GU-379 Pipeline Emergency Repair Manual Authorised For Issue --/--/---- Signed:........................................................................................ M. Zadjali, UIP CFDH Pipelines The following is a brief summary of the 5 most recent revisions to this document. Details of all revisions prior to these are held on file by the issuing department. Version No. Rev. 4.0 Rev. 3.2 Date Nov 2004 April 2001 Feb. 2001 Author UEL/1 R Harris OIP/31 UEL/1 Scope/ Remarks GRP pipeline section added. Document re-formatted. Electronic copy of Emergency Materials List (Appendix 13) added. Designed as BCD Guideline. Minor textual changes to adapt to GU- format and reference updated. Technical content not reviewed. Rev. 3.1 Rev. 3 June 1999 OIP/4 Updated to reflect changes in responsibilities due to asset based organisation and reformatted to new template. Rev. 2 Mar 1995 AEF/631 Page 2 of 76 GU-379 Pipeline Emergency Repair Manual Table Of Content Authorised For Issue --/--/----.........................................................................................2 1.0 Introduction..................................................................................................................... 1.1 Objective.................................................................................................................5 1.2 Scope.......................................................................................................................5 1.3 Applicable Standards..............................................................................................6 1.4 Definitions and Abbreviations................................................................................6 1.5 Distribution/Target Audience..................................................................................7 1.6 Document Structure................................................................................................7 1.7 Review & Improvement..........................................................................................8 2.0 Emergency Repairs for Carbon Steel Pipelines........................................................... 2.1 Scope.......................................................................................................................9 2.2 Types of defects and its causes................................................................................9 2.3 Causes of Emergency Defects...............................................................................10 2.4 Types of Level I Emergency Defects....................................................................10 2.5 Level-I Emergency Defects...................................................................................11 2.6 Composite Repair: An Alternative Repair Method...............................................29 2.7 Level II Emergency Defects- Injurious non leaking defects.................................30 2.8 Repair organisation...............................................................................................30 3.0 Emergency Repairs for Glass Reinforced Plastic (GRP) Pipelines......................... 3.1 General..................................................................................................................31 3.2 Scope.....................................................................................................................31 3.3 Causes of defects in an operating GRP pipeline system.......................................31 3.4 Defects due to over pressurisation........................................................................31 3.5 Defect categorisation.............................................................................................31 3.6 Repair of Level-I Emergency Defects...................................................................32 3.7 Emergency Repair Procedure Qualification..........................................................36 3.8 Quality Programme during Repair........................................................................36 3.9 Emergency Repair Kit...........................................................................................36 4.0 Emergency Repair of Subsea Carbon Steel Pipelines.............................................. 4.1 General..................................................................................................................38 4.2 Scope.....................................................................................................................38 4.3 Causes of Defects..................................................................................................39 4.4 Level – I Emergency Defects...............................................................................39 4.5 Resources..............................................................................................................41 5.0 Emergency Stock Materials......................................................................................... 5.1 Philosophy.............................................................................................................42 5.2 Loaction and Quantities of Emergency Stock Materials.......................................42 6.0 Safety.............................................................................................................................. 6.1 Safety requirements during repair of emergency defects......................................43 6.2 Accidental releases................................................................................................44 7.0 References...................................................................................................................... Page 3 of 76 GU-379 Pipeline Emergency Repair Manual Appendix-1 Appendix-2 Appendix-3 Appendix-4 Appendix 5 Appendix 6 Appendix-7 Appendix-8 Appendix-9 Appendix-10 Page 4 of 76 Mechanical methods to be used in installation of sleeves Plidco Split + Sleeve Plidco Smith + Clamp Plidco Weld + Cap Fixing arrangements for Plidco Weld + End Plidco Flange + Repair Ring Plidco Flange Repair + Split Sleeve List of Emergency Material Manufacturer Instructions User Comment Form . The manual gives practical repair and maintenance solutions to various potential emergency situations.5 of SP-1211. Page 5 of 76 . An emergency repair differs from a planned repair in that the time available for assessment of the best course of action. safety and the environment and to resume the operation without any further loss in production. bypass lines and other related on plot facilities are excluded. material supply and execution time are limited by the need for resumption of production. Repair of subsea carbon steel pipelines is briefly covered in this document. However. These latter repairs shall form part of the plant repair/shutdown manual.2 Scope This document covers the emergency repairs of off-plot pipelines. therefore. In this regard expediency is a more important factor than achieving the cheapest capital cost of the repair itself.1 Objective The objective of this manual is to provide a structured approach for emergency repairs to Carbon steel pipelines.GU-379 Pipeline Emergency Repair Manual 1. particularly as the time saved due to fast repair will lead to lower losses in production throughput of the pipeline. On plot emergency repairs including those related to scraper traps.2. It is not possible to foresee every condition that may arise in the event of a pipeline requiring repairs and. The document covers emergency repairs for internally and externally coated/lined pipelines but repairs to cathodic protection systems are excluded. 