RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
RAS MARKAZ CRUDE OIL PARK
GAS TESTING PROCEDURE
B1
21 Apr 21
33
Issue for Approval
Huang Xing
Jude O
Xing Hang
A1
02 Sep 20
32
Issue for Review / Comments
Huang X
Jude O.
Xing Hang
REV
DATE
PAGES
DESCRIPTION
PP /CHK /APP
Page 1 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Table of Contents
1
GENERAL ..................................................................................................................................................... 4
2
PURPOSE..................................................................................................................................................... 5
3
SCOPE .......................................................................................................................................................... 5
4
CHANGES TO THE DOCUMENT ............................................................................................................... 5
5
ALARP ......................................................................................................................................................... 6
6
DEFINITIONS AND ABBREVIATIONS ..................................................................................................... 6
7
REFERENCE DOCUMENTS ........................................................................................................................ 7
8
ROLES AND RESPONSIBILITIES ............................................................................................................... 8
9
GAS TESTING ............................................................................................................................................11
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
SCOPE .......................................................................................................................................................... 11
POTENTIAL HAZARDS .................................................................................................................................... 11
GAS TEST REQUIREMENTS.............................................................................................................................. 12
TESTING INSTRUMENTS.................................................................................................................................. 14
COMBUSTIBLE GASES..................................................................................................................................... 15
TOXIC AND SUFFOCATING GASES ................................................................................................................... 17
OXYGEN DEFICIENCY ..................................................................................................................................... 18
GAS TESTER .................................................................................................................................................. 18
PRE-USER CHECKS ........................................................................................................................................ 18
GAS TESTING PROCESS .................................................................................................................................. 20
APPENDIX 1 – ATMOSPHERIC TESTING .......................................................................................................22
APPENDIX 2 – OXYGEN CONTENT TESTING ...............................................................................................23
APPENDIX 3 – FLAMMABLE GAS TESTING ..................................................................................................25
APPENDIX 4 - TOXIC GAS TESTING ..............................................................................................................27
APPENDIX 5 – HYDROCARBON VAPOUR NARCOTIC EFFECT ..................................................................29
APPENDIX 6 – DENSITY OF DIFFERENT GASES ...........................................................................................30
APPENDIX 7 – GAS TESTING CHECKLIST .....................................................................................................31
APPENDIX 8 – EXPLOSIVE RANGE AND GAS BEHAVIOUR ........................................................................32
A1
APPENDIX 9-CONFINEDSPACE CERTIFICATE………………………………………………………………………34
Page 2 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
REVISION CONTROL SHEET
REV. NO.
A1
DATE
02 Sep 20
PAGE NO.
All Pages
DESCRIPTION OF CHANGES
First Issue
B1
20 Apr 21
All Pages
Second Issue Revised as per Company Comments
This page records the revision status of this document
NOTES:
Revisions after first issue are denoted as follows:
a)
By a vertical line in the right-hand margin against the revised text and,
b)
By a triangle symbol for graphics, the revision number being denoted within the symbol.
Revision symbols are positioned adjacent to the revision.
Page 3 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
1
Rev. B1
Doc. Class 1 /Cat: 2
GENERAL
Oman Tank Terminal Company (OTTCO) plans to build a new grassroots Crude Oil Storage Terminal at
Ras Markaz, on the eastern Arabian Sea coast of the Sultanate of Oman. The proposed coastal site is
located approximately 70 km south of DUQM. The site is approximately 130m above the sea level and
terminates at a cliff edge with little or no coastal beach area at sea level. The size of the area available for
terminal development is roughly 13 km2.
The terminal is to be designed to provide a total gross storage capacity of up to 200 Million Barrels of
crude oil (MMbbl). The Project will involve the design, construction and operation of offshore tanker
loading / offloading facilities, onshore storage facilities and associated infrastructure, pipelines and roads.
The facility is to be designed to handle the loading and offloading of crude oil from and to the following
vessels:

Suezmax;

Very Large Crude Oil Carriers (VLCC);

Ultra Large Crude Oil Carriers (ULCC).
The principal modes of terminal operation will be:

Tanker unloading into the Storage Facilities
Page 4 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040

