Pipeline Repair Manual
DOCUMENT REVIEW
REFERENCE DOCUMENT:
PIPELINE REPAIR PROCEDURE MANUAL
COMMENTS:
Edits requested: The following items printed in bold letters are changes requested.
Title Page
PIPELINE REPAIR PROCEDURE MANUAL:
I.
Table of Contents (Page 1)
VII
Heat Treatment of Piping
VIII
Electrode Handling
IX
Removal of Detrimental Magnetic Fields at Pipeline Tie-ins
Index of Appendices (Page 2)
NOTE:
All Appendixes should be regrouped; i.e. all welding procedures together etc.
A-2
Hydrostatic Testing Procedure
E-1
List of Hot Tapping and Stopple Plugging Equipment Available in Warehouse
G-2
Welding Procedure for Plidco Split Sleeve, Sweet Hydrocarbon Service
G-3
Welding Procedure for Plidco Split Sleeve, Sour Hydrocarbon Service
H-1
Welding Procedure for Full Encirclement Sleeves, Butt Welded, Sweet
Hydrocarbon Service
H-2
Welding Procedure for Full Encirclement Sleeves, Butt Welded, Sour
Hydrocarbon Service
H-3
Welding Procedure for Full Encirclement Sleeve With Strap, Sweet Service
H-4
Welding Procedure for Full Encirclement Sleeve With Strap, Sour Service
H-5
Welding Procedure for Welding Weldolets, Sweet Hydrocarbon
H-6
Welding Procedure for Welding Weldolets, Sour Hydrocarbon
H-7
Welding Procedure for Welding Overlays, Sweet Hydrocarbon
H-8
Welding Procedure for Welding Overlays, Sour Hydrocarbon
H-9
Welding Procedure for Weld Patches, Sweet Hydrocarbon
H-1
Welding Procedure for Thin Walled Pipe Under Pressure, Sweet Hydrocarbon
H-11 Welding Procedure for Socket Weld Fittings
I-2
Welding Procedures, Plidco Weld-Plus Ends, Sweet Hydrocarbon Service
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Pipeline Repair Manual
I-3
Welding Procedures, Plidco Weld-Plus Ends, Sour Hydrocarbon Service
J-1
Procedure for Welding P1 to P1 Carbon Steel Piping, Sweet Hydrocarbon, Single
V Groove (less than 2-7/8" Diameter and less than 3/16 inch wall thickness)
J-2
Procedure for Welding P1 to P1 Carbon Steel Piping, Sour Hydrocarbon, Single
V Groove (less than 2-7/8" Diameter)
J-3
Procedure for Welding P1 to P1 Carbon Steel Piping, Sweet Hydrocarbon, Single
V Groove (greater than 2-7/8" Diameter)
J-4
Procedure for Welding P1 to P1 Carbon Steel Piping, Sour Hydrocarbon, Single
V Groove (greater than 2-7/8" Diameter)
J-5
Procedure for Welding P1 to P1 Carbon Steel Piping, Sweet Hydrocarbon,
Double V Groove (3/8 to 3/4 inch thickness)
J-6
Procedure for Welding P1 to P1 Carbon Steel Piping, Sour Hydrocarbon, Double
V Groove (3/8 to 3/4 inch thickness)
K-1
Welding Procedures for Branch Connections
K-2
Welding Procedure for Saddles for Sweet Hydrocarbon Service
K-3
Welding Procedure for Saddles for Sour Hydrocarbon Service
K-4
Welding Procedure for Stopple Fittings, Sweet Hydrocarbon Service
K-5
Welding Procedure for Stopple Fittings, Sour Hydrocarbon Service
R-1
Procedure for Determining the Cause of a Failure/Defect
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Pipeline Repair Manual
Other Specifications
This manual is based on the following Codes and Practices. Where additional information is required,
the latest edition of the following may be referenced:
API 1104:
Welding of Pipelines and Related Facilities
API RP1107:
Pipeline Maintenance Welding Practices
API 5L:
Specification For Line Pipe
API 2201:
Procedures For Welding or Hot Tapping on Equipment Containing
Flammables
ASME B31.G:
Manual For Determining The Remaining Strength of Corrosion in Pipelines
ASME B31.4:
Liquid Transportation Systems For Hydrocarbons, Liquid Petroleum Gas,
Anhydrous Ammonia and Alcohols
ASME B31.8:
Gas Transmission and Distribution Piping Systems
ASME Section IX:
Welding and Brazing Qualifications
National Oil Corporation
GES R.3:
Pipeline Welding and Repairs
GES I.5:
Acceptance Criteria For Non Destructive Testing
GES 7:
Non Destructive Testing
GES W.3:
Post Weld Heat Treatment of Material
GES 6:
Storage and Control of Welding Consumables
Sirte Oil Company:
BP 19-6-1:
Facilities for Corrosion Monitoring in Production and Process Equipment
(Rev. 8)
BP 19-1-1:
Paint and Protective Coatings, Rev. 8
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Pipeline Repair Manual
PIPELINE REPAIR PROCEDURES (Page 1 of 1)
I.
PRODUCTION DIVISION RESPONSIBILITIES IN THE EVENT OF A LEAK ON A
CRUDE OIL OR GAS TRANSMISSION PIPELINE
3. The Field Superintendent will advise: (a) the Production Department Manager, (b) Fire and
Safety Division, (c) Maintenance Division, (d) Corrosion Protection Division, (e) Local
Ministry of Petroleum representative and (f) Security Division.
5. Meet with the Maintenance and Corrosion Protection Divisions and decide on the cause of
failure and the type of repair to be made.
PREFACE
I.
INTRODUCTION
A.
FACTORS TO CONSIDER IN PIPELINE REPAIR
1. There are a variety…
2. A primary objective of this manual is to provide guidelines for sufficient analyses of
failures to determine appropriate remedial action programs to prevent re-occurrence of
similar failures. All information gathered on site should be included in the
Metallurgical and Inspection report.
3. Upon discovery of a leak, a detailed examination should be made to determine the
extent and cause of the failure. The procedures outlined in Appendix R-1 should be
used as a guidelines.
B.
PIPELINE INSPECTION INTERVAL
6. Internal corrosion control via corrosion monitoring devices (probes and coupons), ultrasonic
(UT) thickness surveys and visual inspection shall be demonstrated by Metallurgical and
Inspection for all major pipelines. Ultrasonic surveys should be conducted by Metallurgical
and Inspection every six (6) months at inspection pits, valve pits, launchers, receivers, dead
legs, etc. (i.e., any exposed piping). All significant thickness variances should be reported to
operations and Corrosion Protection Division Engineering Group immediately after they are
detected.
Upon discovery of a defect that may be of significant size, a detailed examination should be
undertaken to determine the cause and extent of the defect. The examination should be
carried out only after the line pressure is reduced to a level no greater than 80% of the
pressure level a the time the defect was discovered. Refer to Appendix R-1 Procedure For
Determining The Cause of a Failure/Defect as a guideline for this examination procedure.