1. These procedures provide information essential to the Emergency Controller when making decisions and formulating an action plan to control and rectify a wide range of emergency situations. In the event of an emergency situation. The manual provides the user with information to select and execute a suitable repair method for a given pipeline damage scenario. The recommendations covered pertain to both aboveground and underground Carbon steel and GRP pipelines.0 Introduction 1. This document covers emergency scenarios for the off-plot portion of a pipeline outside the plant boundary. The repair methods specified in this manual can be used for repair of all classes of pipelines as defined in section 3. The main purpose of the manual is to define the guidelines and requirements for emergency repairs in order to reduce the execution time in the assessment of the emergency scenario and deciding the best course of action. GRP off-plot pipelines and subsea pipelines. The main purpose of an emergency repair is to restore the structural integrity of the pipeline in the most efficient manner. to avoid further damage to health. the emergency material is stocked for class-I pipelines only. reference shall be made to the PDO Emergency Procedures. the exact course of action to be taken must be decided upon by the engineer in charge of the repair. Injurious defect: . 1.a critical condition that may endanger life. The company may include an agent or consultant authorised to act on behalf of the company. Company . Leaking cracks: . services (including consulting services) and manpower.4. Temporary repair: .4. Permanent repair: . It also briefly covers the aspect of detection or identification of the defects by reference to the relevant DEP / Standards. May . Page 6 of 76 . which. repair or derating of the pipeline. Cracks may be found in the girth welds.The party that has a contract with the Company for providing work (including emergency repairs). environment and/or assets.indicates a requirement.0 of this document. The cracks usually occur due to excessive straining during the initial mechanical formation of the pipe or as a result of micro-structural sensitivity to certain environments.2 Specific Definitions Defect: . guidelines and procedures are indicated in section 6.is Petroleum Development of Oman LLC.3 Applicable Standards The list of applicable standards.a defect which requires removal. which are often high in hydrogen or sulphur content. Should . 1. specifications. is insufficient in extent to cause complete rupture. Emergency: . codes.a repair that makes a pipeline safe for service for a limited period of minimum 3 months. material. in combination with tensile stresses. 1. For non-leaking injurious defects. ‘Contractor’ shall be read to also include ‘sub-contractor’ and parties providing support to contractors and sub-contractors. reference is made to requisite DEP/PDO standards. The company may undertake all or part of the duties of the contractor. Shall . seam welds or in the pipe body.GU-379 Pipeline Emergency Repair Manual Only leakage emergency scenarios are covered in this manual.4 1. without any other influence. The scope of the manual is taken from the point where the leak has been identified and located.1 Definitions and Abbreviations General Definitions Contractor .Stress induced separation of the pipe material.a flaw which may have a deleterious effect on the structural integrity of the pipeline.a repair that makes a pipeline safe for continuous service for the remaining period of its design life at its maximum allowable operating pressure or at a reduced pressure. equipment.indicates a recommendation.indicates a possible course of action. certifying agencies and authorities. 1. Typical parties include operators. design consultants. inspection. construction contractors. Emergency repairs for Subsea CS pipelines 5. repair and maintenance contractors. References at the back of the manual will include relevant reference material. Introduction 2. Safety 6. inspection. design consultants.3 1. ANSI American National Standards Institute ASME American Society of Mechanical Engineers DEP Design and Engineering Practice (SHELL documents) HIC Hydrogen Induced Cracking MPI Magnetic Particle Inspection NPS Nominal Pipe Size SCC Stress Corrosion Cracking UT Ultrasonic Testing Distribution/Target Audience The document is intended for use by PDO and all other parties involved in the pipeline maintenance and emergency repairs as a basic guideline for the emergency repair of pipelines. abating the existing or probable hazard.4.6 Document Structure The document comprises of the following sections: 1. 1. construction contractors. certifying agencies and authorities.GU-379 Pipeline Emergency Repair Manual Prompt action: Consists of dispatching qualified personnel without delay for evaluating and. Page 7 of 76 . repair and maintenance contractors. procedures and planning required to meet the objectives of the manual. The document is intended for use by PDO and all other parties involved in the pipeline maintenance and emergency repairs as a basic guideline for the emergency repair of pipelines. where necessary. Typical parties include operators. References The sections will be further sub-divided to cover the relevant technical / safety considerations. Emergency repairs for Carbon steel pipelines 3.5 Abbreviations API American Petroleum Institute. Emergency repairs for GRP pipelines 4. The review authority will be CFDH Pipelines. No changes will be made without the approval of the Custodian (CFDH Pipelines).GU-379 Pipeline Emergency Repair Manual 1. Page 8 of 76 .7 Review & Improvement These Guidelines will be reviewed and updated once every three years. repair methods and the safety requirements to be followed during repair. safety. These Level I emergency defects pose an immediate threat to the health. Page 9 of 76 . environment and/or production.All leaking defects in Class I pipelines are classified as Level I emergency defects. The pipelines covered are for diameters ranging from 4” to 48”. Therefore the time available for carrying out repairs for such defects is more than the time available in Level I emergency defects. These are classified in the following two main types: Emergency defects:. no specialised procedures and resources are required. the resources required to deal with the repair and the consequences. dictated by the type of the defect. equipment.All non-leaking injurious defects as defined in SP1235 in Class I pipelines are defined as Level II emergency defects. which require immediate and prompt action and also need specialised procedures. Therefore. It excludes the repair details for other metallic pipelines e. wall thickness ranging from 4. However. but is less than the time available for nonemergency defects. The time available for carrying out repairs for such defects is more than the time available in cases of emergency defects.1 Scope This part of the document defines emergency repair requirements for carbon steel pipelines. does not have any immediate impact on the health. Level I emergency defects: .2 Types of defects and its causes The possible repair methods are. The period between reporting of a defect and the repair shall be kept as short as practicable. to a large extent. duplex material etc. inspection. 