Tanker loading from the Storage Facilities

Inter-tank transfers within the Storage Facilities

Crude oil import by pipeline from Nahada

Crude oil export by pipeline to Duqm Refinery

Tank Crude Oil Blending
Doc. Class 1 /Cat: 2
PURPOSE
2
A1
3
Rev. B1
The purpose of this procedure is to present the significance of the high level requirements for gas testing
and define the key hazards and methods of testing. Gas testing is mandatory prior to work especially
hot work, during purging operations, to investigate gas alarms, during entry into confined spaces, etc.
being undertaken in a process or hydrocarbon area that carries a risk to personnel or equipment from
exposure to explosive, flammable, toxic or life threatening vapours. Gas testing shall also be required in
any other area where the above risks are considered to exist which are covered by EPC Contractor Permit
to Work system.
SCOPE
This procedure applies to all personnel during pre-commissioning, commissioning, start-up, servicing
and performing maintenance on machine, equipment and systems associated with the process line in
which an unexpected ignition could occur if there is any heat source electrostatic discharge. This
procedure specifies minimum requirements for the prevention of ignition from gases or hydrocarbon
cloud.
It is applicable for protecting all employees in EPC Contractor, Subcontractors and Vendors undertaking
the projects from the hazards of gases, fumes, vapors and where Hydrocarbons, oil and gas are produced
or treated and where presence of Toxic and combustible gases and Oxygen deficiency / enrichment
possibility has been proven by the safe method of gas testing.
4
CHANGES TO THE DOCUMENT
Responsibility for the upkeep of the Document shall be with EPC Contractor HSE Manager, the Custodian.
Changes to this document shall only be authorised and approved by the Owner.
Users of the Document who identify inaccuracy or ambiguity can notify the Custodian or his/her delegate
and request changes be initiated. The Requests shall be forwarded to the Custodian. The Document
Custodian should ensure review and re-verification of this procedure every 2 years.
Page 5 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
5
Rev. B1
Doc. Class 1 /Cat: 2
ALARP
ALARP is the acronym for ‘As Low As Reasonably Practicable’ which simplified means, ‘reducing the risk
to a level at which the cost and effort (time and trouble) of further risk reduction are grossly
disproportionate to the risk reduction achieved’. Full Compliance to EPC Contractor Standards and
Procedures is a key element in achieving ALARP.
6
DEFINITIONS AND ABBREVIATIONS
AGT
:
Authorized Gas Tester
ALARP
:
As Low As Reasonably Practicable
Authorized
Employee
:
Is a person who uses the energy control procedure.
Affected Employee
Is a person who works in an area in which the energy control
procedure has been implemented.
Company
:
Oman Tank Terminal Company L.L.C. (OTTCO)
Contract
:
The EPC Contract between Company and EPC Contractor
Consultant (PMC)
:
Worley Parsons Engineering Pty Ltd (WP)
Dangerous goods
:
Articles, chemicals, materials, or substances that are capable of posing
a significant risk to health, safety, or property when transported by air
EPC Contractor
:
China Petroleum Pipeline Engineering Co., Ltd. (CPP)
Energize
:
Connected to an energy source or containing residual or stored energy
Energy Isolating
Device
:
Is a mechanical device that physically prevents the transmission or
Energy Source
:
Entry Permit
:
IDHL
:
IPMT
:
Company Project Management Team comprising OTTCO and
Consultant personnel.
Energy Source
:
Any source of electrical, mechanical, hydraulic, pneumatic, chemical,
thermal, or other energy
HRA
:
release of energy.
An energy source is any electrical, mechanical, hydraulic,
pneumatic, gravitational, chemical, nuclear, thermal, or other energy
source that could cause injury
A written document provided by the worker that specifies the
conditions of entry into a hazardous confined space
Immediately Dangerous to Life or Health
Health Risk Assessment
Page 6 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
A1
7
Rev. B1
Doc. Class 1 /Cat: 2
JHA
:
Job Hazard Analysis
LEL
:
Lower Explosive Limit
MSDS
:
Material Safety Data Sheet
NORM
:
Naturally Occurring Radioactive Material
O&M
:
Operation and Maintenance
Oxygen Deficiency
:
An atmosphere containing oxygen at a concentration of less than
19.5% by volume as measured by an oxygen measuring device.
PPE
:
Personal Protective Equipment
PPM
:
Parts Per Million
PTW
:
Permit To Work
SCBA
:
Self-Contained Breathing Apparatus
SHOC
:
Safe Handling of Chemicals
STEL
:
Short Term Exposure Limit
Sub-contractor
:
Means any person or persons, firms, companies to whom any part of
the work has been subcontracted (directly or indirectly) by EPC
Contractor and the legal successors in title to each of these parties
Shall
:
Indicates Mandatory requirement
Should
:
Indicates that the requirement is strongly recommended to be
adhered to
TLV
:
Threshold Limit Value
TRIC
:
Toolbox Risk Identification Card
Vendor
:
Means a supplier of Goods and/or Equipment for the Facility and/or
the Works including related documentation and services, where
necessary, in connection with the installation, testing, commissioning
and start up support of any such Goods or Equipment.
UEL
:
Upper Explosive Limit
REFERENCE DOCUMENTS
RD 114/2001
:
Law for the Conservation of the Environment and Prevention of
Pollution
RD 35/2003
:
Oman Labour Law
MD 286-2008
:
The regulation of Occupational Safety and Health for the
Establishments
Page 7 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
5440-8710-SP-000-0002
:
HSE Instruction to Contractor
9686-6160-PR-000-0001
:
Project HSSE Plan
9686-6160-PR-000-0002
:
Construction Environmental Management Plan
9686-6160-PR-000-0003
:
Health Management Plan
9686-6160-PR-000-0004
:
Security Management Plan
9686-6160-PR-000-0005
:
Emergency Preparedness and Response Plan
9686-8130-PR-000-0001
:
Commissioning Procedure
9686-6160-PR-000-0005
:
Commissioning HSE Plan
9686-6160-PR-000-0006
:
Incident Reporting & Investigation Procedure
9686-6160-PR-000-0008
:
Permit To Work Procedure
9686-6160-PR-000-0008
:
Risk Assessment and Management Procedure
9686-6160-PR-000-0017
:
Environmental Monitoring Plan
9686-6160-PR-000-0012
:
Audit and Inspection Procedure
9686-6160-PR-000-0013
:
Fire Prevention Procedure
OHSAS 18001/45001
:
Occupational
Requirements
OHSAS 18002
:
Guidelines for the implementation of OHSAS 18001
ILO Convention
:
Convention concerning Safety and Health in Construction
Health
&
Safety
Management
System,
Environmental Management System, Requirements
ISO 14001
ILO Convention
:
Convention concerning Safety and Health in Construction
ROLES AND RESPONSIBILITIES
8
A1
All affected personnel must be familiar with this procedure and Trained . If they do not
understand something within the procedure they shall ask their line supervisor or
Operations Team /Operations head to explain it. It is the line Supervisor’s Responsibility to
ensure that all his subordinates have been adequately instructed and understood this
procedure.
Role
The Deputy Project
Manager
Responsibility

Ensure that the work is carried out as per this present document,
where necessary.

Ensure that a system is in place to train and to evaluate the
competency of the designated gas testers.
Page 8 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
HSE Manager
A1
Commissioning
Manager
Permit Applicant
Rev. B1
Doc. Class 1 /Cat: 2

Provide sufficient signs, barriers and flashing lights as
appropriate to the area covered.

Provide instruction with regard to the hazards and arrangements
in place.

To provide sufficient numbers of compatible and approved gas
detection equipment on site.

Planning the work, as far as practicable, to include contingency
plans and arrangements.

Adequate calibration and test equipment, with spare parts that
can be fitted on site.

Ensure sufficient numbers of Rescue equipment as required by
the numbers of persons who may be exposed.

Monitor the safety of all working practices.

Custody of portable gas detection equipment and the training of
the site designated gas testers.

Ensure adequate and appropriate emergency plans and
equipment are in place should an incident occur.

Ensure all necessary tests are carried out as required by the Work
site condition and as stated by the permit to work system upon
completion of a specific risk assessment.

Ensure supervision and Subcontractor management are familiar
with this procedure and that all persons concerned are trained as
well.

Ensuring all the necessary gas checks have been identified and
carried out prior to the issue of relevant Work Permits.

