBILITY TO SOUR SERVICE
"Wet H2S" (for downstream) or “Sour Service” (for upstream) are the terms used for Oil and
Gas process environments containing water and H2S (including other corrosives or
contaminants). The Specific Definition of Terms are listed in Table 18.1 below.
No.
1.
Terms
H2S content of
water
Definition
The sum of the dissolved (molecular) H2S, bisulphide ion (HS-1),
and sulphide ion (S-2) concentrations in the water phase,
resulting from the presence of H2S in the process system.
2.
Cyanide content
of water
The concentration of ‘free’ cyanide [CNFree], expressed in
ppmw, in the sour water resulting from the presence of HCN
and CN- in the process stream.
3.
The carbonate
ion (CO3-2)
concentration
This is the actual carbonate ion concentration used to
determine the susceptibility to carbonate cracking.
4.
Sulphide Stress
Cracking (SSC)
Carbon and low alloy steel can be susceptible to SSC when
exposed to wet H2S. SSC is a form of delayed fracture
consecutive to absorption of hydrogen specifically in the
presence of H2S. Only short duration of exposure (a matter of
hours) can be sufficient to lead to SSC.
5.
Hydrogen
Induced
Cracking (HIC)
HIC is also related to hydrogen embrittlement in presence of
H2S and is identified as internal cracking caused by gaseous
hydrogen recombination inside steels. Step Wise Cracking
(SWC) is a form of embrittlement related to HIC. SWC is a
cracking mechanism that connects hydrogen-induced cracks
on adjacent planes in steel. These phenomena are slower than
SSC and can take several months or few years to occur.
The susceptibility to HIC/SWC depends on the amount of
metallic impurities in the steel (mainly sulphur) and on the
manufacturing route that induce particular microstructure and
inclusion morphology.
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No.
Terms
Definition
HIC concerns only flat-rolled and long products such as plates,
strips etc. HIC risk shall be considered for continuous wet H2S
service conditions.
6.
Stress Oriented
Hydrogen
Induced
Cracking
(SOHIC)
SOHIC is SSC caused by combination of external stress and the
local strain around HIC. SOHIC is related to SSC and HIC/SWC.
It has been observed in parent metal and in the HAZ of welds.
Carbonate
Stress Corrosion
Cracking
(Carbonate SCC)
Carbon and low alloy steel in wet H2S environment containing
also carbonate can be susceptible to Carbonate SCC. The risk
of cracking mostly depends on the carbonate concentration,
the pH, the NH3 content and the ratio NH3/H2S.
7.
SOHIC risk is only considered for carbon and low alloy steel
piping operated continuously in wet H2S service.
Table 18.1: Specific Definition of Terms
18.3.1 Susceptibility to cracking and Wet H2S severity categories
Environment severity e.g water, H2S, CNFree, CO3-2, material properties e.g chemistry,
mechanical properties, thermal history and susceptibility of materials to each potential
damage mechanism shall be considered in the selection of materials, testing and
requirements for PWHT of downstream piping.
i.
Process environment considerations
Process environment in normal operating condition and short-term upsets e.g
start-up, shutdown, process upsets, shall(PSR) be considered if the damage
mechanism is anticipated. For normal operating condition, Table 18.2 provides
the Wet H2S severity category based on pH, cyanide content and suplhide content
of water.
Where more than one active mechanism is anticipated, the materials and PWHT
requirements may have to be combined.
Owner shall approve the Wet H2S severity category for each piping.
ii.
Wet H2S severity categories
The wet HsS severity category shall be assessed in accordance with Table 18.2.
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Sulphide content of water
[mg/kg (ppmw)]
Cyanide content
[mg/kg (ppmw)]
(Note 1)
<1
<4
NA
Neg
HIC
HIC
HIC
≥4
NA
Neg
Neg
HIC
HIC
7.6 to 7.9
>50
Neg
HIC
HIC
SOHIC
>20
Neg
HIC
Table 18.2: Wet H2S Severity Categories
SOHIC
SOHIC
pH of water
1 to 49
50 to 1000
> 1000
WET H2S SEVERITY CATEGORY
(Note 2)
>7.6
Note 1: The level of cyanide has no significance at pH 7.5 and below
Note 2: pH values are from NACE MR 0103
Note 3: Wet H2S is considered when H2S partial pressure exceeds 0.0003 MPa a (0.05 psia) with presence of
water.