8. Internal corrosion monitoring electronic probe readings should be taken by Metallurgical and
Inspection (CM & CI) technicians twice monthly. Any significant deviations from acceptable
levels (<2mpy) should be rechecked in two (2) days and if variance is repeated, the deviation
should be reported to Corrosion Protection Division Engineering Group immediately. The
corrosion engineer in charge will then recommend any appropriate steps to rectify the
situation.
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Pipeline Repair Manual
C.
INTRODUCTION TO COMPANY PIPELINE REPAIR MANUAL
These procedures … personnel performing the repairs.
All cutouts should be undertaken as per the guidelines outlined in Appendix R-1 Procedure
for Determining the Cause of a Failure/Defect.
If the leak is not to be cut-out, but is to be sleeved, the guidelines in Appendix R-1
Procedure For Determining The Cause of a Failure/Defect should be followed.
If a failure requiring repair is located such that corrosion monitoring devices, currently in
place, require removal prior to or during the repair, only the qualified Metallurgical and
Inspection (CM & CI) technicians should remove and re-install such devices.
If the failure has occurred at a CM facility, the CM facility should be replaced. Contact
Corrosion Protection Division Engineering Group for advice on the selection of a new
location or type of facility to minimize risk of a re-occurrence of the failure.
Replacement pup-joints should be pre-tested as per guidelines outlined in Appendix A-2
Hydrostatic Testing Procedures
1. Crude Oil Pipelines … repaired by welding a pre-tested pup into the line.
2. Gas pipelines and normally crude oil pipelines or flow lines…
4. Under the following conditions, gouges, grooves, dents and corrosion shall be repaired by:
a)
b)
c)
d)
weld overlay or Plidco full encirclement sleeve, (Appendixes G-2,3; H-7,8)
a butt welded full encirclement sleeve (Appendixes H-1,2)
a strap bonded full encirclement sleeve. (Appendixes H-3,4)
Isolated pitting may be ground out to a gradual contour to remove any notches and
the ground area, not less than two inches (50 mm) in length, shall be filled by
welding. (WPS Overlay, Appendix J-5)
Conditions:
i) gouges and grooves having a depth between 12% and 33% of the nominal pipe
wall thickness (If the defect exceeds 33% of the pipe wall then weld overlay shall
not be used.)
ii) dents that have a depth exceeding 2 per cent of the nominal pipe wall diameter
iii) corrosion that exceeds the limits of Table 3, API 31.G
iv) Pipe not carrying gas may be repaired using a cover patch. (WPS-Patch)
v) Weld overlay shall not be used on pipe operating at more than 40 % of the
SMYS.
vi) Strap bonded sleeves should not be used if the sleeve is to contain line pressure.
5. Leaks in crude oil, two phase and gas pipelines … by installing a "Plidco Split Sleeve" or
"Weld End Sleeve".
delete:
Split sleeves are especially useful … welds.
8. Stopple Plugging Equipment … available in warehouse is listed in Appendix E.
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Pipeline Repair Manual
II.
OIL PIPELINE REPAIRS
A.
PREPARING SITE FOR REPAIR
1. If a leak is reported in a pipeline located alongside…
2. The following personnel are to be advised immediately:
a) Production Manager
b) The appropriate Field or District Superintendent as applicable.
e. Corrosion Protection Division Superintendent or his Metallurgical and Inspection field
representatives.
f. Security
6. De-pressurize and drain … Follow pipeline repair procedures as outlined in Sections IV and
V for…
8. If there is any doubt…
a) If a 1/4" hole is to be drilled within the damaged section of pipe, care
should be taken not to disturb the damaged area if at all possible as
this may debilitate the effectiveness of the failure analysis and a "Smith
plus clamp"…
b) If a gauge … in service is to be followed (see Sections IV and V for
details). Before…
B.
MOBILIZE MANPOWER EQUIPMENT AND MATERIALS
9. The pre-tested section of … if required by the Metallurgical and Inspection
inspector after the pipe is cut to the length required and before it is dispatched to
the field when requested. See…
C.
EXCAVATION PROCEDURES FOR CRUDE OIL PIPELINES
D.
DECIDING THE TYPE OF REPAIR TO BE MADE
1. After determining the cause of the failure/defect the Operations…
E.
REPAIR OF GOUGES, GROOVES, PITTING AND DENTS USING FULL
ENCIRCLEMENT SLEEVES, WELD OVERLAY, OR PATCHES
1. Subject to the following conditions; gouges, grooves, dents and corrosion shall
be repaired by:
a)
b)
c)
d)
weld overlay or Plidco full encirclement sleeve, (Appendixes G-2,3)
a butt welded full encirclement sleeve (Appendixes H-1,2)
a strap bonded full encirclement sleeve. (Appendixes H-4,5)
Isolated pitting shall be ground out to a gradual contour to remove any notches and
the ground area, not less than two inches (50 mm) in length, shall be filled by
welding. (WPS Overlay, Appendix J-5)
Conditions:
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Pipeline Repair Manual
i) gouges and grooves having a depth between 12% and 33% of the nominal pipe
wall thickness shall be repaired using full encirclement sleeves or weld overlay
(If the defect exceeds 33% of the pipe wall then weld overlay shall not be used.)
ii) dents that have a depth exceeding 2 per cent of the nominal pipe wall diameter
shall be repaired using a full encirclement sleeve
iii) corrosion that exceeds the limits of Table 3, API 31.G
iv) Pipe, with a maximum yield strength of 40 ksi, operating at less than 20% of the
specified minimum yield stress (SMYS) may be repaired using a cover patch.
(WPS-Patch)
v) Weld overlay shall not be used on pipe operating at more than 40 % of the
SMYS.
vi) Strap bonded sleeves should not be used if the sleeve is to contain line pressure.
3. Metallurgical and Inspection Group will obtain a Work Permit to UT and MT or PT
inspect the full circumference of the pipe to determine if a full encirclement sleeve is
required.
(a) There are to be no pits, laminations or imperfections of any kind and there shall be
sufficient acceptable parent metal thickness as defined by API B.31G to weld the
sleeve to the pipe … Any defects detected shall be noted in the Metallurgical and
Inspection report.
(b) If the pipeline has been carrying crude containing hydrogen sulfide, then consult
with Corrosion Protection Division, Engineering Group to determine if bake out
and post weld heat treatments are required. If heat treatments are required they
should be applied using the guidelines found in Section VII.
4. Cut full encirclement sleeve from steel of the same material specification and nominal
wall thickness plus 1/8" as the pipeline that is being repaired. The backing strip may be
made of any material in the same P-number group as the parent pipe material. If a
backing strip is not required (the sleeve can be welded to the pipe) then the sleeve
thickness shall be equal to the nominal thickness of the pipe.
5. Prior to work being done on lines under pressure, the safety inspector shall approve the
minimum flow rates and sign the Hot Work Permit.