2. environment and production and therefore needs to be rectified on an immediate basis with ‘prompt action’. These defects do not pose an immediate threat to health. ductile iron.a defect which. environment and production. safety.06mm and steel grades conforming to API 5L up to Grade X-70.a defect in the pipeline that has a deleterious effect on the health.GU-379 Pipeline Emergency Repair Manual 2. The various types of defects in a pipeline system can be classified on the basis of availability of time required for repair.8mm to 20. safety. the extent of damage to the pipeline system is such that these defects can at any time become leaking defects. Such defects in a pipeline system are those. The subjects addressed in this part of the document contain information regarding assessment of an emergency defect. Emergency defects can be further categorised Level 1 and Level 2. have the potential to become emergency defects and thereof need planned repair. Non-Emergency defects: . in its present state. Level II emergency defects: . safety.g. However. environment and/or production. manpower and supplies to protect the public safety or property from an existing or potential hazard.0 Emergency Repairs for Carbon Steel Pipelines 2. such defects can if not rectified. the pressure in the pipeline system is drastically reduced and also.4 Types of Level I Emergency Defects Level I emergency defects can be further categorised based on the type of leaks into: Minor Leak A leak (also called a pinhole leak).II L e a k in g In ju r io u s D e fe c ts N o n L e a k in g In ju r io u s D e fe c ts (A s p e r S P -1 2 3 5 ) M a jo r L e a k R u p tu re P i p e M i ll D e f e c t s G i r t h W e l d D e f e c ts D e n ts C r a c k s /A r c B u r n s S p a llin g . P i p e l in e D e f e c t s E m e rg e n c y D e fe c ts M in o r L e ak N o n -E m e rg e n c y D e fe c ts L e v e l-I L e v e l . Geo-technical forces 5. where the largest dimension of the leaking hole is < 3mm. Corrosion/sensitivity to environment The most common reasons for pipeline failures are third party interference or corrosion.GU-379 Pipeline Emergency Repair Manual Such defects can be repaired in a planned manner. Third party interference 2. but must also be rectified in a timely manner to ensure that do not become emergency defects. Excessive operational loads/errors 4. In these cases. G r o o v e s G e n e r a l /L o c a l M e t a l L o s s Fig. Major Leak A leak. 1: Summary of pipeline defects 2. where the largest dimension of the leak hole is > 3mm but less than 60% of the outer diameter of the line pipe Rupture A rupture is a defect where the largest dimension of the leak hole is >60% of the outer diameter of the line pipe. the leakage rate from the defect is high. Manufacturing/construction/design/material defects 3. Page 10 of 76 .3 Causes of Emergency Defects The occurrence of emergency defects in the pipeline system can be attributed to one or a combination of the following causes: 1. G o u g e s . 2. leaks occurring from flanges/ flanged fittings.10). reference shall be made to DEP 31.60. valves etc.9 and 2.3.g. 2. Perform damage/leak assessment survey 3. Leaks occurring in pipeline systems in the vicinity of road and wadi crossings shall require different repair methods than the leaks reported from other areas. Page 11 of 76 . Smell of the fluid being transported in the leaking pipeline 5. will involve patrolling (walking. For detailed guidelines on the leak detection. Identification of suspected leaks. which cannot be explained by the analysis of the regular operating conditions. A loud whistling sound associated with a leak in a high pressure pipeline system 4. Analyse damage assessment survey and decide upon repair options 4. A drastic reduction in pressure normally indicates the presence of rupture in the pipeline and requires an immediate shut down of the system.visual observation to detect abnormal or unusual indications in vegetation. Detection of defect/leak 2. unless it has been sighted and reported by 3 rd party/ PDO surveillance team or in the absence of a suitable leak detection technique. Note: This manual places greater emphasis points 3 & 4 above.5.. Fire near a pipeline facility Other essential warnings signs of a leak include a reduction in the pressure or discharge flow rate in the pipeline system. 2. Possible shortness of breath in the area of a leak 6. Repair methods adopted for Level I emergency defects will depend on the nature of the leak and location at which the leak occurs.GU-379 Pipeline Emergency Repair Manual In addition to the above.40. an area of dead vegetation or a build up of frost on the ground 2. Mobilise emergency repair equipment/contractors and commence repair works as per procedures outlined in this manual. driving or flying) the pipeline to identify evidence of one or more of the following: 1. The extent of pressure reduction in the system is nominal in cases of major leaks whereas it may be unnoticeable for cases of minor leaks.3.11 and PR-1066 (Clause 2. shall also be considered as Level I emergency defects. Vegetation disturbances . e.1 Detection/identification of leak Timely detection/identification of leaks is essential to prevent catastrophic effects of the leak.5 Level-I Emergency Defects The events/activities related to Level I emergency defects can be categorised under following four main headings: 1. Points 1 & 2 have only been covered in brief. Visual identification of fluid spillage 3. On reaching the location of the leak. Use of hot work for the repair (may require decommissioning of the pipeline) Page 12 of 76 . For leakage survey procedures. ultrasonic leak detection tools etc. equipment and test methods for gas leakage.5. 2. Excavation for live pipelines shall be done as per ERD 38-11. minor or rupture.5. These inspection results shall be further interpreted/assessed by trained personnel to classify the leak into major.0 shall be implemented before start of digging. The probable locations of the leaks are identified in the previous phase of leak detection. In cases where the leak has been detected by inspection tools. leakage pinpointing. reference shall be made to appendix-M of ASME B 31.3 Shut down and pressure reduction Under normal circumstances. at locations of soil movement or settlement or inadequate pipe support conditions etc. leak assessment/inspection for buried pipeline is normally done by digging at the location of the leak and reaching the leak position on the pipeline. Risk of growth of the defect at locations with stresses other than those due to internal pressure only e. size and assessment of the defect/leak. In the absence of readily available inspection tools or due to the lack of time. 2.GU-379 Pipeline Emergency Repair Manual Once a suspected leak is confirmed. no digging may be required at this stage as the results produced from the inspection tests normally detail the type. no shutdown is required for cases of minor leaks as the repair can be done on a running pipeline except in cases of pipelines transporting excessively sour or hazardous fluid and passing through areas of higher location classes (class 3 and 4 as per SP-1211).g. Presence of defect (leak) in critical location 3. Suitable safety measures as detailed in Section 5. All necessary safety measures as required and specified in the later parts of this document shall be adopted during the operation. 