Monitor site conditions and ensuring that persons who may be
affected by this procedure are aware of the hazards and
precautions to be taken.

Arrange for the necessary training of personnel for testing,
calibration and maintenance of records.

Update this procedure as necessary.

Ensure that routine calibration checks of all portable gas
detectors are carried out in accordance with the manufacturers’
instructions.

Ensuring that all persons working are aware of, and comply with
the relevant points from this Safety Procedure.

Communicate all activities with the HSE department and
participate in SIMOPS activities.

Define the gas testing requirements for the work

Prepare the Job Safety Plan and indicate the frequency of gas
testing
Page 9 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040

Area Authority
A1
Issuing Authority
A1
Authorised Gas
Tester
Rev. B1
Doc. Class 1 /Cat: 2
Ensure a gas free test certificate / Confined Space Entry Certificate
where scheduled tests readings are logged is attached to the
work related PTW & JSA

Complete the appropriate section for gas testing on the PTW

Indicate the special gas detection equipment is required e.g.
hydrocarbons in inert

Tick the gases to be tested for on PTW.

Verify that a gas free test certificate / Confined Space Entry
Certificate where scheduled tests readings are logged is attached
to the work related PTW & JSA.

Indicate how often the test shall be repeated on PTW.

State if continuous monitoring for gas is required during the work.

Gives possible advise for safety assurance

Agree requirements of gas testing with the Permit Applicant

Agree the Job Safety Analysis.

Ensure an authorised gas tester handles the activity

Ensure all technicians under his supervision read and understand
the procedures

Comply with EPC Contractor Permit to Work System regarding
gas testing requirements and frequencies

Performs all Gas testing activities

Complete a gas free test certificate / Confined Space Entry
Certificate attached to the work related PTW & JSA - where
scheduled tests readings are logged.

Carryout ‘ad-hoc’ gas testing when required

Enter gas test results and frequency of further tests on PTW and
Confined Space Entry Certificate / Additional Gas Test sheet (if
applicable),
A1
NOTE: Authorised Gas tester to agree test results with area
authority and enter into PTW.
Permit Holder
HSSE Supervisor

Include gas testing requirements in the TRIC

Agree gas test results

Ensure compliance to gas testing requirements is adhered to

Ensure correct type of gas detector is used for the gas testing
activity

Monitor the safety of all working practices.

Ensuring that all necessary gas tests are carried out by AGT as
required by the Work Permit System
Page 10 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Maintenance/
Operations Staff
9
9.1
Rev. B1
Doc. Class 1 /Cat: 2

Ensure that work area is free of any dangerous gas.