Supplementary requirements to Table 18.2 are as follows:
Wet H2S service – HIC is applicable to:
1 Piping in contact with gas phase, if the partial pressure of H2S is higher than 0.3 kPa
and cyanide content is lower than 20 ppm.
Wet H2S service – SOHIC is applicable to:
1 Piping in contact with gas phase, if the partial pressure of H2S is higher than 0.3 kPa
and cyanide content is higher than 20 ppm.
Carbonate Stress Corrosion Cracking – CSCC is applicable to:
1 Wet H2S service and a pH of 7.6 or greater and carbonate concentration of 100
ppmwt or greater in water.
2 Wet H2S service and a pH of 8.4 or greater and carbonate concentration of 10
ppmwt or greater in water.
Table 18.3 Supplementary requirements to Table 18.2
Cracking of materials by the mechanisms addressed in this appendix requires that an
electrolyte or aqueous phase that may enter a nominally dry system.
The approach to materials selection and testing has been standardised and is described in
the applicable sections of this appendix.
18.4
CARBON AND LOW ALLOY STEELS
All carbon and low alloy steel piping operating in downstream that are or maybe exposed to
process streams where potential cracking mechanisms caused by wet H2S environment are
considered a risk shall be designed and fabricated in accordance with the additional
requirements of this appendix.
18.4.1 Material Requirements
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All materials exposed to wet H2S service including pressure retaining base materials shall (PSR)
be supplied with an inspection certificate in accordance with EN 10204 Type 3.2.
The requirements for chemical analysis shall apply to heat and product analysis. For welded
components, chemical analysis shall include the elements used for the determination of CE.
All carbon steel components shall comply with ISO 15156/NACE MR 0103.
All materials shall be supplied in the normalised condition as a minimum requirement.
Normalising shall be carried out as a separate heat treatment.
The material hardness requirement shall be at 248 HV10 maximum.
i.
Plates
Plates shall conform to ASME II SA 516 or ASTM A 516 (as applicable) with
supplementary requirement S1 (Vacuum Treatment) and S3 (Simulated Post
Weld Heat Treatment of Mechanical Test Coupons).
Non pressure retaining attachments, both internally and externally, are
exempted from this PTS with the exception of materials as detailed in 18.4.1
which has undergone successful Wet Fluorescent Magnet Particle Testing.
Plates produced from coils are not permitted.
All carbon steel plate materials shall be fully killed and supplied in the
normalized condition. The acceptability of hot-finished material shall be subject
to the approval of the Owner.
Other heat treatment conditions such as Q&T or TMCP shall be subjected to
Owner agreement.
Plate material shall be mechanically tested in the simulated PWHT condition (to
anticipate the minimum heat treatment cycles foreseen during fabrication of the
piping).
a) Chemical Composition
Chemical composition (product analysis) shall meet the requirements of
Table 17.2, unless the standard material specification is more restrictive.
Single Elements
Maximum %
Carbon (C)
0.20
Manganese (Mn)
1.30
Phosphorous (P)
0.01
Sulphur (S)
0.002
Silicon (Si)
0.40
Nickel (Ni)
Copper (Cu)
0.40
0.40
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Single Elements
Maximum %
Chromium (Cr)
0.30
Molybdenum (Mo)
0.12
Vanadium (V) (note 2)
0.02
Niobium (Nb) (note 2)
0.02
Titanium (Ti) (note 2)
0.02
Boron (B) (note 2)
0.0005
Oxygen
0.0025
Multiple Elements
Cr + Mo
0.30
Ni + Cu + Cr + Mo
Carbon Equivalent (CE)
Notes 1 and 2
0.80
t  50 mm (2 in)
0.43
50 mm (2 in) < t  200 mm (4 in)
0.45
t > 200 mm (4 in)
0.48
NOTES:
1. Carbon Equivalent (CE) shall be calculated by the following
formula:
2. The micro-alloying elements boron (B), titanium (Ti), niobium (Nb)
and vanadium (V) shall not be intentionally added to the steel unless
the Owner has given prior approval. Chemical analysis results and
carbon equivalent shall be reported in a material test report (MTR).