8. Clean, prime … sleeve. If a corrosion monitoring facility is installed in the repair section,
care must be taken to protect the ends of the electronic probe from damage from either
cleaning by blasting or the coating applications.
F.
REPAIR OF LEAKS IN CRUDE OIL PIPELINES
It is important to determine the cause of the failure using guidelines in Appendix R-1 prior
to initiating the following repair procedures.
If a corrosion monitoring facility is attached to the failed section of pipe to be removed,
ensure that the Metallurgical and Inspection (CM & CI) technicians are informed to
remove the probe/device prior to any work being undertaken.
If a corrosion monitoring access fitting is attached to the failed section of pipe and has to be
removed to effect repairs, it must be replaced with a similar access fitting in an area outside
of the repair sleeve.
1. Minor leaks … are stocked by the company.
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Pipeline Repair Manual
6. Normally the…
b) If the pipeline has been carrying sour crude, then consult with Corrosion Protection
Division, Engineering Group to determine if bake out and post weld heat treatments
are required. If heat treatments are required they should be applied using the
guidelines found in Section VII.
7. Clean , prime … from the pipe. If a corrosion monitoring facility is installed in the repair
section, care must be taken to protect the ends of the electronic probe from damage
from either cleaning by blasting or the coating applications. Drive two…
G.
REPAIRING FAILURES IN CRUDE OIL PIPELINES 10 INCHES AND LARGER
USING WELD PLUS ENDS
It is important to cutout the failed section and preserve it using the procedures outlined in
Appendix R-1.
If a corrosion monitoring facility is attached to the failed section of pipe to be removed,
ensure that the Metallurgical and Inspection Group (CM & CI) technicians are informed to
remove the probe/device prior to any work being undertaken.
If a corrosion monitoring access fitting is attached to the failed section of pipe to be
removed, it must be replaced with a similar access fitting in the same location as the
removed fitting.
2. Cold Cut Pipe:…
b) Select cut points. The … circumferential butt weld.
delete:
Metallurgical and Inspection … in sound pipe.
insert:
The area selected for cutting shall be UT and MT or PT inspected before
cutting begins. Any additional defects detected shall be noted in the
Metallurgical and Inspection Group report.
3. If the pipeline … avoid spontaneous ignition by continuously wetting … until the end is
sealed.
4. Inspect integrity … pipe has been removed (see Appendix R-1), the ends where the joints are
to be made are to be UT and MT or PT inspected and approved by the Metallurgical and
Inspection inspector. Any additional defects detected must be noted in the Metallurgical
and Inspection report.
6. Install pre-tested…
j) If the pipeline has been carrying sour crude, then consult with Corrosion Protection
Division, Engineering Group to determine if bake out and post weld heat treatments
are required. If heat treatments are required they should be applied using the
guidelines found in Section VII. The temperature should not exceed 450 degrees F so
as not to damage the weld plus end packing rings.
k) After heat … and re-inspect using UT and MT or PT the circumferential … is to
witness the UT and MT or PT survey of the weld area. Any further defects detected
must be noted in the Metallurgical and Inspection report. If further defects are
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Pipeline Repair Manual
noted, the procedure must be started again from point 3 above at a new location
outside of the defect area.
7. Return to service.
a) Remove all … pipeline as possible. Re-install all corrosion monitoring probes/devices
that may have been removed.
f) Obtain hot … in accordance with API 1107 - see…
g) Any connections … in item 7 (a) above, except corrosion monitoring access fittings,
are to be …. back welded. All corrosion monitoring access fittings are to be installed
as per the guidelines outlined in the Basic Practice BP 19-6-1 (Rev. 6).
j) Clean, prime and wrap pipe. If a corrosion monitoring facility is installed in the repair
section, care must be taken to protect the ends of the electronic probe from damage
from either cleaning by blasting or the coating applications. Drive two…
H.
PATCH LINE OPERATING AT OR LESS THAN 20 PERCENT SMYS (36" CRUDE P/L)
1. Criteria for Patching
a) If the maximum … a specific corroded area does not exceed the limits allowed in the
ASME B31.G, clean the area. Apply…
b) If the maximum … in a specific corroded area exceeds the limits allowed in ASME
B31.G, clean area … joint design shall be according to WPS PATCH, attached.
2. Application of External Coating
- If a corrosion monitoring facility is installed in the repair section, care must be
taken to protect the ends of the electronic probe from damage from either
sandblasting or applications of coatings.
- Blast clean the pipe…
3. Installation of Welded Steel Patches
a) delete all of paragraph. Patches may be made from any P1 carbon steel pipe
c) Welding Specifications: … patch to patch butt welds shall be in accordance with
Appendix H-10, Pipeline…
edit drawing attachment 1
delete: For extended patch lengths … the following applies
delete: For patch to patch … design shown below.
delete: the rest of the information below
III.
GAS PIPELINE REPAIRS
delete: Further to standardize … materials
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Pipeline Repair Manual
B.
MOBILIZE MANPOWER EQUIPMENT AND MATERIALS
EXCAVATION PROCEDURE FOR GAS PIPELINES
15. The pre-tested section of … if required by the inspector after the pipe is cut to the length
required and before it is dispatched to the field. See…
C.
EXCAVATE
3. Excavation of Ruptures
f) As soon as … the wrapping and have Metallurgical and Inspection conduct … survey
around the circumference of the pipe. If acceptable parent metal of the required
thickness, as determined according to API B31.G, Part 3, cannot be…
D.
DECIDING THE TYPE OF REPAIR TO BE MADE
1. After determining the cause of the failure/defect the Operations…
2. Injurious gouges, … of comparable pipe (see [E] 1. following for details).
E.
REPAIR OF GOUGES, GROOVES, PITTING AND DENTS USING FULL
ENCIRCLEMENT SLEEVES OR WELD OVERLAY
1. Under the following conditions, gouges, grooves, dents and corrosion shall be repaired
by:
a) weld overlay or Plidco full encirclement sleeve, (Appendixes G-2,3)
b) a butt welded full encirclement sleeve (Appendixes H-1,2)
c) a strap bonded full encirclement sleeve. (Appendixes H-4,5)
NOTE: Isolated pitting repair is not allowed.
Conditions:
i) gouges and grooves having a depth between 12% and 33% of the nominal pipe
wall thickness. (If the defect exceeds 33% of the pipe wall then weld overlay
shall not be used.)
ii) dents that have a depth exceeding 1/4" on pipe 12-3/4" outside diameter and
smaller and 2 per cent of the nominal pipe wall on pipes that are greater than
12-3/4" diameter.
iii) corrosion that exceeds the limits of Table 3, API B31.G
iv) Strap bonded sleeves should not be used if the sleeve is to contain line pressure
v) Isolated pitting shall be ground out to a gradual contour to remove any notches
and the ground area, not less than two inches (50 mm) in length, shall be filled
by welding. (WPS Overlay, Appendix J-5)
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Pipeline Repair Manual
vi) Weld overlay shall not be used on pipe operating at more than 40 % of the
SMYS…
3. Metallurgical and Inspection will obtain a Work Permit to UT and MT or PT inspect
the full circumference of the pipe … There are to be no pits, laminations or imperfections
of any kind and there shall be sufficient acceptable parent metal thickness as determined
in accordance with API B.31G to accept the circumferential fillet weld where it is to be
made … Any further defects detected must be noted in the Metallurgical and Inspection
report.