Ensure details of the area gas testing records are kept

Ensure all PPE needed to carry out the job is used

Ensure the emergency preparedness plan is in place and everyone
knows what to do

Comply with this procedure

Ensure the procedures are read and understood

Report every anomaly to the HSE department
GAS TESTING
Scope
The scope of this procedure shall cover;
-
the hazards which gas testing shall address;
-
the requirements for gas testing;
-
typical testing instruments used;
-
the gas tester and;
-
pre-user checks
The procedure shall make reference where appropriate to material located in other documents and
provide links to those documents where necessary.
9.2
Potential Hazards
Generally the potential hazards addressed by gas testing are;
-
Oxygen enriched atmosphere
-
Oxygen depleted atmosphere
-
Flammable or explosive atmosphere
-
Toxic atmosphere
-
Hydrocarbon enriched atmosphere (narcotic effect)
Each of the above shall be addressed with a more detailed description in the Appendix.
9.2.1
Oxygen Enriched Atmosphere
Atmospheres containing more than 21.5 % vol. oxygen shall be treated as oxygen enriched. Generally
oxygen enrichment does not occur often as the source of the extra oxygen shall have to be introduced.
Oxygen enriched atmospheres when mixed with hydrocarbons can result in explosive mixtures quicker
than would be the case with normal air (20.8%).
Page 11 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
9.2.2
Rev. B1
Doc. Class 1 /Cat: 2
Oxygen Depleted Atmosphere
Atmospheres containing less that 20% vol. oxygen shall be treated as oxygen depleted. Such
atmospheres can occur when gas freeing of purging has been carried out to remove hydrocarbons /
toxics or air. The oxygen in the atmosphere shall have been normally replaced / diluted with an inert gas
i.e. nitrogen.
9.2.3
Flammable Atmosphere
Flammable or explosive atmospheres are those that contain mixtures when exposed to an ignition source
will or may ignite and burn. Such atmospheres can be created when opening pipework or equipment
that contains or has contained hydrocarbons.
9.2.4
Toxic Atmosphere
Toxic atmospheres are those that contain concentrations of vapours that shall cause injury or death to
humans. Such atmospheres may have sufficient oxygen to support life and insufficient flammable
concentrations to cause explosions or fire, but may contain sufficient concentrations of the toxic to harm
personnel. An example would be H2S or mercury.
9.2.5
Hydrocarbon Enriched Atmosphere
Hydrocarbon enriched atmospheres are those where the concentrations of hydrocarbon vapours are
sufficient to induce a narcotic effect on personnel inside the atmosphere.
9.3
A1
Gas Test Requirements
The Confined space certificate shall be referenced to determine the frequency of gas testing and the
specific work it is required for and it will be confirmed and validated by Area Authority.
In general gas testing is required for the following types of work;
 Breaking containment
 Hot work in a process or hydrocarbon area
 Gas freeing and purging
 Confined space entry / work within a confined space
 Checking for suspected gas leaks
 Providing clearance for work activities
A1
 Use of diesel engines in a process / hydrocarbon area( Petrol Vehicles are not allowed in a process
facility/Hydrocarbon area)
 Vehicle entry to a process / hydrocarbon area
Page 12 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
 Possible areas of frequent hydrocarbon drift
9.3.1
Breaking Containment
Gas testing shall be required when containment is broken on any system containing hydrocarbon or
toxic liquids / solids / vapours. Appropriate PPE and safety equipment i.e. SCBA, masks, face visors etc,
shall be worn as necessary.
The type of gas tested for shall be indicated on the PTW by the Area Authority in addition to the
frequency of testing. Types of gas can include one or all of the following;
 Hydrocarbons
 H2S
 Mercury
 NORM
9.3.2
Hot Work in a Process or Hydrocarbon Area
Hot work carried out in an area where hydrocarbons are present or can be present must be preceded by
a gas test of the work site and adjacent areas to address the risk of fire and explosion caused by
concentrations within the Lower Explosive Limits.
The gas test shall be primarily for hydrocarbons and carried out in accordance with the specification of
the Permit to Work.
9.3.3
Gas Freeing or Purging
Gas freeing of pipework and equipment shall be carried out prior to work being undertaken on
hydrocarbon or toxic system. The normal medium for gas freeing is an inert, nitrogen or water.
During gas freeing processes using nitrogen the gas testing shall be to detect hydrocarbons in an inert
atmosphere and requires the appropriate testing equipment to be used.
9.3.4
Confined Space Entry/Work within a confined space
Spaces or vessels requiring entry by personnel to inspect or carryout work shall require to be tested prior
to and during the work.
Confined space gas testing shall be to determine whether the atmosphere within the space can safely
support life. Tests shall be for oxygen content and hydrocarbons / toxics.
9.3.5
Checking for Suspected Gas Leak
Small gas leaks in and around pipework and equipment may be detected using portable gas testing
equipment.
Page 13 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
9.3.6
Rev. B1
Doc. Class 1 /Cat: 2
Providing Clearance for Work Activities
Work activities in hazardous area shall require that the atmosphere at the work site and in the
surrounding areas is safe before permission is given to carry-out the work activity.
9.3.7
Use of Diesel Engines in a Process / Hydrocarbon Area
The use of internal combustion engines (diesel driven) within a process or hydrocarbon area shall be
subject to authorization and require gas testing in accordance with EPC Contractor permit to work
system
Diesel driven plant i.e. mobile cranes, air compressors etc, shall be subject to continuous gas monitoring
while in use. The units shall also be subject to a gas test prior to starting.
The gas test shall primarily be to check for hydrocarbons.
9.3.8
Vehicle Entry to a Process / Hydrocarbon Area
Vehicles shall only be allowed into a process area if covered by a PTW. A PTW is not required for a
hazardous area but gas testing is mandatory for both.
Vehicles shall be subject to continuous gas monitoring while inside the area.
The gas test shall be to check for an explosive or flammable atmosphere
9.4
Testing Instruments
Gas testing shall only be carried out by authorized ‘gas testing’ personnel who have completed the 3rd
Party training. The details of these personnel shall be registered with EPC Contractor.
A1
Testing must be carried out using approved instruments. The following types will be in use by EPC
Contractor:
 Multigas monitors (indication usually in %LEL or %Vol or ppm dependant on the gas being
monitored)
 Explosimeters (indication usually in %LEL)
 Detector tubes (indication usually in ppm or volume)
NOTE: When testing for mercury, NORM or hydrocarbons in an inert atmosphere specialist meters are
required and the user shall be trained in its use.
Page 14 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
9.4.1
Rev. B1
Doc. Class 1 /Cat: 2
Multi Gas Monitors
Multigas monitors are capable of measuring a number of gases simultaneously. The gases monitored
and displayed can include Flammable, Oxygen, Carbon Monoxide, Hydrogen Sulphide, Sulphur Dioxide,
Chlorine, Nitrogen Dioxide, Ammonia, and Carbon Dioxide. The results are displayed continuously.
The multigas meter is provided with a sample pump allowing for deep penetration testing of confined
spaces and well cellars from a safe location.