2. This phase will also involve exposing the pipeline at probable locations of a leak to ascertain the exact location. further visual inspection shall be done to assess and categorise the damage. All loose wrapping shall be removed and the damaged area shall be cleaned of all traces of mud and extraneous matter.8-2003.4 of this manual. Shutting down or pressure reduction during minor leaks becomes essential in the following cases: 1. Excavation at the damaged portion of pipeline shall be carried out with due regard to trench stability and safe egress. Assessment and categorisation is essential in deciding on the repair procedure and safety methods to be adopted during the repair. the reason for leak and to propose the strategy to be followed in the repair of these defects.2 Defect/Leak Assessment/Inspection Once the leak has been detected and located it should be accessed and categorised in accordance with Section 2. identification of the exact location of the leak involves mobilisation of crews with leak detection equipment such as gas detectors. In cases involving hazardous major leaks. The decision for shutting down the pipeline shall be taken by the local emergency coordinator who must carefully assess the risk and consequences involved and the loss in production on account of a shutdown. to prevent any growth in the defect and to prevent any increase in threat to health. However it is essential that the operating pressure of the system be reduced for all cases of minor leaks to a maximum of 80% of the operating pressure at the time of defect reporting to ensure safe repair operations. this option is rarely used due to the time constraints. If the pipeline has been shut down. will still result in unacceptable safety situation or an environmental impact. The criteria and extent of the pressure reduction shall be verified by the engineer-in-charge. Such methods are employed to reduce the down time of the pipeline. control the risk and avoid further loss of product.5. No personnel should be allowed near the repair until the test has been completed. the pipeline system will incur a serious pressure drop in the area of the rupture resulting in excessive loss of product. although minor. it is recommended to shutdown the system to avoid any disastrous consequences during the repair works.GU-379 Pipeline Emergency Repair Manual 4. Other safety measures as detailed in the later parts of this document shall be adopted during such repairs. Repressurising should be accomplished slowly and steadily without surges to avoid vibration of the pipeline and fittings. In these situations. Specific care shall be exercised for cases of downhills of a liquid line where the required pressure reduction of more than 80% due to static head of the liquid. For down hill sections where the 80% reduction criteria could not be met due to static head.These provide temporary relief to the defects in the pipeline system but have to be removed and replaced with more permanent alternatives during a planned shutdown or as soon as practically possible. the engineer in charge shall decide the operating pressure during repair period. Note: The pressure reduction recommended above is the reduction required at the time of repair. Repairs in these cases normally require sectional replacement. The pressures at which the pipeline system shall be operated after accomplishment of repair shall be decided by the engineer-in-charge in its close out report. safety or the environment. In cases involving rupture. A temporary repair is recommended only when the loss of production caused by the time needed to execute a permanent repair is such that it justifies the cost involved in both the temporary repair and the subsequent planned permanent repair. then cut out and replace the section of pipe containing the defect. 2.4 Repair options The preferred option for a permanent repair is to completely decommission the pipeline. However. The leak. Settings of safeguarding instruments shall be adjusted to maintain the pressure reduction during repair period. shutting down the system should be carried out immediately to avoid further damage. repressurising for testing after the repair should be done with extreme caution. Page 13 of 76 . The preferred repair options for Level I emergency defects can be classified into: Temporary repair options: . 6. Please Refer Section 2.CS pipelines Type of defect Minor leak Temporary repair option Permanent repair option Plidco Smith+Clamp. The length of split sleeve shall be suitable for the length of crack. Table . enabling the normal operating pressure of the system to be maintained for the remaining design life. A temporary repair should be replaced with a permanent repair method within a period of 3 months (as per SP 1210). The welded split sleeve cannot be considered as a permanent repair due to possible propagation of crack during the service.3.6 Leaks in wadi crossings Note: Plidco brand repair materials are indicated in the table for reference purpose only. .GU-379 Pipeline Emergency Repair Manual Permanent repair options: .1: Selection of emergency repair options . All Plidco equivalent PDO approved brand repair materials can also be used for emergency repair. Any further extension beyond 3 months shall be subject to demonstration of performance with confidence and written approval from competent authority (CFDH pipelines). * ** *** **** Page 14 of 76 Sectional replacement can also be achieved using Plidco weld+end couplings. Once the defect has been categorised and located the following repair options are recommended depending upon the type of defect. Not applicable for valve flanges Composite repair can be used with in the limits of qualification in accordance to ASME Code. (Refer Table 1).5. Refer to details given below in Section 2.8.These provide permanent relief to the defects.5. Plidco Split + Sleeve or similar Composite Repair**** Plidco Smith+Clamp+ Plidco Weld+Cap Plidco Split + Sleeve (duly welded) or similar Sectional replacement* Composite Repair**** Major leak Plidco Split + Sleeve or similar Plidco Split + Sleeve (duly Composite Repair**** welded) or similar Sectional replacement Composite Repair**** Leaking cracks Plidco Split+Sleeve** or similar Sectional replacement Rupture NIL Sectional replacement Leakage through flange Plidco Flange + Repair-Ring Sectional replacement Plidco Flange-Repair + SplitSleeve*** or similar Leakage through valve Nil Valve replacement/repair as per manufacturer’s recommendation Leaks in road crossings See Section 2. 5. Page 15 of 76 .5. The temporarily repaired sections of these internal PE lined pipelines shall be replaced by a permanent alternative method within 3 months period as per section 2. shall be laid using thrust/auger boring.4. This is more critical in areas of road crossings. on a major road. Temporary repairs are short term and will ultimately have to be replaced with more permanent repairs which will require further closure of the road for open cutting.GU-379 Pipeline Emergency Repair Manual 2.6 Repair options for leaks at areas of road and wadi crossings The repair options specified in Section 2. The sectional pipe shall be joined to the main line using Pildco Weld + End Couplings or welding as shown in Figure-2 . along with the sectional spool piece.g. The flange-to-flange sectional replacement including replacement of damaged liner is the only recommended permanent method of repair for PE lined pipelines. The leaks in these lines shall be temporarily repaired using Plidco split sleeves or mechanical clamp in an emergency situation. 