3. Refer to sections 17.4.3 and 17.4.4 for SSC and HIC requirements
respectively.
Table 18.4: Material Chemistry Requirements (Note 3)
b) Mechanical Properties
All plates shall have actual yield strength of less than 450 MPa (65 ksi). If
the actual yield strength is greater than 450 MPa (65 ksi), the materials
shall undergo SSC testing in addition to HIC testing.
c) Manufacturing of Steel Plate
The steel shall be produced by electric arc furnace or in the basic oxygen
furnace process. The steel shall be vacuum degassed and produced to a
fine grain practice, with low sulphur and phosphorus process. Grain size
shall be 7 or finer as defined by ASTM E 112.
Calcium treatment shall be applied for inclusion shape control, except
that it need not be applied to plate with very low sulphur levels (below
0.002%). The calcium content should not exceed 3 times the sulphur
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content. Alternative methods of inclusion shape control shall be subject
to the acceptance of Owner.
The manufacturing/rolling process shall be such that a homogeneous
microstructure is obtained, i.e. the structure shall be free of any
significant ferrite/pearlite banding and any centre line segregation.
The Manufacturer shall submit the following information in the proposal:

Steel making route, deoxidisation and desulphurisation practice,
inclusion shape control method, use of vacuum degassing.
 Casting route, ingot or continuous casting, segregation control
procedures, rolling reduction.
Material test certificate shall include the provisions for simulated PWHT
to anticipate maximum heat treatment cycle foreseen during
fabrication of the piping in accordance with the supplementary
requirements S3 of ASTM A 20. As a minimum, material certificate shall
include but not limited to:
 Chemistry
 Mechanical properties after simulated PWHT
 HIC testing results (when required)
 UT results
 Impact tests results (when required to satisfy MDMT
requirements)
 Heat treatment reports
 Hardness test results and location shall be recorded in Certified
Material Test Records
d) Examination
Ultrasonic testing shall be performed on all carbon steel plate materials
regardless of the thickness according to ASTM A578, supplementary
requirements S2.2, maximum defect area 100mm2 or EN10160 grade
S2E2 to avoid the presence of delaminations that may initiate HIC.
Scanning shall be continuous over 100 % of the plate surface.
Acceptance criteria Level C shall apply.
ii.
Forgings
Forgings shall be in accordance with ASME SA-105N, ASME SA-266, ASME SA-350LF2 or ASME SA-765, with the following restrictions:
Element
Maximum %
Carbon
0.25
Manganese
1.35
Phosphorus
0.015
Sulphur
0.010
CE (formula in Table 18.4)
0.43
Table 18.5 Chemical Analysis Requirement for Forgings
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For any reduction of 0.01 below the specified Mn % content, an increase of 0.01
Sulphur and Phosphorus above the specified maximum values shall be permitted
up to respectively 0.025 for Phosphorus and 0.015 for Sulphur.
No HIC Testing is required on Forgings.
Hardness value shall be 200 HV10 maximum and shall be maintained as base
metal hardness value during welding procedure qualification and the production
welds.
iii.
Seamless Pipes and Fittings
Chemical analysis on heat shall be in accordance with following restrictions:
Element
Maximum %
Carbon
0.23
Manganese
1.20
Silicon
0.30
Sulphur
0.010
Phosphorus
0.020
CE (formula in F.4.1.1.1)
0.43
Table 18.6: Chemical Analysis Requirement for Seamless Pipe and Fittings
e) Welded Pipes and Fittings
Welded pipe and welded pipe fittings manufactured from plates shall
meet all the requirements of 18.4.1 i. including HIC testing. Welding
procedure qualification and associated hardness restrictions shall be in
accordance with 18.4.2 of this specification.
After rolling and welding, pipes shall be subjected to PWHT in accordance
with 18.4.1 vii at the pipe mill (Refer NACE SP 0472).
Longitudinal welds shall be examined on their full length by UT
and/or RT.
CE calculated using the formula specified in 18.4.1 ii shall be 0.43%
Maximum.
f)
Wrought Fittings for Seamless and Welded Type
Hardness value for wrought fittings shall be less than 210 HV10 and shall
be maintained as a base metal hardness value during production welds.
g) Forming
Carbon steel shall be thermally stress-relieved (either PWHT as per
18.4.2.5 or Normalized) following any cold deforming by rolling,
cold forging, or another manufacturing process that results in a
permanent outer fibre deformation greater than 5%.