4. If the pipeline has been transporting gas containing hydrogen sulfide, , then consult with
Corrosion Protection Division, Engineering Group to determine if bake out and post
weld heat treatments are required. If heat treatments are required they should be applied
using the guidelines found in Section VII.
5. During heat treat … 250 psig for each
Protection, Engineering Group.
1/
16".
These values should … case by Corrosion
NOTE: Pipe, that is under pressure, that has a wall thickness less than 3/16 inch shall
be welded using down hand welding and low hydrogen electrodes should not be
used. (WPS Appendix H-11).
8. After heat … and re-inspect using UT and MT or PT the circumferential … is to witness the
UT and MT or PT survey of the weld area. Any other defects detected must be noted in
the Metallurgical and Inspection report. If other defects are noted, the procedure must
be started again from point 3 above at a new location outside of the defect area.
11. Clean, prime … with Appendix O-1. If a corrosion monitoring facility is installed in the
repair section, care must be taken to protect the ends of the electronic probe from
damage from either blast cleaning or applications of coatings.
F.
REPAIR OF LEAKS IN GAS PIPELINES
It is important to determine the cause of the failure using guidelines in Appendix R-1 prior
to initiating the following repair procedures.
If a corrosion monitoring facility is attached to the failed section of pipe to be removed,
ensure that the Metallurgical and Inspection (CM & CI) technicians are informed to
remove the probe/device prior to any work being undertaken.
If a corrosion monitoring access fitting was attached to the failed section of pipe has to be
removed to effect repairs, it must be replaced with a similar access fitting in an area outside
of the repair sleeve.
2. During Excavation … by some temporary means - wood plug, self tapping screw, Smith
clamp etc. (use Appendix R-1 to try to determine the cause of the failure before
damaging the pitted area) - in order to…
After removing the wrapping including primer, determine the cause of the failure using
the guidelines in Appendix R-1 before preparing the surface for repair. Obtain…
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Pipeline Repair Manual
3. Metallurgical and Inspection will obtain a Work Permit to UT and MT or PT inspect the
full circumference of the pipe. The Maintenance … There are to be no pits, laminations or
imperfections of any kind and there shall be sufficient acceptable parent metal thickness
according to API B.31G to accept the circumferential fillet weld where it is to be made …
in co-operation with the Metallurgical and Inspection Group … Any further defects
detected must be noted in the Metallurgical and Inspection report.
4. If the pipeline has been transporting gas containing hydrogen sulfide, then consult with
Corrosion Protection Division, Engineering Group to determine if bake out and post
weld heat treatments are required. If heat treatments are required they should be
applied using the guidelines found in Section VII.
5. During heat treat … These values should … case by Corrosion Protection, Engineering
Group.
NOTE:
Pipe, that is under pressure, that has a wall thickness less than 3/16 inch shall
be welded using down hand welding and low hydrogen electrodes should not
be used. (WPS Appendix H-11)
8. After heat … and re-inspect using UT and MT or PT the circumferential … is to witness the
UT and MT or PT survey of the weld area. Any other defects detected must be noted in
the Metallurgical and Inspection report. If other defects are noted, the procedure must
be started again from paragraph 3 above at a new location outside of the defect area.
10. Install either…
a) Clean pipe…
viii) If corrosion monitoring probes/devices were removed, contact Metallurgical
and Inspection Group (CM & CI) technicians to re-install the probes/device.
b) If a Smith…
viii) If corrosion monitoring probes/devices were removed, contact Metallurgical
and Inspection Group (CM & CI) technicians to re-install the probes/device.
11. Clean, prime … with Appendix O-1. If a corrosion monitoring facility is installed in the
repair section, care must be taken to protect the ends of the electronic probe from
damage from either blast cleaning or applications of coatings.
G.
REPAIR OF RUPTURE IN GAS PIPELINES
1. Outline
This procedure, along with the guidelines in Appendix R-1, are to be followed … to the
next phase.
If a corrosion monitoring facility is attached to the failed section of pipe to be removed,
ensure that the Metallurgical and Inspection (CM & CI) technicians are informed to
remove the probe/device prior to any work being undertaken.
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Pipeline Repair Manual
If a corrosion monitoring access fitting is attached to the failed section of pipe and has
to be removed to effect repairs, it must be replaced with a similar access fitting in the
same area as the removed access fitting.
2. Line and Grade Survey
As soon as … balloon nozzles have been established by UT and MT, or PT during
excavation…
3. Phase I
a) Phase I…
v) Obtain a Hot Work Permit and re-inspect using UT and MT or PT the area …
witness the UT and MT or PT survey of the weld area … who shall be a company
employee. Any additional defects detected must be noted in the Metallurgical
and Inspection report.
b) Weld Nozzles onto Pipe
iii) If the longitudinal … grind the weld cap flush with the wall…
iv) Weld nozzle … delete:
in place.
c) Hot Tap Nozzles
d) If necessary … using nitrogen gas.
e) After condensate…
f) Electrically bridge…
4. Phase II
Insert Cylindrical … and remove damaged section of pipe following guidelines set out in
Appendix R-1. Refer to…
b) Cold Cut and Remove Damaged Section of Pipe
ii) Allow pipe to cool to at least 250F to minimize possible pipe end deformations
due to differential temperatures during cold cut (Ref.: ASME Section VIII,
Division 1), before cold…
iv) Remove damaged section of pipe and wash open ends of pipeline back to … from a
fog nozzle. Refer to Appendix R-1 Procedure for Determining the Cause of a
Failure/Defect for failed section recovery procedures. Scrape any…
vi) Metallurgical and Inspection Group are to re-inspect the integrity of the pipe ends
using UT and MT or PT where … There are to be no pits, laminations or
imperfections of any kind and there shall be sufficient acceptable parent metal
thickness as determined according to API B.31G to accept circumferential welds
where the butt welds are to be made.
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Pipeline Repair Manual
vii) Request that … If a pre-tested section of pipe is to be cut, the M & I inspector will
decide whether a retest is required after the pipe is cut to the length required
and before it is dispatched to the field when requested. See…
6. Phase IV
Install Replacement Section of Pipe. If a corrosion monitoring access fitting is attached to
the failed section of pipe and has been removed to effect repairs, it must be replaced
with a similar access fitting in the same area as the removed access fitting. Refer to…
7. Phase V
Return Repaired Pipeline to Service. Refer to…
e) If a corrosion monitoring probe/device was removed, ensure that the Metallurgical
and Inspection Group (CM & CI) technicians are informed to re-install the
probe/device prior to repressurizing the line.