Audible and visual alarm is provided making the monitors suitable for deployment in the confined space
or as perimeter guard for protection and warning.
9.4.2
A1
9.4.3
Explosimeter Monitors
Explosimeter are provided to measure only ‘flammable’ gases. The monitor will provide a measurement
of the immediate area from which the sample is taken, which can be remote if sample lines and probes
are used. The reading is displayed on a meter by needle deflection. The sensitivity of the instrument is
set by the control ‘knob’. The instrument shall only be used by personnel who have undertaken the
appropriate 3rd Party Training.
Detector Tubes
Detector tubes are single ‘spot’ check devices for detection of gases in the direct vicinity of where the
sample is taken. Different detector tubes are provided for different gases, the selection of the detection
tube being dependent on the gas being detected.
A ‘fixed volume1’ sample is drawn through the detector tube by a hand pump. The detector tubes are
calibrated and the change in colour observed will indicate the concentration of the gas present.
9.5
Combustible Gases
9.5.1
Maximum Permissible Concentration
The explosive, or flammability limits of gases and vapors, are normally expressed as a volume percentage
range between Lower Explosive Limits (LEL) and Upper Explosive Limits (UEL). These levels vary for
different compounds and it is the Lower Explosive Limit (LEL) that is used as a basis for the combustible
gas test. The table below lists the LEL and UEL of some relevant gases:
GAS
LEL %
UEL %
Methane
5.30
13.30
Ethane
3.00
15.50
Butane
1.86
8.41
Page 15 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Pentane
1.30
7.80
Propane
2.10
9.30
Hydrogen
4.00
74.20
hydrogen sulfide
4.30
46.00
Acetylene
2.50
82.00
Ammonia
15.00
28.00
Doc. Class 1 /Cat: 2
For example, in an atmosphere containing Methane, a reading of 10 % LEL on the explosimeter dial
indicates that the actual concentration in the air is 10 % of 5.3 = 0.53 % by volume. (See Figure 1 of this
procedure.) Note that an explosimeter needs sufficient range of oxygen to give a true reading (more
than 15% Volume).Unless otherwise stated in manufactures’ manual; Explosimeter to measure the % of
LEL do not work correctly when the atmosphere contains less than 15% Oxygen.
Before opening a vessel or pipe work to the atmosphere always ensure it is free from gases and
hydrocarbon content. In case of O2 deficiency (less than 15%) such as gas freeing activities, gas testing
shall be performed by Infra Red (IR) combustible gas detectors. Before gas testing of any pipeline, vessel
or equipment , it is required to know about the fluid of that pipeline or equipment then to know about
density of the specified gas which needs to be checked by gas testing.
9.5.2
Combustible Gas Detectors
Combustible gas tests must be carried out using only gas detectors suitably calibrated for use with
hydrogen and/or hydrocarbon gas mixtures. Meter readings are given as a percentage of the LEL of the
combustible gas and it is the result which must be specified in the appropriate space of the Work Permit.
Sludge or scale, within a vessel, gives off vapor when disturbed and/or heated, this fact must be borne
in mind when testing for gas in a confined space to determine the suitability for entry. Before and after
each series of tests, or up to a maximum of two-hours continuous use, the meter must be checked for
minimum response, following the procedure in the instruction manual. Information and results from
detectors must be reported to the Safety supervisor /Safety Engineer.
Oils heavier than kerosene do not give off sufficient vapor at ambient temperature to be detected. Work
places must, therefore always be visually inspected for the presence of such oils, and if present, they
must be removed, or blanketed, to the satisfaction of Production/Site Superintendent and the Safety
Authority. Information and results from detectors and any gas chromatography analysis must be
reported to the person in charge of the installation and the Safety Authority for assessment.
Water, or liquid hydrocarbons, must not be allowed to enter the instrument. When testing sumps or
equipment where liquid could be present, a liquid trap must be fitted to the sample line.
Warning: The calibration gas used should be as closed as possible from the potentially explosive
atmosphere monitored. Particularly the reading of the explosimeter when sampling condensates vapors
Page 16 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
might be over optimistic if methane is used as calibration gas (which is generally the case in gas
processing plant).
9.5.3
Continuous Monitors
There are various instruments available for the continuous monitoring of combustible gas atmosphere.
Some instruments are designed as free-standing, self-powered units fitted with a portable diffusion head
and flammable gas and vapor detectors. They are used with an alarm system.
Gas concentrations up to 100 % LEL are indicated on a meter and the alarm is a penetrating audio signal,
coupled with a flashing lamp. The level at which the alarm operates can be pre-set by internal
adjustment. The monitor can be used for spot sampling with the addition of an aspirator. By the addition
of an aspirator the monitor can be used for spot sampling.
Warning: Combustible gas detectors are designated to detect gas in AIR. It is not possible for the
instrument to give an accurate LEL reading in a steam, inert or oxygen deficient / enriched atmosphere.
Special equipment ("Tank safe" monitor) or chemical detector tubes shall be used in such cases.
9.6
Toxic and Suffocating Gases
9.6.1
Maximum Permissible Concentration
The toxic gases most likely to be encountered are Hydrogen Sulfide (H2S) and Carbon Monoxide (CO).
The maximum concentrations of these toxic gases for entry are as follows:
MAXIMUM CONCENTRATIONS OF TOXIC GAS (PPM) FOR ENTRY
Gas
Entry
without
Breathing Apparatus
Hydrogen Sulfide
(H2S)
< 1 ppm
1 to 20 ppm
> 20 ppm
< 1 ppm
1 to 250 ppm
> 250 ppm
Carbon Monoxide
(CO)
Entry With Suitable
Breathing Apparatus
No Entry Purge and
Retest
There are two methods used for the detection of toxic gases:
 Portable Detectors, used for continuous monitoring.
 Detector Tubes, used to measure the concentration in a spot test.
H2S is heavier than air so may concentrate in lower areas; it is resolvable in water or sludge, so it is essential
to empty the vessels and containers before any entry to, or hot work activities
Page 17 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
9.6.2
Rev. B1
Doc. Class 1 /Cat: 2
Portable Detectors (Continuous Monitoring)
Some types of portable detectors allow the monitoring of hydrogen, carbon monoxide or sulfur dioxide
content in the range 0 - 200 ppm by means of interchangeable sensor heads. The instrument gives
audible and visual alarms, which are adjustable throughout the measuring range.
There are two levels of alarm that produce different tones and visual LED indication for the Long Term
Exposure Limit (LTEL) and Short Term Exposure Limit (STEL) values of the toxic gas being measured. The
concentration is displayed on a meter in ppm.
9.7
Oxygen Deficiency
Before entering a vessel or enclosed space, tests of the oxygen content of the atmosphere must be
made. Tests must also be carried out whenever there is any doubt as to purity of the air within a vessel.
Internal rusting of the metal in a closed empty tank, which has been unused for some time, may cause
oxygen deficiency. Oxygen deficiency tests are carried out by:
 Oxygen Monitors - continuous checking.
 Multi-gas Detectors - spot checks.
Clearance to enter a vessel or confined space without wearing breathing apparatus is only given when