The use of pipe and weld caps for shells and heads is not allowed.
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18.4.2 Welding and Hardness Requirements
i.
Welding Procedure Qualification
Welding procedure qualification for wet H2S service material during
manufacturing and fabrication shall include hardness and HIC testing
requirement. HIC test results from the same HIC compliant base material and
electrode can be used to qualify other WPS with the same base material
specification and electrode of the same brand and specification. A separate HIC
test is required to qualify WPS with PWHT from the same base material and
electrode.
The level of sulphur in the welding consumables should be controlled to less than
0.02%.
Welding parameters for production welding shall be within the following ranges
of the PQR:
 Amps
-5% to +15%
 Volts
-5% to +15%
 Travel Speed -15% to +5%.
Minimum / maximum interpass temperatures shall be restricted to the values
shown in the supporting WPQR and the maximum interpass temperature shall
be 200°C.
ii.
Hardness Test on Transverse Section
In addition to the standard mechanical tests, each WPQT/WPQR shall include a
macro-section and hardness traverses in accordance with EN 1043-1. No part of
the weld, HAZ or base metal shall exceed 248 HV10. WPQT hardness testing shall
be performed by the Vickers method.
The series of readings shall include unaffected base material (BM), Heat Affected
Zone (HAZ), Weld Metal (WM). Typically HAZ is taken from Fusion Line (FL) +2mm
and from FL +5mm.
Photomacrographs showing the indent locations shall be submitted with the PQR.
The maximum hardness shall not exceed 210 HV10 in any area of BM, WM and
HAZ.
WPQR shall also include surface Brinell hardness test on WM, and BM as per the
same test method that will be used during production as per 18.4.1.4. The
maximum value shall not exceed 200HB.
Test coupons for hardness testing shall be subject to the minimum heat treatment
cycle anticipated during fabrication.
iii.
Production Welds
The following shall be implemented for piping fabrication:
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a) Transverse weld hardness testing of production welds shall be carried out
at the root and cap weld using a portable Vickers hardness tester in
accordance with ASTM E 110 or by another method capable of detecting
the hardness in a reliable and reputable manner if approved by Owner.
b) Hardness tests shall be made on properly prepared ground surfaces.
c) Each hardness test shall be carried out on 100% of groove/butt welds and
branch connection welds.
d) When access is available, tests shall be performed on the process
contacted side of the weld (I.D).
e) Hardness test shall include WM, BM and HAZ
f) The hardness shall be determined as an average of three (3) values
equally spaced around weld diameter.
g) On heat-treated piping, hardness testing shall be carried out after PWHT.
h) Hardness results shall not exceed: 200HB for P-No.1 Material in “Wet H2S
service”
i) The hardness report shall indicate actual hardness reading for the
test method used, type of hardness tester, personnel conducting
hardness tests, type of material, and calibration.
j) When one set of the average hardness measurements fails to meet the
required acceptance criteria for piping, two additional weldments shall be
prepared for retesting. If one or both of the retest weldments fail, then
this shall be cause for rejection of the weldment.
iv.
Weld Joint Requirements
Flux Core Arc Welding (FCAW) shall not be used for pressure boundary or welds
attaching parts to the pressure boundary.
Filler material with yield strength greater than 450 MPa (65 ksi) shall undergo SSC
testing in addition to HIC testing. All arc strikes and areas where temporary
attachments have been welded shall be ground smooth. Appropriate NDT method
(MT and/or PT) shall be conducted after ground smooth
Same NDT method shall be conducted prior to and after PWHT on all arc strikes
and locations where temporary attachments have been removed and ground
smooth; all accessible inside surfaces of pressure retaining welds and internal
accessible attachment welds. No linear indications shall be acceptable.
Nickel content of welding consumables shall not exceed 1%.
Weld metal analysis shall be within ASME IX A-Numbers 1.
v.
Post Weld Heat Treatment
PWHT is mandatory irrespective of thickness when classified as wet H2S service
category.