10. Clean, prime … with Appendix O-1. If a corrosion monitoring facility is installed in the
repair section, care must be taken to protect the ends of the electronic probe from
damage from either blast cleaning or applications of coatings.
13. Referring to Appendix R-1 Procedure for Determining the Cause of a Failure/Defect for
failed section recovery procedures, send damaged … Central Shops, Brega. State on work
order that Central Shops is to contact Corrosion Protection Division Engineering Group to
inspect…
IV.
ATTACHING CONNECTION TO PIPELINE
This section must be completed for the manual rewrite as it is referred to several times
throughout the manual.
All corrosion monitoring access fittings are to be installed as per the guidelines set out in
the Basic Practice BP 19-6-1 Facilities for Corrosion Monitoring in Production and Process
Equipment.
V.
HOT TAP PROCEDURE
A.
PREFACE
The hot tap technique … in a connection.
The exception for this technique is where a corrosion monitoring or chemical injection high
pressure access fitting is to be installed on the line. In this case, the Metallurgical and
Inspection (CM & CI) technicians have the hot tapping equipment and the expertise to
operate this equipment. No other form or hot tapping is acceptable for high pressure access
fittings.
In the case of low pressure access fittings for corrosion monitoring, standard hot tapping
procedures shall be used to install the nipple and valve required.
Refer to the Basic Practice BP 19-6-1 Facilities for Corrosion Monitoring in Production and
Process Equipment for more details.
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Pipeline Repair Manual
C.
RESPONSIBILITIES
2. The Senior Operations Supervisor shall consult with representatives from Technical
Department, Corrosion Protection Division, Maintenance and Safety…
b) Equipment is mechanically sound and that there are no pits, laminations or
imperfections of any kind and there shall be sufficient acceptable parent metal
thickness, as determined in accordance with API B.31G, to accept welds where the
hot tap is to made.
NOTE: Materials below…
c) Metal inspection test procedures (including, but not limited to radiography or UT and
MT or PT) are established…
f) If the pipeline has been transporting fluid containing hydrogen sulfide, then consult
with Corrosion Protection Division, Engineering Group to determine if bake out
and post weld heat treatments are required.
k) If heat treatments are required they should be applied using the guidelines found in
Section VII.
i) During heat treatment operations, the gas flow must be reduced to practically no
flow conditions and pressure reduced to 350 psi. No spheres should pass and no
condensate should be laying in the work area during heat treat and welding
operations. During welding gas flow o approximately 3 lineal feet/second is to be
maintained but operating pressures are not to exceed 350 psig for a wall
thickness of 3/16 inch and may be increased 250 psig for each additional 1/16
inch of wall thickness. These values should be confirmed in each particular case
by the Corrosion Protection, Engineering Group.
NOTE: Pipe, that is under pressure, that has a wall thickness less than 3/16 inch
shall be welded using down hand welding and low hydrogen electrodes
should not be used. (WPS Appendix H-11)
ii) After heat treatment (bake out) of the pipe, obtain a Hot Work Permit and reinspect using UT and MT or PT the circumferential areas around the pipe where
the fillet weld are to be made to attach the sleeve to the pipe. If imperfections
develop during the heat treatment, the repair section may have to be lengthened,
or a decision may be made not to fillet weld either type of sleeve to the pipe. The
Maintenance Supervisor is to witness the UT and MT or PT survey of the weld
area. Any further defects detected must be noted in the Metallurgical and
Inspection Group report. If additional defects are detected, the inspection
procedure must be started again at a new location outside of the defect area.
5. The Senior…
c) Corrosion Protection Division shall schedule the necessary metal inspections.
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Pipeline Repair Manual
HOT TAP PROCEDURE
CHECK OFF AND REPORTING FORM
3. Line inspection before welding nozzle on line:
Type of Test(s) Performed
Signature/PN of M & I Inspector
10. Test nozzles…
Signatures of: Maintenance…
Operations…
Witnessing M & I Inspector
Safety Department
VI.
STOPPLE PLUGGING PIPELINES
STOPPLE FITTING INSTRUCTION SHEET
RECOMMENDED WELDING PROCEDURES (WPS STOPPLE)
For best results…
If at all possible … collect moisture. The electrodes SHALL be kept … should be completed as
efficiently…
The drawing on page VI-4 should include a 1/4" hole, drilled and tapped for venting.
Delete: Welding Sequence and paragraphs : A, B, C
These recommendations … convenience and assistance.
delete: TDW. Inc. cannot … price of the fitting.
VII.
HEAT TREATMENT OF PIPING
NOTE: The following sections replace only page VII-1 in the manual. All other pages remain as
is in the manual
A.
BAKEOUT
1. This heat treatment procedure shall be used when the steel component to be welded has
been exposed to wet hydrogen sulfide service. (Wet H2S service is defined as those
processed streams of environments that have a separate water phase containing more
than 50 ppm of H2S.)
2. The Corrosion Protection Division shall be consulted before welding, if the welding
procedure does not include bake out of steel that has been in sour liquid service.
Steel Thickness
Bakeout Temperature
95C (204F)
Page 16
Hold/Soak Time
10 Hours
Pipeline Repair Manual
0.125" to 0.375"
0.375" to 0.575"
150C (302F)
200C (395F)
95C (204F)
150C (302F)
200C (395F)
5 Hours
2 Hours
20 Hours
10 Hours
4 Hours
4. Piping connections that are 1-½ inch and smaller diameter may be baked out at a
temperature between 345C - 371C (650F - 700F) and held for 20 minutes.
5. The Corrosion Protection Division shall be consulted when a bake out procedure is
required for a steel component that is greater than 0.575 inches thick.
6. The steel component shall be heated according to the bake out procedure for a
minimum of 3 inches or 6T, which ever is the greater, on each side of the centerline of
the weld.
7. The temperature of the area to be bake out shall not vary by more than 10C (18C).
B.
PREHEAT TREATMENT
1. The surfaces of the steel component shall be preheated above the specified minimum
temperature for a band width to 5 times the thickness of the component being welded
but not less than 3 inches on each side of the center line of the weld and in advance of
the welding.
2. Continuous preheat shall be applied on all components that have a thickness greater
than 1-½ inches.
3. Temperature sensitive crayons shall be used to measure the weld face temperature for
piping components. (NOTE: When fluid is flowing through the pipe additional heat by
oxyacetylene torch is often required).
C.
POST WELD HEAT TREATMENT
1. A minimum circumferential band width of 5T but not less than 2 inches on each side of
the weld center line shall be heated to the minimum soak temperature.
2. Pipe larger than 8 inches in diameter shall have a thermocouple attached to the top and
bottom of the pipe.
3. Care shall be taken to assure that the pipe is properly supported and free to expand
during PWHT.
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Pipeline Repair Manual
Pipeline Repair.skd
VIII.
ELECTRODE HANDLING
A.