2.5. Temporary repair options for leaks in these areas are not recommended due to the following associated disadvantages:1. For roads where open cut is not possible. The temporary repair options do not enable the complete structural integrity of the pipeline to be restored. the repair works shall be done using boring/drilling to avoid disrupting the traffic movement. e. In such cases a casing pipe. 2.5.g.3 of SP-1210.4 are applicable for pipeline leaks at road crossings subject to the condition that open cut repair is feasible for such roads. traffic diversion during the repair works should not lead to any major disruption. e.5 Repair of internal PE lined pipelines The PE lined pipelines may develop leaks either due to 3 rd party interference to such an extent that the liner is also damaged or in-service failure of liner and subsequent corrosion of the pipeline. normal methods as described in Section 2. in case if continuous oozing of water is noticed. Following diversion. arrangements should be made to divert the wadi stream and evacuation of remaining water in wadi prior to starting the repair activity. if the wadi does not contain water.4 can be used to carry out repairs. Temporary repair options are not recommended for leaks in wadi crossings. Page 16 of 76 . In case if the pipeline leak occurs in a live wadi (for example during rainy season). Continuous evacuation of water using vacuum trucks might be required during repair activity.GU-379 Pipeline Emergency Repair Manual Figure 2: Sectional replacement of defective pipeline at road crossings Leaks in pipelines at wadi crossings are more critical as the leaking oil/gas is likely to spread to a larger area through the flood water (during rainy seasons). The concrete coating shall be done in such a way that the sleeves do not get damaged due to presence of gabions over them. After completion of the repair works. the repair shall be similar to that of dry wadi region explained above. During non-rainy seasons. the complete sectional spool along with the associated sleeves shall be recoated with concrete in-situ. the concrete coating over the pipeline shall be removed and the necessary repair carried out. evacuation of wadi.5. For wadi types B and C. blow out can be prevented during welding provided the minimum thickness is not less than 4. pipe thickness. UT inspection etc. The cleaning shall achieve removal of scale. Before assembling the repair fittings to line pipe an ultrasonic inspection shall be conducted to cover a zone extending a minimum of 100mm on the either side of each weld area to confirm a minimum wall thickness (refer point no.8. coatings and vegetation by the use of wire brushes. based on either specific previous experience and/or data from trials.8mm (reference shall be made to Appendix-2 and 3 of DEP 31.C with a hoop stress not greater than 72% of the specified minimum yield stress. The grit blasting shall be permitted only when remaining wall thickness of the pipe is more than 2 mm.5. 1 above.7 Repair activity procedures The activities detailed below shall form part of the overall repair works and shall be applied in conjunction with the procedure for carrying out the specific repairs detailed in Section 2. .5. it shall be ensured that during the welding operation the material in the region of the weld pool has sufficient strength to contain safely the internal pressure and avoid a blow out. Reference shall be made to SP-1246 for this purpose.7.38.1 Procedure for cleaning of the defect area The surface of the defective area of the pipeline shall be cleaned to enable repair.all reflectors exceeding 100% DAC shall be cause for rejection.10). 2 below) and to check for the laminations. Page 17 of 76 . Ultrasonic test techniques shall be in accordance with ASME V article 5 as supplemented by SP-1176.60. Levels of indications requiring investigations are as follows:. pipe material. pipe temperature and hoop stress.all reflectors giving an indication in excess of 20% DAC shall be investigated and evaluated in accordance with the acceptance standard (DAC = Distance Amplitude Correction). 2. The actual minimum wall thickness shall be determined by ultrasonic testing as specified in point no. operating at temperatures of not greater than 350 deg. Before carrying out any kind of weld repair on a live pipeline. The risk of blow out is dependent upon a complex interaction of welding conditions.all reflectors giving an indication in excess of 50% DAC shall be evaluated and reported.2 Confirmation of suitability of live pipeline for permanent repair welding The following checks shall be done to confirm the suitability of the live pipeline for the purpose of welding:1.5. For other materials or conditions.7. . 2.GU-379 Pipeline Emergency Repair Manual 2. Laminar defects exceeding 6mm in any direction and any lamination not parallel to the pipe surface shall be unacceptable. For material of yield strength not greater than 448 MPa (Grade X-65 as per API 5L). a minimum pipe thickness shall be determined. rust.5. 2. chipping tools or grit blasting. welding. clamps shall be done as per SP-1167 and DEP 31. The maximum allowable operating pressure during welding shall be determined as per Clause 3.3 of DEP 31. Under these circumstances the minimum inter pass temperatures may not be attainable.7mm. Welding on live pipelines is prohibited for the following cases:.3. which are susceptible to cracking. the effect of flow on both weld cooling rates and burn through are less significant. . It is also essential to prevent any propagation of any unstable cracks. Page 18 of 76 .For wall thickness between 6. Reference shall be made to Clause 3. Note:. nitrogen purging (de-commissioning) shall be done using a minimum purge velocity of 0. There is no restriction on maximum velocity for gas lines. Minimizing the flow rate reduces the risk of cracking and of burn through.GU-379 Pipeline Emergency Repair Manual 3. For metal thickness greater than 12. subject to the attainment of acceptable inter pass temperatures.10 and selected approved welding procedure. Attention shall be paid to controlling the pipe wall temperature during the welding to avoid deterioration of the microstructure of the pipe material due to excessive heat input resulting in excessive metal temperature. Welding on a live pipeline under no-flow or intermittent flow conditions shall not be attempted unless it has been confirmed that no explosive or flammable mixture will develop during welding operations.No welding shall be performed on lined. The size of the fillet weld should be at least 1.10.2 of DEP 31.3.60. A high liquid flow usually causes rapid cooling of the weld area which results in hard material zones.Oxygen enriched atmospheres in the presence of hydrocarbons which may be present either in the atmosphere or in the deposits on the inside surface of the pipe.38.3 Procedure for welding/inspection for emergency defect rectification All emergency repair welding and inspection of welds on pressurised pipeline systems. This shall be based on the derated pressure conditions necessary whilst the material is at elevated temperature whilst welding.60.60. In cases where this requirement cannot be met. 5. 