PWHT shall be conducted as specified in ASME section B31.3/ASME B31.8 for
piping. The final hardness value of the weldment, HAZ and base metal shall be at
248 HV10 maximum.
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If the nominal thickness is less than specified in ASME section B31.3/ASME B31.8
for piping but the hardness value is more than 248HV10, PWHT shall be conducted
to reduce the final hardness below 248 HV10. As an alternative, the weldment for
the piping maybe cut out and re-welded. The maximum hardness for the new
weld shall be below 248HV10.
When Carbonate SCC is expected in the service, the minimum heat treatment
temperature shall be 650°C with a hold time of one hour per 25 mm of thickness,
with a minimum of one hour.
18.4.3 Requirements for SSC and SOHIC Testing
If there is no evidence on the suitability of wet H2S service for the raw materials or
manufacturing procedure provided by the plate manufacturer or Contractor, SSC tests shall
be conducted as part of the manufacturing procedure qualification.
Three specimens shall be taken transverse to the weld.
All SSC test specimens which meet the acceptance criteria of 18.4.3.1 shall be evaluated for
SOHIC. However, Contractor shall seek Owner advice on the necessity of SOHIC test.
Test procedures and reporting shall be performed according to NACE TM0177 Solution A.
Materials which do not meet any of the requirements stated above or with yield strength
above 65 ksi shall undergo SSC Test. The material hardness shall be at maximum of 248 HV10.
i.
Acceptance Criteria
The SSC acceptance criteria shall be to ISO 15156-2 Annex B, clause B.4.2.3.
Minimum acceptance criteria for SOHIC test shall be agreed with Owner.
18.4.4 Requirements for HIC Testing
HIC test shall be performed on flat rolled carbon steel products and/or welded pipe.
i.
Test Procedures and Reporting
Testing and reporting shall be in accordance with PTS 15.23.01: Hydrogen induced
cracking sensitivity test (Amendments/supplements to NACE TM0284).
The vendor/supplier shall be responsible for ensuring their piping or material
complies with the HIC testing requirements. HIC testing by the original material
manufacturer is acceptable provided traceability of the materials to the final
product is established.
Material inspection certificates shall be in accordance with ISO 10474 Type 3.1C
or EN 10204 Type 3.2. The piping or material supplier shall be responsible to
appoint the approved independent 3rd party inspector by the Owner.
147.158.181.104 mshafiq.yusof@mmhe.com.my 12/28/2022 12:02:38 GMT
PTS 12.30.02
PIPING GENERAL REQUIREMENTS
December 2017
Page 168 of 168
ii.
Acceptance Criteria
Acceptance criteria shall be in compliance with PTS 15.23.01, as stated in Table
18.7 below:
%(maximum)
Average per specimen
CLR
15
CTR
5
CSR
2
Table 18.7: Acceptance Criteria for HIC Testing
18.5
OTHER METALLIC MATERIALS
Metallic materials are classified in several material groups in NACE MR0103 Table 1.
All alloys highlighted below may be suitable in “Wet H2S service” provided they comply with
the following requirements.
18.5.1 Alloy Steel, Cast Iron and Ductile Iron
This covers sections 2.1 and 2.2 of NACE MR0103, with the exception of Carbon Steel.
i.
Material Requirements
For downstream piping, NACE MR0103 requirements shall apply. Alternatively,
PTS 15.01.05, PART III Amendments and supplements to ISO 15156-2 may be
applied at the discretion of the Owner.
18.5.2 Alloy Steel Non Ferrous Material
This covers sections 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.1, 3.2, 3.3 and 3.4 of NACE MR0103.
i.
Material Requirements
For downstream piping, NACE MR0103 requirements shall apply. Alternatively,
PTS 15.01.05, PART IV Amendments and supplements to ISO 15156-3 may be
applied at the discretion of the Owner.
a) Titanium alloy
For temperatures greater than 80°C, Titanium alloys shall not be allowed in
“Wet H2S service”.
Titanium alloys shall be galvanically insulated from materials which can
create an electrical couple with titanium.
b) Aluminum alloys
In process streams outside the pH range of 4.0 to 8.5, Aluminum alloys shall
not be allowed.
c) Copper alloys
The Owner shall review the condition for the use of copper alloys in process
streams containing free NH3, amines, sulphides.
147.158.181.104 mshafiq.yusof@mmhe.com.my 12/28/2022 12:02:38 GMT