WELDING CONSUMABLES HANDLING
1. Welding wire/rod shall be stored in a dry area and any corrosion on the wire shall be
cleaned off by scraping before use
2. Electrodes
a) Upon receipt of a consignment of electrodes, the stockman shall examine the
containers for damage. All electrodes except E6010 or E6011 electrodes in damaged
containers or containers that have the seal broken, shall be set aside for
reconditioning.
b) Electrodes that have cracks or color variances in the coating shall be discarded.
c) Electrodes in any containers that are unidentifiable shall be discarded.
d) Electrodes requiring reconditioning shall be reconditioned according to the
manufactures recommendations and stored to the requirements described in ASME
Section II, Part C, Table A1.
B.
ADDITIONAL REQUIREMENTS FOR LOW HYDROGEN WELDING ELECTRODES
1. Electrodes that have been exposed to the atmosphere (outside ovens) for more than two
hours shall be reconditioned. Damp electrodes will be automatically set aside for
reconditioning.
2. Electrodes shall be stored according to the following procedure:
a) Low hydrogen electrodes must not be stored in ovens that hold electrodes of other
classifications.
b) No other items shall be in ovens that hold low hydrogen electrodes.
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Pipeline Repair Manual
c) Electrodes shall not be reconditioned more than three times.
3. Electrodes to be used on site shall be taken from the storage oven and transported in
quivers (portable heaters) heated to a minimum temperature of 70C.
4. At the end of each operation or shift, quivers and unused electrodes shall be returned to
the electrode store, the stockman shall ensure that the electrodes are clearly identifiable,
the coatings are free of chips and have a consistent color. Electrodes that have a furry
surface on the coating, usually white, shall not be used for extremely critical work.
IX.
REMOVAL OF DETRIMENTAL MAGNETIC FIELDS AT PIPELINE TIE-INS
NOTE:
CPD strongly recommends the installation of this section into the manual. The
majority of this section should be provided by E&DD and PCD. CPD will
provide any assistance required related to welding procedures, metallurgical
problems, etc.
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Pipeline Repair Manual
PIPELINE REPAIR PROCEDURE
APPENDIX A-1
LIST OF PIPELINES IN SERVICE
AND
INHIBITED PRETEST SECTIONS REQUIRED
NOTE:
The word GAS should be eliminated from the title as oil pipelines are also
included in this section.
This section requires substantial revision to include 30" gas and 6" condensate lines from
all fields, 34" Main Gas Sales Line.
Engineering and Design Division should also check with all production superintendents to
ensure that all field trunklines (gas, oil and condensate) are included in this section.
The two phase oil/water line now has both 20" and 24" diameter piping sections.
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Pipeline Repair Manual
PIPELINE REPAIR PROCEDURE
APPENDIX A-2
HYDROSTATIC TESTING PROCEDURES
NOTEs: This section should not be limited only to inhibitors for hydrostatic testing but should
include all required parameters to perform a proper hydrostatic test, either in the shop
or in the field.
Hydrostatic testing of pre-tested pup-joints and line replacement sections shall follow
the procedures as outlined in the appropriate code with the following addendum:
Inhibition of Pre-tested and Field Installed Pipe Sections
WATER:
The source of the water should adhere to the guidelines set out in point (3) below. Generally, the
water used for hydrostatic testing should be potable or low TDS water. Seawater and high brine
content waters should be avoided if at all possible.
Water must be chemically treated to avoid corrosion and bio-contamination of the line. The
amount of chemical inhibitor will vary depending on test duration, water analysis and source.
Three (3) different inhibitors and three (3) standard time periods and their appropriate
concentrations for standard potable or low TDS water are included below.
RECOMMENDATION:
(1) Chemical:
Exposure
Application Rate
Time
(ppm)
Up to 1 Week
400 ppm
Product Name
Baker Cronox
669
or Equivalent
Type
CI, OS &
Biocide
Baker Cronox
669
or Equivalent
CI, OS &
Biocide
1 Week up to
2 Months
500 ppm
Baker Cronox
669
or Equivalent
CI, OS &
Biocide
2 Months up
to
1 year
2000 ppm
CI -- Corrosion Inhibitor
Volume
Required
To be
Calculated
(17 US
gal/Tbbls)
To be
Calculated
(21 US
gal/Tbbls)
To be
Calculated
(84US
gal/Tbbls)
OS -- Oxygen Scavenger
(2) The chemical should be continuously mixed with the water while filling the line.
Slugging the chemical ahead of or following the filling of the line is unacceptable as this
does not ensure adequate mixing of the inhibitor into the water throughout the line.
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Pipeline Repair Manual
(3) Precautions are required to avoid contamination of the line; and water with substances
which may contain bacteria (organic matter, mud, dirt, stagnant surface water,
seawater, untreated tank waters, etc.) should be avoided.
(4) If a different product to the above-mentioned recommendations is to be used, Corrosion
Protection Division Engineering Group must be contacted as application rates may vary
from product to product.
(5) Adequate precautions for proper disposal of the hydrotest fluid must also be
considered. The addition of the inhibitors makes the hydrotest fluid toxic (MSDS are
available from Fire & Safety Division). Disposal into areas where the water could be
consumed by man of animals must be avoided. Contact the Environmental Group for
assistance.
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Pipeline Repair Manual
PIPELINE REPAIR PROCEDURE
APPENDIX C-1
LIST OF TOOLS AND MATERIALS REQUIRED
FOR PIPELINE REPAIRS
GENERAL FOR ALL SIZES OF PIPE
Item
Quantity
Description
49
6 Rolls
Tape: Masking
51
1 ea.
Pit Depth Gauge: Needle Point for Measuring Corrosion
Pitting Depths
52
2 ea.
Fiber Brushes (Not Wire) for Cleaning Damaged Areas of Pipe
for Inspection
53
25.ea.
Large garbage bags
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Pipeline Repair Manual
APPENDIX R-1
PROCEDURE FOR DETERMINING THE CAUSE
OF A FAILURE/DEFECT
I.
INVESTIGATION PRIOR TO DECISION ABOUT REPAIR METHOD
Several important factors should be considered before the investigation begins:
1. Determining the cause of the defect or failure will provide important information in
order to help prevent possible re-occurrences. (A defect is a flaw of such size, shape,
orientation, location or properties as to be rejectable.)
2. Mishandling of defects or failed areas will destroy important evidence used to
determine the cause of the failure. Therefore, wire brushing, hammering and grinding
should be avoided as they may tend to obscure the nature of the defect.
3. Extreme care MUST be taken when investigating a failure prior to commencement of
the repair procedure or valuable information will be permanently lost.
A.
Defects
1. If the repair area has not yet failed (started leaking), this is referred to as a defect.
Defects are usually detected by non-destructive testing (NDT) including, but not limited
to:
Ultrasonic Testing (UT)
Radiography (RT)
Magnetic Particle (MT)
Dye Penetrant (PT)
Visual Observation
2. Guidelines for determining unacceptable corrosion as described in the text of API
B.31G. Allowances for dents and gouges are defined in the appropriate sections of the
Pipeline Repair Manual. Allowances for cracks and laminations that have not yet failed
are not currently defined in this manual; contact the Corrosion Protection Division,
Engineering Group for criteria.