6.4mm and 12.5.38. including the welding of sleeves. clad or internally coated pipes 4. .75m/s. Careful control of the size and shape of the circumferential fillet welds. resulting in undesired material properties.7mm.38.4 times the wall thickness of the pipe at the weld area. flow also increases the weld cooling rate and hence the risk of cracking. 7. 2. The pressure in the pipeline system shall be verified to confirm that it does not exceed the maximum allowable operating pressure during welding operations.Mixtures of gases or vapours within their flammable range or which may become flammable as a result of heat input in welding operations.7.4m/s. Other precautions needed during welding include:1. In this respect it shall be confirmed that no ingress of oxygen in the line is possible. A suggested maximum velocity for liquid flow during welding is 1.10. the greater the resistance to fatigue failure. 6. in some scenarios. the defective line pipe shall be assumed to be API 5L Grade B. which shall be used for the new replacement pipe if no material specification records are available.GU-379 Pipeline Emergency Repair Manual 2. First weld pass for pipelines with a wall thickness less than 6. to monitor heat generated during welding or preheating operations. 4.4mm thick should be achieved by using 2. For pipelines with wall thickness more than 12. 100% radiography. UT and MPI shall be done on all emergency repair welds.4 Procedure for recoating/painting of the defect area After completion of the repairs. Welding conditions and relevant parameters shall be noted and test pieces shall be prepared once the job is complete. Page 19 of 76 . 8. If the heat generated approaches the temperature limit of the seal material. The pipeline engineer shall decide the WPS and PQR to be followed in consultation with repair contractor and welding engineer. The smoother and more streamlined the weld profile. 5.7mm.4mm or smaller diameter welding electrode to limit heat input. to determine if the method meets the requirements of the application.5. However. 7. Avoiding burn through during the root run. If no records are available. welding should be discontinued to allow the affected area to cool. If deemed necessary. particularly near the areas of the soft seals. 2. 3. Maintenance of a concave faced fillet weld with streamlined blending into both members. Avoiding notches and undercuts during welding. 3. Ensuring that welding does not overheat the seals. in order to carry out weld repairs without the delay the following deviations are permitted from SP-1177:1. It may be necessary to re-torque the stud bolts and nuts periodically during field welding because weld contraction causes them to loosen. 4. the defective area shall be recoated / repainted as per SP-1246. The welding should be sequenced so that the heat is not concentrated in one area. All records and test piece results shall be reviewed after the repair. Use of welding consumables as indicated in approved WPS. where burn through is not a primary concern. Use of temperature crayons or probe thermometers. SP-1177) shall be used for welding on live pipelines to avoid delay due to pre-qualification. cutting out and replacement of unacceptable weld repairs shall be planned and executed as per SP-1177. care should be taken by avoiding the use of excessive welding current.7. 2. which is indicated on the label. PDO pre-qualified welding procedures and welders (PR-1276. 2. most of the fluid is drained from the pipeline during the depressurisation process by shutting down the flow and opening the valves at the receiving end station. After completion of the initial backfill layer. isolation and draining/venting of the pipeline for defect repair Venting/Draining of the pipeline Complete draining and venting of the pipeline is essential in cases of sectional replacement of a defective portion of the pipeline.5 Procedure for sand padding and backfilling of the trench 1. For pipelines without block valve stations: For such pipelines.7. The minimum depth of padding below the pipe shall be 300 mm. Screened soft sand. Where the excavation crosses wadis or ditches with lined or otherwise improved surfaces. Windrow shall be reinstated. Reference should also be made to ERD 38-11 and SP-1208 for details on reinstatement. the entire length of the pipeline shall be drained. For any residual Page 20 of 76 . Where there are no block valves. For pipelines with block valve stations draining can be limited to the section between the block valves. The depth of the sand padding over the top of the pipe shall be at least 300 mm. 6. these shall be reinstated to their original contour and condition. The remaining fluid can be drained by opening the drain and vent valves at each end.GU-379 Pipeline Emergency Repair Manual 2. Hand shovel and wooden hand-ramming device shall be used for the placement of sand under the pipe.0 metre - Compacted ground: distance from battered edge of trench shall be 1. 4.5.6 Procedure for de-commissioning. The mechanical excavator shall maintain the following minimum safe distances (which shall be clearly marked by a line of bunting) from the edge of the trench: - Rock: distance from edge of trench shall be 1. Sand on top of the pipe shall be shaped to the natural angle of repose. In order not to damage the sand padding. The drained fluid shall be disposed of safely to prevent any hazard to life or the environment. free of rock and foreign matter. 2. the initial layers of final fill shall be carefully lowered into the trench from each side by mechanical shovel ensuring that the backfill material is deposited carefully to avoid disturbing the sand padding. 3. 5. the remaining backfill shall be finished to a level slightly above the natural grade and shall be thoroughly compacted by means of a compacting vibrator. Screened excavated material from the location shall be used (after the removal of any rock and boulders) on top of the sand.5 metre - Soft sand with trench sides battered to a minimum slope of 2:1: distance shall be 2 metres. including the section used for temporary crossings. 7. Sand shall be lowered into the trench with a mechanical shovel and hand spread uniformly around the pipe. shall be used for sand padding.5.7. Note: It is also feasible to drain and vent the pipeline by installing a hot tap through which the pipeline contents can be drained. mud/freeze plugs or Hi friction pigs is recommended. the ruptured or leaking portion of the pipeline shall be covered temporarily either by a sleeve or composite reinforcing sleeve and pigging with soft pigs carried out. vented or flared. 