the concentration of oxygen in the atmosphere is in an acceptable level. Acceptable level of an
atmospheric oxygen concentration is 20.9 percent. Although the OSHA recommended Oxygen level for
entry is between %20 to %23 but we must note that the reduction or enhancement of oxygen may be
reason for presence of toxic gas or other chemical reaction.
9.8
Gas Tester
An Authorised Gas Tester (AGT) is a person who has passed the 3rd Party Gas Testing Course and holds
a current Gas Testers Card, and has passed either a Permit to Work Signatories or Holders Course.
9.9
Pre-User Checks
Before using a portable gas detector (with exception of detector tubes) the following shall be observed:
 Ensure that the gas detector ‘test’ is in date. Do not use a gas detector that is ‘out of test’
 Check the gas detector for signs of damage. If damaged record and report the nature of the damage
and exchange the gas detector for one that is undamaged (if possible)
 Before using the gas detector ensure the ‘battery’ is fully charged
 After switching on purge the gas detector with uncontaminated air
 Allow the gas detector to complete the ‘start-up sequence’ (if applicable) before use
 If the gas detector uses a calibration gas check that the reading is correct to the calibration gas
Page 18 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
 Follow all manufacturers safety instructions for use
NOTE: If in doubt reference the Manufacturers O&M manual
In both cases, the Authorised Gas Tester must:
 Gas test at the frequency stated on the Permit or Confined Space Entry Certificate.
 Fill in the result of the gas test on the Gas Test Record and Sign it.
 When a test result indicates that it is NOT safe to work, the Authorised Gas Tester must:
 Tell the Permit Holder to stop any current work.
 Tell the Permit Holder and Area Authority that it is not safe to work, and why, so that the problem
can be dealt with.
Page 19 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
A1
9.10
Rev. B1
Doc. Class 1 /Cat: 2
Gas Testing Process
Permit Applicant
Area authority
Issuing Authority
Identifies the gas
Permit Holder
Inspect the location
testing requirements
for the work
Authorised Gas Tester
with PA and Informs the
Review And
AA in case of any
Agrees the
additional requirements
requirement
Enter the
requirements on the
Permit to work
Validate the PTW
Authorizes the
daily after inspecting
PTW
the work location,
monitor of gas testing
by AGT
Ensure the Permit
holder is informed of
gas testing
requirements
Conduct daily TBT
Enter the type of gases to be
and Ensure all the
tested and frequency of testing
workers are trained
on PTW (Commissioning&
and safe to work
Hydro carbon area)/CSC
certificate
PTWH
HOT Work
COLD Work
Carries out Initial gas
test each day in
accordance with
requirements using
correct device
Agree Gas test
results with AA and
AGT
Carries out Initial
gas test each day
and IA will monitor
the activity
Carries out
Subsequent gas test
in accordance with
requirements using
correct device
Maintain gas test Log
Page 20 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
The process, as described below, shall be typical of the normal gas testing carried out EPC Contractor in
accordance with the Permit to Work system.
1.
The Permit Applicant shall identify the gas testing requirements for the work to be
undertaken.
The gas testing requirements shall be entered on the PTW
2.
A1
The Area Authority shall review the gas testing requirements and agree or amend as
required.
For HOT Work permits a site visit is mandatory but for Cold work permits, it is
recommended.
Area Authority shall identify the gases to be tested for and the frequency of the gas
testing after the initial test.
The Area Authority shall authorise the PTW
3.
The Permit Applicant shall ensure that gas testing requirements are clearly explained
to the Permit Holder. These shall be included in the TRIC
4
The Area Authority /Issuing Authority shall enter the gases to be tested for and the
frequency of testing on the PTW before validation (see 2 above)
5.
Is the PTW a Hot work or a Cold work?
The class of the permit shall dictate who undertakes the initial gas test for the work
covered
For Hot Work permits(Commissioning & Hydro carbon area)
Authority/Issuing Authority will conduct the first gas test of each day.
the
Area
NOTE: This ruling can be changed to allow the Authorised Gas Tester (if not an Area
Authority) to conduct this test and requires the Area Authority authorisation and
approval
For Hot work and Cold work (Commissioning & Hydro carbon) permits an Authorised
Gas Tester can conduct all gas tests
6.
The Permit Holder shall witness the initial gas test and agree the result.
7.
The Area Authority / Authorised Gas tester shall conduct all subsequent gas tests
required by the PTW
8.
The Authorised Gas tester shall maintain the gas testing log
Page 21 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 1 – Atmospheric Testing
Atmospheric testing is required to evaluate the hazards of the permit space and for verification that
acceptable entry conditions for entry into that space exist. Similarly where ‘hot work’ is to be undertaken
which is adjacent to live plant Continuous gas testing shall be undertaken to evaluate the risk of
hydrocarbon or toxic gas (throughout the life of HOT work activity).
A1
Evaluation Testing
The atmosphere of the permit space should be analysed using test equipment for the specific gases
expected to be present to identify and evaluate any hazardous atmospheres that may exist or arise, so
that appropriate procedures can be developed to conduct the required work safely. Evaluation and
interpretation of the gas measurement data, and development of the procedure, should be done by, or
reviewed by technically qualified personnel based on a Risk Assessment.
Verification Testing
The atmosphere of a permit space which may contain a hazardous atmosphere shall be tested, using the
appropriate gas test equipment to evaluate conditions are safe, at the time of analysis, to commence
the required work. Results of testing (i.e., actual concentration, etc.) shall be recorded on the Permit to
Work (PTW). Measurement is by volume of the total atmosphere.
Duration of Testing
Measurement of values for each atmospheric parameter should be made for at least the minimum
response time of the test instrument specified by the manufacturer.
Testing Stratified Atmospheres
When monitoring for entries involving a descent into atmospheres that may be stratified, the
atmospheric envelope shall be tested a distance of approximately 4 feet (1.22 m) in the direction of travel
and to each side. If a sampling probe is used, the entrant's rate of progress should be slowed to
accommodate the sampling speed and detector response.
Order of Testing
A test for oxygen is performed first because most combustible gas meters are oxygen dependent and
will not provide reliable readings in an oxygen deficient atmosphere. Combustible gases are tested for
next because the threat of fire or explosion is both more immediate and more life threatening, in most
cases, than exposure to toxic gases and vapours. If tests for toxic gases and vapours are necessary, they
are performed last.
Page 22 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 2 – Oxygen Content Testing
Oxygen content shall be determined by gas testing when considering the entry of personnel into a
‘permit required confined space’. The tests shall generally include the following
Oxygen Deficiency
At atmospheric level the normal atmospheric concentration of oxygen is 20.8% vol. Atmospheres
containing less than 20% vol. oxygen are considered to be oxygen-deficient or hypoxic.