3. If the inspector or custodian is in doubt as to the severity of any defect, he should
contact the Corrosion Protection Division, Engineering Group for clarification.
4. When the appropriate method of repair has been established and work is about to
begin, decrease the pressure below 67% of the level present when the defect was
discovered.
B.
Failures
1. If the repair area has failed, it is generally leaking and has been detected by visual
means.
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Pipeline Repair Manual
2. Any leak on any line is unacceptable and must be repaired.
3. All NDT methods, noted in Section A above, should be used to determine the type and
extent of damage to the pipeline.
C.
Basic Information
The following basic information about the line is required, some of which may be collected
after the repair is completed but most of which must be collected prior to the initiation of
the repair. All information should be completed on the Report Form found at the end of
this Appendix regardless of whether the repair is a cut-out or a sleeve repair.
1. Field
:
Which production facility is responsible for the pipeline in
question.
2. Location
:
Exact description of failure/defect location; i.e. distance
from wellhead, manifold, isolation valve, relative distance
and orientation to welds etc.
3. Pipe Diameter
:
The outside diameter of the pipeline to be repaired.
4. Pipe Material
:
Grade and alloy content of pipeline material.
5. Pipe Schedule
:
To provide the original nominal wall thickness of the pipe.
6. WT (by UT)
:
The wall thickness of the pipe outside of the failure/defect
area (acceptable parent metal area).
7. MOP
:
Maximum operating pressure of the line.
8. Pressure
:
The line pressure at the time the failure/defect was noted.
9. Temperature
:
The line temperature at the time the failure/defect was
noted.
10. Process Fluids
:
The contents of the line; i.e. gas, condensate, oil, water, all,
etc. If combined fluids are in the line indicate components
by per cent.
11. CP
:
Is the line cathodically protected? If yes, the CP M&I
technician should be dispatched to determine if the CP was
on at the time of the failure and at what tap settings.
12. CI
:
Is corrosion inhibitor being injected into the line? If yes, the
CM & CI M&I technician should be dispatched to
determine if the chemical is on and at what rate of injection.
13. Coating
:
Is the line coated? If yes, determine type and condition of
both internal and external coatings. Pay special attention to
coating/wrap disbondment and/or failures.
14. Type of Damage
:
Indicate the type of damage; corrosion / dent / gouge /
cracking / lamination / other and give a brief description of
the failure/defect area.
15. Failure/Defect
:
Indicate whether the damage is due to a mechanical,
welding failure or a defect.
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Pipeline Repair Manual
16. Internal/external
:
Indicate whether the damage is internal or external.
17. Deposits
:
Are there any deposits on the outside or inside of the line?
18. Deposit Description
:
Describe any and all deposits, internal and external, giving
color, consistency, thickness, adherence, etc. Indicate
whether the deposit is a scale (CaCO3 or similar) or a
corrosion product (Fe2O3, FeS, etc.). Is the deposit
magnetic?
NOTE:
19. Sketch Area
D.
It is important not to damage the surface, prior to
determining the cause of the failure. See the appropriate
Sections II and III below for proper procedures for sample
gathering.
:
It is important to sketch the failure/defect area. Include as
much information as possible in the sketch; i.e. distance to
known markers, valves, fittings, welds etc.; note the
orientation of the failure/defect on the pipe; note location
and orientation of subsequent defects detected in the
examination of the repair area; note the location and
density of the deposits (if any); note any coating/wrap
failures and disbondment; note the direction of flow of the
effluent. Use an additional sheet of paper if necessary.
20. Additional Information :
All additional information not previously noted above,
which may be pertinent to the failure investigation should
be noted here. This should include a written description of
the sketch. Any additional items on the line, such as
weights, inspection pits, etc., should also be noted here. If
more space is required, use an addition page.
Excavation and Initial Inspection
Care must be taken when initially excavating the site so as not to cause more extraneous damage
to the failure site and/or destroy evidence as to the cause of the failure. The following guidelines
should be adhered to when excavating and making the initial inspection of the failure to
determine the repair method to be undertaken.
1. When the excavation nears the failure area, it is imperative that shovels, picks, etc. not
contact the failure area. Bristle brooms and/or fiber brushes should be used to clean the
soil of the immediate failure area. Care should be taken not to disturb or remove any
external deposits on the line.
2. NEVER hammer or jam a plug, wooden or otherwise, into a failure to stop the leaking
until the M&I inspector has examined the failure (unless absolutely necessary).
3. Avoid banging the pipe in the excavation area with shovels, picks, hammers, etc. as this
will dislodge any deposits, internal and external, should they exist.
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Pipeline Repair Manual
4. The failure area should not be cleaned with solvents or rags until the Metallurgical and
Inspection inspector has initially viewed the failure area and gathered any pertinent
information.
5. Only organic solvents, such as white petroleum spirits, should be used to clean the
failure area and then only if absolutely necessary to continue the investigation. Never
add acids, caustics, detergents or abrasive cleaners to the failure/defect surface. Only
clean rags should be used to wipe the failure/defect area. Wet, dirty or oily rags should
not be used.
6. If it is necessary to remove the coating/wrapping, care must be taken not to scrape or
mar the immediate failure area. Save any deposits that may be adhered to the
coating/wrap that is removed in a clean envelope or plastic container. Be careful not to
drop samples in the dirt/oil/water.
7. After the failed area has been prepared for visual inspection, use a magnifying glass if
necessary, DO NOT attempt to fit fragmented pieces together or bend or break them
apart. Metal to metal contact on the fracture surface may destroy valuable evidence as
to the cause of the failure. If the failure is to be removed see Section III below for details
on preserving fragments and pipe ends. If the failure is not to be removed but is to be
repaired in-situ, then follow the guidelines in Section II below for gathering maximum
information prior to repairing.
8. Additional NDT may now be undertaken if necessary to determine the type of repair. If
the type of repair has already been decided then follow the guidelines in the
appropriate Section II or III below. Results of all additional NDT should be noted on
the Report Form (even if no further defects were noted).
II.
PROCEDURES FOR DETERMINING THE CAUSE OF A FAILURE/DEFECT
PRIOR TO SLEEVE INSTALLATION
The following procedures should be undertaken only if the pipe is to be repaired in-situ; i.e.
no cut-outs. If cut-outs are to be undertaken, follow the guidelines set out in Section III
below.
NOTE:
It is important to remember that most sleeve installations are temporary repairs.
This means that the failure/defect may be cut out some time in the future and
properly examined. Therefore it is imperative that extreme care be taken to
minimize damage to the failure/defect site while affecting the repair.
1. Before on-site repair is to begin, all results of additional NDT and visual inspections for
the whole repair area should be noted on the Report Form (even if no further defects
were noted).
2. When stripping off coating/wrap, note, label and save, in a clean envelope or plastic
container, a sample of the coating and any deposits found between the coating/wrap
and the pipe. Do not remove the deposits from the coating but, rather, cut out the area
of coating containing a sample of the deposit. Care must be taken not to scrape or
further damage the failure/defect area when removing the coating.