2. controlled venting can be done to atmosphere through the vents provided at the BV stations. The use of suction pumps is limited depending upon the capacity of the pump available and the length/terrain of the pipeline and is only recommended for small lengths. This shall be done as follows:1. further localised isolation by use of specific pipeline isolation plugs such as PE Grip Lock Pipe Plugs. air plugs. Page 21 of 76 . This can be accomplished as follows:1. Any remaining liquid can be removed using suction pumps. to displace the remaining liquid. Venting of any hazardous gases shall only be allowed only through the designated vents and shall be suitably flared in accordance with standard safety procedures. Another method of draining the liquid line is by flushing with water (for general details refer to PR1074) 2. For gas pipelines. For liquid lines. Alternatively. The suction hose shall be inserted into the pipeline either through drain valves or through the leaking portion and the liquid transferred to a tanker. any remaining trapped gas can be vented by purging with inert gas from one or both ends of the pipeline. For the handling non-sour gases. the engineer-incharge shall study the need for further draining/venting. the trapped liquid shall be drained out through the drain valves at the block valve stations. The capacity of the suction pump should be sufficient to drain approximately 32 km of pipeline – being the maximum length between two block valve stations. Venting of any hazardous gases shall only be allowed through designated vents and shall be flared in accordance with standard safety procedures either through temporary mobile flare or as directed by the PDO Safety Officer. For liquid lines. The suction hose shall be connected to the drain lines at the block valve stations. Isolation of the pipeline If deemed necessary. driven with compressed nitrogen or water. Any remaining trapped gas can be vented out by inert gas purging from one or both stations. even after isolating and draining the defective section at the block valve stations. Flushing with water can also be undertaken to remove the hydrocarbon liquid as specified above. the trapped liquid can be removed using suction pumps. For pipelines with block valve stations: For these pipelines.GU-379 Pipeline Emergency Repair Manual fluid trapped in the pipeline such as in areas of lower elevations. only the portion between the block valves needs to be drained and vented. wall thickness. This report shall be in addition to any other requirements specified in the PDO emergency procedures and HSE 97-01/PR-1060. The requirement of isolation for these pipelines shall be verified by Operations personnel and done in accordance with PR-1076. The recommended table of contents shall be as follows:1.Hot tapping the line to provide a means of inserting the plugs/stopples to isolate the defective line section may affect a safe repair. environment and loss of production) 3.7. As built drawings revisions. operating pressure. Any other additional checks or tests found necessary to verify the integrity of the pipeline. Page 22 of 76 . 5. cause and assessment of damage (safety.GU-379 Pipeline Emergency Repair Manual For smaller lengths where no block valve stations exist. including the requirement to derate the pipeline after completion of repair if necessary. 2. Pipeline service and details (fluid transported. 6. flow. Isolation of a defective portion of a pipeline without block valves is essential to prevent the possibility of trapped fluid draining from other areas whilst repairs are in progress and also to prevent transfer of welding fumes to other segments of the pipeline.7 Emergency repair close out report The purpose of the close out report is to capture all the relevant actions taken to identify the cause of damage.5. Considerations should be given to the factors such as product characteristics.) 2. the pipeline shall be first decommissioned and then the defective segment is isolated using air/mechanical plugs/stopples. Repair method (advantages and disadvantages) 4. diameter. the repair methods used and to serve as feedback to correct any deficiency and make future improvements. Conclusions and lateral recommendations. Feedback to pipeline emergency repair manual. pipe condition. temperatures and required differential pressures to ensure that the proper type of plugs are used and that their holding capacity can adequately resist the pressure to be encountered. Various types of plugs that can be possibly used for isolation include mud plugs. 7. Type of defect. year built etc. Note:. freeze plugs and mechanical/air plugs. Weld the Cap and inspect the weld as per Section 2. Welding of the Weld + Cap is required for permanent repair 5.2 Plidco Split + Sleeve These can be used for temporary and permanent repairs.5.1 Install Plidco Smith + Clamp as per manufacturer’s procedure Prepare detailed report as per Section 2.1 Plidco Smith + Clamp + Weld + Cap Plidco Smith + Clamp is a temporary repair solution for minor leaks. Prepare detailed report as per Section 2. For ease of reference the Plidco Smith brand of repair materials have been quoted in this manual. Plidco Weld + Cap are available in standard sizes from 4” to 48” 4.5.3 Ensure all safety precautions as per Section 5.5. Install Plidco Weld + Cap as per manufacturer’s procedure 8.7.4 10.GU-379 Pipeline Emergency Repair Manual 2. The standard pressure rating for Plidco Smith + Clamp and Plidco Weld + Cap is 2000 psig (~138 barg). Sand padding and backfilling as per Section 2.5” to 48” 2.8. Verify the pipeline as per Section 2.7. 2. The draw bolts at the bottom of the fitting are used to hold the clamp in place.5.0 Clean the defect area as per Section 2. The point of the cone is centred exactly on the hole.7. 2.5. Can tolerate only minor surface irregularities up to + 1/32” Procedure for installation on live pipelines: For temporary repair: 1.2 7. equivalent products available from other manufacturers can also be used provided they are an approved vendor listed in the AVME.8. Recoat/paint the system as per Section 2. The use of a welded Plidco Weld + Cap when used in conjunction with the Plidco Smith + Clamp makes the repair permanent. Reference shall be made to Appendix 3 and 4 for details. The seal welded Plidco Split + Sleeve is considered as permanent repair solution.8 Emergency repair methods – CS pipelines The following sections cover the various emergency repair methods for CS pipelines.7.5. Page 23 of 76 . Verify and confirm the suitability of the pipeline for welding as per Section 2. 4.5.7. However. Plidco Smith + Clamps are available in standard sizes from 1. and force applied using the force screw to shut off the leak.7.3.5. Applications : 1. 3. 3.5.5.7 2. 5.5 11.5.7 For permanent repair continue as follows: 6. 9.7. 2. 6. Other materials are available on request.5. Standard Plidco split + sleeves are available for a working pressure up to 1000 psig (~ 69 barg). The sleeve thickness shall be adequately increased to compensate for the groove of the backing strips or seams of the pipeline. A 516 or equivalent.5” to 48” 3.5. The seal can tolerate only minor surface irregularities up to +1/32” 7. They shall be covered with dark polyethylene to protect the material from direct sunlight. 2.GU-379 Pipeline Emergency Repair Manual Note: It is preferable only to use this system as a temporary repair method because of the high cost. Standard body materials are A 106 seamless pipe.7 For permanent repair continue as follows: 6. These shall be welded to the original sleeve using qualified welding procedures. Procedure for installation on live line: For temporary repair: 1. Verify and confirm the suitability of the pipeline for welding as per Section 2. The sleeve shall not be used to couple pipes without sufficient end restraint because it does not provide any longitudinal restraint in an unwelded condition. cables or lift truck forks which can result in the seals being dislocated from the groove. The length of sleeve shall not be less than 0. 