NOTE: The oxygen content of air reduces as altitude increases, therefore locations at more than 1000
metres above sea level appropriate corrections should be made and appropriate precautions taken.
Oxygen deficiency in an atmosphere can result in asphyxiation. A relatively small reduction in the oxygen
level can lead to impaired mental ability and can provoke a feeling of euphoria or well being leading to
an overoptimistic judgment of the situation. The effects generally occur without alerting the senses. Loss
of consciousness can occur without warning. This can happen even in circumstances where only a
person’s head is inside a confined space. Very low oxygen concentrations, below 10%, can lead to
unconsciousness and death. Inhaling an atmosphere with no oxygen results in instant death. There is no
panic or discomfort; death is swift and silent.
Oxygen deficiency can result from:
 Displacement of air from low points in a confined space by heavier gases such as hydrocarbons or
carbon dioxide;
 Purging of the confined space with an inert gas to remove flammable or toxic gases, fumes, vapours
or aerosols;
 Naturally occurring biological processes that consume oxygen, which can occur in sewers, storage
tanks, wells etc.;
 Leaving a vessel completely closed for some time, since the process of rust2 formation on the inside
surface consumes oxygen;
 Increased levels of carbon dioxide evolving from limestone chippings associated with drainage
operations;
 Burning and welding, which consume oxygen;
 Displacement of air during pipe freezing with liquid nitrogen;
 Gradual depletion of oxygen as workers breathe in confined spaces and where provision of
replacement air is inadequate.
Page 23 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Any reduction in the oxygen level from the atmospheric concentration shall be accounted for or investigated,
the risks assessed and appropriate measures taken. Entry into confined spaces containing 16 to 20% by
volume oxygen shall not be allowed unless a Risk Assessment has been completed and approval has been
obtained from the appropriate authority.
Note: Newly fabricated or shot blasted carbon steel vessels are especially vulnerable to rusting
CAUTION: This shall only be by exception, when the source of oxygen deficiency is understood and it is not
practical to ventilate the confined space to atmospheric oxygen level.
Atmospheres containing less than 16% vol. oxygen shall be treated in the same way as toxic atmospheres
that are Immediately Dangerous to Life and Health (IDLH).
Oxygen Enrichment
At atmospheric level the normal atmospheric concentration of oxygen is 20.8% vol. Atmospheres
containing more than 21.5 % vol. oxygen should be treated as oxygen enriched or hyperoxic.
Oxygen enrichment will significantly increase flammability of clothing, grease and other combustible
materials.
Oxygen enrichment can result from:
 Leaks from oxygen containing equipment such as gas cylinders, valves, hoses and welding torches;
 Inadvertent use of oxygen instead of air for ventilation or breathing air;
 Deliberate addition of oxygen to increase the level of an oxygen deficient atmosphere.
Any increase in the oxygen level above normal during confined space entry activities shall be
investigated, a Risk Assessment completed and appropriate measures taken.
The most common oxygen containing equipment is that used in gas cutting operations. Cylinders, gas
hoses, valves and welding torches shall be handled with care and should be daily inspected for damage.
Gas cylinders shall not be taken into confined spaces unless the risks have been assessed and appropriate
authorisation is obtained from the Responsible Supervisor. If allowed into the confined space all such
equipment shall be removed during breaks and at the end of the working day.
Page 24 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 3 – Flammable Gas Testing
Flammable gas testing shall be carried out to detect accumulations of flammable vapours, fumes or dust
which could ignite in the presence of a source of ignition.
Flammable vapours or fumes typically result from:
 Materials previously processed or stored in the vessel or tank;
 Electrostatic build up resulting from the interaction of incompatible fluids.
A1
 Sludge or other deposits disturbed during cleaning;
 Material left under scale, even after cleaning;
 Material leaking through the tank floors;
 Material leaking from behind vessel linings (lagging, refractory etc.) or from vessel fittings such as
tank floating roof pontoons and legs, instrument connections or pipes;
 Materials leaking from flanges or vents on process pipes running through the confined space, e.g.
process tubes in a furnace combustion chamber;
 Vapour entering the confined space from nearby process plant that has not been effectively isolated
or from nearby work that is not well controlled;
 Solvents brought into the space for cleaning, painting, dye penetration tests or in adhesives;
 Gases brought into the space / area for welding or gas cutting, including leakage from cylinders,
valves and hoses;
 Contaminated firewater / process water used to wash the confined space and introduced by hoses;
 Vapour or fumes that build up in sewers, manholes, contaminated ground or excavations.
A source of ignition can be any heat source having enough energy to ignite a flammable vapour air
mixture, or to raise the temperature above the auto-ignition temperature. Possible ignition sources
include:
 Open flames and sparks resulting from welding, gas cutting and grinding;
 Sparks or arcs produced by electrical equipment, lightning and electrostatic charges;
 Hot pipes or exhausts that can raise the flammable mixture above the auto-ignition temperature;
 Heat of friction during drilling, sawing or other cutting activities;
 Pyrophoric materials, e.g. iron sulphide in scale;
Page 25 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
 Thermite reactions from aluminium or other alloy tools striking against rusted iron or steel;
 Any highly reactive material capable of producing sufficient heat for combustion, for example:
-
Strong oxidising substances, such as hydrogen peroxide used in waste treatment facilities;
-
Chemicals that undergo self-accelerating exothermic reactions when a critical temperature is
reached, such as ethylene oxide.
The recommended approach to controlling flammable vapours in confined spaces or where ‘hot work’
is being undertaken is to eliminate all flammable materials from area before the work is undertaken. The
objective should be no detectable flammable vapour, i.e. an explosimeter reading less than 1% LEL.
WARNING: Confined space entry shall not be allowed into spaces where the flammable concentration is
greater than 10% LFL.
Page 26 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 4 - Toxic Gas Testing
Toxic gas testing shall be carried out to identify and detect toxic substances either in or adjacent to the
confined spaces or other places of work. Substances can be solids, liquids or gases. Toxic vapours can
cause injury, acute or long-latency illness, or death, depending on the characteristics of the substances,
the concentration and the duration of exposure. For example, prolonged exposure to benzene can cause
kidney damage or even leukaemia.
Toxic hazards in confined spaces can result from the same sources as the flammable hazards.
Common toxic substances in the oil and gas industry are:
 Acute toxic gases such as hydrogen sulphide, carbon monoxide, hydrogen fluoride, ammonia and
chlorine;
 Hazardous liquids such as benzene, polycyclic aromatics, lead/anti-knock compounds, hydrazine and
biocides;
 Narcotic gases and vapours such as butane, pentane, hexane, gasoline and gas condensate;