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Pipeline Repair Manual
NOTE:
When cleaning the pipe for further inspection it is important to only use
organic solvents and a clean fiber brush. Wire brushes should NEVER be
used in the failure area.
3. If internal or external deposits exist in the failure area, carefully remove the deposit
and label and save, in a clean envelope or plastic container. Do not wash, clean or wipe
deposits and take care not to drop in dirt/oil/water. If the deposits are tightly adhering
to the pipe surface use whatever force is necessary to remove a sample but note what
methods and how much force was used to remove the deposit.
NOTE:
If the deposit is internal and cannot be easily removed, note all visual/RT
information about the deposit on the Report Form. The use of 15% HCl is
permitted to help determine the nature or the deposit but this should be the
last action taken by the inspector prior to commencing the repair. Be sure to
wash away the acid with copious amounts of water.
4. If the failure/defect is external corrosion, determine the maximum depth of the pitting
in the repair area using a needle point pit depth gauge and note depth(s) on the Report
Form.
5. If the failure/defect is internal corrosion, determine the extent of the corrosion, noting
the distance in all directions to acceptable parent metal by NDT (UT and RT). Also note
the wall thickness at the failure/defect and indicate the gradient to acceptable parent
metal (use a sketch). Note any inclusions, porosity, laminations or cracking in the repair
area on the Report Form. Try to determine and report the most likely cause of the
corrosion; i.e. CO2, bacteria, H2S, underdeposit, etc.
6. Using PT or MT, determine if any additional external cracking is evident in the repair
area and note accordingly on the Report Form.
III.
PROCEDURE FOR PRESERVING THE INTEGRITY OF A CUT-OUT REPAIR
SECTION FOR FAILURE/DEFECT ANALYSIS
The following procedures should be undertaken only if the pipe is to be cut-out. If in-situ
repairs are to be undertaken, follow the guidelines set out in Section II above.
The following guidelines should be adhered to at all stages of the procedure:
1. DO NOT remove any more coating/wrap than is necessary for initial failure
investigation.
2. DO NOT scrape, mar, dent or gouge the failure/defect surface.
3. DO NOT hammer, grind or wire brush in the failure/defect area.
4. DO NOT fit fractured or failed pieces together.
5. DO NOT pry apart, bend or separate partially fractured pieces by any means. LEAVE
THEM INTACT.
6. DO NOT wipe failure/defect area, especially with dirty, wet or oily rags. If the failure
area must be cleaned for further inspection on-site, use only clean rags, appropriate
solvents and a fiber brush when cleaning or handling failed sections.
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Pipeline Repair Manual
7. AVOID touching the failure/defect surface with bare hands. Oils and moistures on
human hands are highly acidic and can destroy evidence.
8. AVOID exposing the failure/defect surface to soil/water/dirt if at all possible.
9. DO NOT under any circumstance put acids, caustics, detergents or inorganic solvents
on the failure/defect surface.
10. LEAVE all deposits intact. Collect any loose deposits; label and place them in a clean,
clearly marked envelope or plastic container.
A.
Prior to Failed Section Removal
1. Perform and record all necessary additional NDT work.
2. Clearly mark the location identifier, 12 o'clock position and direction of flow using a
paint pen. DO NOT use marking pens as they are water/solvent soluble and are easily
removed. Allow sufficient time for the paint to dry before handling or wrapping.
3. Wrap the failed section in clean rags and plastic garbage bags prior to removal from
the excavation pit. Be sure to cover both ends of the pipe with plastic and tape. Be
careful not to tape over the failure/defect area.
B.
Removal of Failed Section
1. Cold Cuts
When cold cutting the failed section for removal, using a Wachs Saw, pipe cutter or
other mechanical device, the following guidelines should be used:
a) The minimum distance to cut the failed section must be at least 3" or 6 times the
wall thickness away from any welds on the pipeline side of the failed section.
b) The minimum distance to cut the failed section must be at least 3" or 6 times the
wall thickness away from the outside limits of the failure/defect on the failed side of
the cut-out.
c) NEVER, for any reason, cut directly through the failure/defect or any associated
weld.
2. Hot Cuts
When hot cutting the failed section for removal or cutting the failed section into smaller
more manageable sections using an oxyacetylene torch, the following guidelines should
be used.
a) The minimum distance to cut the failed section must be at least 6" or 6 times the
wall thickness away from any welds on the pipeline side of the failed section.
b) The minimum distance to cut the failed section must be at least 6" or 6 times the
wall thickness away from the outside limits of the failure/defect on the failed side of
the cut-out.
c) NEVER, for any reason, cut directly through the failure/defect or any associated
weld.
3. After removing the failed section from the pipeline, a small hole may be drilled or
oxyacetylene cut in the 12 o'clock position on the upstream side of the failure at the very
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Pipeline Repair Manual
edge of each pipe segment. A proper wire tag with all pertinent location descriptions
and identifiers can then be attached through this hole.
NOTES: i. The tag should never be installed through the failure hole or twisted
around a fragment piece.
ii. The drilled/cut hole must be at the very edge of the failed section and
must not interfere with or contact the failure/defect or weld in any way.
iii. Be sure of orientation before cutting the holes as they will be used to
determine top of pipe and direction of flow if the paint pen markings are
inadvertently removed.
C.
Prepare Cut-out(s) for Shipment
1. Ensure that fragments are suitably protected from damage during shipment. DO NOT
wrap pipe fragments in wet, dirty or oily rags; use clean rags only and then place in
labeled plastic bags (garbage bags are good for larger pieces).
2. The pipe ends of the removed sections of pipe should be wrapped in plastic and taped
securely in place. Be careful no to tape over the failure/defect area but ensure that the
failure area is also suitably protected.
3. Send all deposits and failed pieces complete with a copy of the Report Form to the
Corrosion Protection Division, Engineering Group. In the case of extremely large
sections of pipe or large diameter piping, send the cut-outs to the Brega Central Shops.
State on work the order that Central Shops is to contact Corrosion Protection Division
Engineering Group for instructions on cutting out the failed section(s) for analysis.
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Pipeline Repair Manual
Metallurgical & Inspection
Pipeline Repair Report Form
Field:
Location:
Pipe Diameter:
in.
Material:
Schedule:
WT (by UT):
in.
MOP:
psi
Process Fluids:
Line Pressure:
psi
CP (y/n): Tap Setting:
Temperature:
CI (y/n): Rate:
o
C
gpd
Coating (Type & Condition):
Type & Desription of Damage:
Corrosion / Gouge / Dent / Cracking / Lamination / Other:
Failure or Defect:
Internal/External:
Deposit Type/Description:
Deposits (y/n):
Scale / Corrosion Product / Other:
Sketch of Failure/Defect Area(s): Note fixed mark points (valves, fittings, etc.) & orientation:
Additional Descriptions, Remarks and Comments:
Page 31