 Catalyst dusts, such as nickel, platinum, and molybdenum.
Toxicity data for specific substances, e.g. Material Safety Data Sheets (MSDS) or Safe Handling Of
Chemical Cards (SHOC), shall be required from the supplier of materials or from government authorities,
and shall be made available on site. If these are not available, then a competent industrial hygienist shall
assess the toxicity of the intermediates and products.
Crude oil and refinery process streams are mixtures of many hydrocarbons that individually have
significant toxic or narcotic effects. The Health Risk Assessment (HRA), as input to the Job Hazard Analysis
(JHA), shall assess the hazards of the mixture in the situation / areas where persons could be exposed.
Specifically, the HRA should make a recommendation on whether flammability measurements are
sufficient to detect harmful levels of the potentially toxic substance. Different criteria may be needed for:
 Confirming that the atmosphere in the confined space is safe for entry, for planned work, and
 Requiring persons to leave the space in case of an increased level during the work
Substances that are harmful by inhalation normally have an assigned Occupational Exposure Limit (OEL).
An Action Limit of 50% of the published OEL shall be applied as the trigger for implementing specific
measures for controlling exposure to the toxic substance during the confined space work, but the target
should be to reduce the airborne concentration to ALARP. OEL data may not be available for some toxic
dusts, sludge and other substances, in which case specialist occupational hygiene advice should be
sought.
Entry into confined spaces containing a concentration of toxic vapour, fume or dust between the OEL
and the IDLH value shall be allowed only by exception when and it is not practical to ventilate the
confined space or otherwise remove the hazard to reduce the toxic concentration. In this case it shall
Page 27 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
only be allowed when the source, nature and concentration of the toxic hazard is understood and
exposure is adequately controlled by other means.
Entry into confined spaces containing a concentration of toxic vapour, fume or dust above the IDLH
value shall not be allowed.
The most notable toxic gas to be encountered in EPC Contractor activities during commissioning and
startup is hydrogen sulphide (H2S). Allowable concentrations are related to the Threshold Limit Value
(TLV) which represents the concentration to which a worker may be exposed without suffering adverse
health effects.
For the H2S the TLV is 10 ppm, for an 8-hour period.
The short-term exposure level (STEL) for H2S is 15 ppm and is the concentration of H2S gas in air above
which protective equipment must be used.
Page 28 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 5 – Hydrocarbon Vapour Narcotic Effect
Testing for hydrocarbon vapour shall be carried out prior to / and during Confined Space Entry and at
any time that hydrocarbon vapours are suspected of being present in or around a space, vessel or tank
where personnel are working. Detection of hydrocarbon vapour is by the use of Drager Detection Tubes.
Page 29 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 6 – Density of Different Gases
GAS
Density (Air = 1)
Ammonia
Butane
Carbon Dioxide
Carbon Monoxide
Ethane
Ether (diethyl)
Ethylene
Ethylene Oxide
Formaldehyde
Hydrazine
Hydrogen
Hydrogen Cyanide (poison)
Hydrogen Sulphide (poison)
Methane
Mathanol
Methylamine
Nitric Oxide
Oxigen
Propane
0.6
2.1
1.5
0.97
1.05
2.5
0.97
1.5
1.07
1.1
0.07
0.93
1.18
0.54
1.1
1.08
1.04
1.1
1.55
Page 30 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 7 – Gas Testing Checklist
No.
Descriptio
n
1
Are personnel trained in the use of gas detector
equipment?
2
Are explosimeters only used when the level of
oxygen is sufficient i.e. > 15 %?
3
Yes
No
N/A
Comments
Are personnel aware of where to take sample
readings?
4
Are oxygen monitors with alarms worn by personnel
who enter enclosed spaces?
5
Is a gas test performed before any hot work?
6
Is there a permanent gas detector (with alarms set at
25% LEL) when any hot work is performed within a
vessel or an enclosed space?
7
Has the correct permit been issued?
8
Are oxygen levels checked sufficiently often for
work in an enclosed space?
9
Are personnel aware of the dangers of oxygen
enrichment?
10
Is there any possibility of the presence of H2S or
CO? If so, is it being tested for?
Page 31 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 8 – Explosive Range and Gas Behaviour
Gas Behaviour
Page 32 of 33
RAS MARKAZ CRUDE OIL PARK PROJECT (PHASE1)
GAS TESTING PROCEDURE
Doc No: 9686-6160-PR-000-0040
Rev. B1
Doc. Class 1 /Cat: 2
Appendix 9 – Confined space certificate
A1
Certificate No.
Confined Space Certificate
Work Permit No.
1. Details of Confined Space
Site / Location:
Equipment / Space to be Entered
Sub -Contractor:
Reason for Confined Space Entry: …………..............................................................................................................................................
……………………………………………………………………………………………………………………………………………………………………………………………………………
2. Worksite Preparation and Control Measures
(Items to be checked by Area Authority/Issuing Authority before Confined space entry can proceed and confirmed by signature in box 4&5)
Control Measures
Equipment/Vessel to be removed from service and isolated from all source of
dangerous liquid, gases.
Equipment / Vessel to be isolated from all source of energy
Conduct Gas Testing for the confined space atmosphere
Provide adequate access / Escape routes are provided
Provide adequate ventilation
Provide safe temporary lighting
Specific HSE Requirement
A rescue plan to be formulated and briefed to work
team
Safety harness and lifeline to be provided
Provide warning sign for CSE
Breathing Apparatus
Air Moving equipment installed & Operational
Lifelines & resuscitation equipment available
Standby personnel Name: …………………………………………………………………….
Equipment Surrounding area checked and safe from hazards
raising from other work/operations
Isolation Certificates are attached
Electrical Certificate No.
Mechanical Certificate No.
3. Gas Testing
GAS
Oxygen
Hydrocarbon
LIMIT
RESULTS
20 – 21% Vol.
0% LEL for Hot work, 4% LEL for Cold
Work without BA, 10 LEL for Cold work
with BA
%
%
GAS
H2S
Carbon Monoxide
LIMIT
RESULTS
10PPM
50PPM
PPM
PPM
Others
AGT Name: …………………………………………… Sign: …………………………… Auth. No. .………………….. Date: ……………………… Time: ……………………
Gas Test to be repeated at the intervals of ……….Hrs
/ Continuous Gas monitoring Required during the Execution of work Yes
No
Breathing Apparatus
need to be worn
4. Authorization to Enter Confined Space by Area Authority (AA)
I certify that the above results indicate that the Confined space covered by this certificate is safer to enter ,Gas Test to be repeated at the intervals specified as above
5. Issuing Authority (IA)
6. Permit Holder
7. Worksite Endorsement by Issuing Authority (IA) – Required every shift / Work Period
Date
Initial
Date
Initial
(To be signed by the off going permit holder
whenever work is suspended)
Issuing Authority (IA)
Permit Holder
Issuing Authority (IA)
Permit Holder
Issuing Authority
Permit Holder
Issuing Authority
Permit Holder
Issuing Authority
Permit Holder
Issuing Authority
Permit Holder
Issuing Authority
Permit Holder
(IA)
(IA)
(IA)
(IA)
(IA)
Certificate Closure
8. Closed and Permit Returned
Permit holder Name: ………………………………………………………………
Signature: ……………………………………………………………………………….
Date: ………………………………………………………………………………………
Area Authority (AA) Name: ……………………………………………………
Signature: ……………………………………………………………………………….
Date: ………………………………………………………………………………………
Page 33 of 33