3. The size of the sleeve to be used shall be selected based on the diameter of the line pipe and the length of the defect. Higher working pressure or longer length sleeves can be made to order 4.7. The length shall be such that the sleeve extends a minimum of 0. Adjacent sleeves shall not be placed closer than one-half pipe diameter from each other. Over sleeves can be used to cover defects in area`s adjacent to or between the sleeves.F (49 deg C). Storage temperatures should not exceed 120 deg.7. 5. It is recommended not to weld the clamp to the pipeline and to replace it as soon as practicable with a permanent repair such as sectional replacement of the defective section.5 times the design working pressure.1m beyond the defect. The sleeves can be field tested up to 1. The seals and girder rings on the sleeve can be damaged by careless handling with lifting devices such as chains. Available in API pipe sizes from 1.1 Install Plidco Split + Sleeve as per manufacturer’s procedure Prepare detailed report as per Section 2. 5. 4. The sleeve should be stored in a dry environment to prevent the unpainted surfaces from rusting. Verify the pipeline as per Section 2.0 Clean the defect area as per Section 2. Applications: 1. Reference shall be made to Appendix-2 for details.5. A 216 WCC cast steel.3 Ensure all safety precautions as per Section 5. Improperly stored units can cause the seal material to become brittle and cracked and thus lose the sealing properties.5.2 Page 24 of 76 . 8. The minimum required wall thickness and steel grade of the sleeve shall be based on the wall thickness and design factor applied to the pipeline. 9.1m.7. it is helpful to grind a pilot bevel with a generous taper on the pipe. Sand padding and backfilling as per Section 2.3 Spool Piece with Plidco Weld + End couplings The installation of a spool piece using Plidco Weld + End couplings requires shutdown and depressurisation of the pipeline. Reference shall be made to Appendix 5 for details.5. A-285. This should eliminate the risk of damage to the seals Page 25 of 76 . Recoat/paint the system as per Section 2.5 11.8 as appropriate. 11. 10. Plidco Clamp + Ring should be considered. sides and bottom of nuts as per Section 2.8. Application: 1.7. Pipelines with wall thicknesses less than those specified in the table will not withstand the force of the clamp screws and hence this application will be unsuitable. A-105. This may require additional time because liquid flow through the pipeline will have to be recommenced and safe conditions reached to permit welding. As a solution. The use of these coupling on elbows and bends is limited due to the possibility of pullouts caused by external and internal forces. ground movement etc.GU-379 Pipeline Emergency Repair Manual 7. 4. 9. Prepare detailed report as per Section 2. For badly misaligned or out of round pipe. Couplings are suitable for the minimum pipe wall thicknesses as specified in Table 2.5. A-516. 8.7. 3.5.3 8. 2. Where significant longitudinal loads are present and it is not feasible to weld the coupling. The model of the coupling must be selected to the same pressure/ temperature rating as the line pipe. 6.5. Permanent repair is achieved by welding the coupling to the line pipe. Standard sizes are available from 1. additional rows of clamping screws can be provided or the Pildco clamp + Ring may be used. Seal weld the ends. Welding on a line under no-flow or intermittent flow conditions shall not be attempted unless it can be positively established that no explosive or flammable mixture will develop during the welding operation. 9. Plidco weld+end couplings cannot sustain external forces such as temperature expansion and contraction.7. Welding in cases of unequal wall thicknesses shall be done as per ASME B 31.4 10.7. Inspect the weld as per Section 2.5. Couplings are suitable for anchored pipeline joints only.4 or 31. Temporary repair for a period of not more than 6 months can be achieved by clamping and tightening the thrust screws without welding the coupling. Standard materials are A-106. This method of repair requires shutdown and depressurisation of the pipeline to remove the defective section with complete draining and isolation of the product from the affected area. 12.7. 5.7 2. It is a time consuming permanent process as compared to other methods of repair as it requires dismantling and replacement of the affected piece of the line pipe.5” to 48” 7. The material shall conform to API 5L specification.5.3. The thickness and material grade of the spool piece shall be the same as that of the line pipe and shall be determined using the equations and safety factors as given in SP-1211. Select the spool piece of wall thickness and grade as specified above.6 5. 7.7.5.7. it is recommended that either the coupling be welded or use of Plidco Clamp + Ring along with Plidco Weld + End is recommended Page 26 of 76 . Ensure that the isolated section has been adequately drained and is free from any trapped fluid as per Section 2.1 8.3 15. Inspect the weld as per Section 2. underwater currents. Hydro-test the spool piece separately as per SP-1211 8.5. Cold cut the defective portion of the pipeline as per general guidelines given in PR-1146 10.GU-379 Pipeline Emergency Repair Manual while installing the coupling over the end of the pipe. isolate the defective section as per Section 2.7.0 7. continue as follows: 13. Prepare detailed report as per Section 2.7 For permanent repair.0 3.5. wall thickness ( mm) 6.5.5 18.5.7.1 12. Nominal pipe size (inch) 4 6 8 10 12 14 16 & larger Min.5.5.6 4.7. Recoat/paint the system as per Section 2.5.7.7. Ensure all safety precautions are in place as per Section 5.2 14.7.5. Refer to Appendix 5 for details. verify and confirm the suitability of the pipeline for welding as per Section 2.2 9. Clean the defect area as per Section 2.7. If required. Install Plidco Weld + End coupling as per manufacturer’s recommendation 11. If any of these additional forces are expected to occur. Prepare detailed report as per Section 2. Seal weld the coupling as per Section 2. Depressurise the complete pipeline system to atmospheric pressure by opening the necessary drain/vent valves as per Section 2. Sand padding and backfilling as per Section 2.5.3 10. ground movement or combination thereof.4 11. Re-commission the system. Slide the spool piece in the coupling and tighten the screws 12.7 Note : Pildco Weld + End couplings only takes into account the forces on a joint due to the internal pressure and does not consider additional external forces like thermal expansion and contraction.5.7 Table 2: Minimum pipe wall thicknesses for Plidco Weld + End couplings Procedure for installation: For temporary repair: 1.4 17.3 16.1 9.7.6 6. Shutdown the pipeline system 2.7. 7. It is a temporary method of repair. 9.5.7 Plidco Flange-Repair + Split-Sleeve The Plidco Flange Repair +Split Sleeve fully encapsulates the mated flanges and seals to the pipe beyond the weld of the flanges. 4.3 Ensure all safety precautions are in place as per Section 5.5. 7. 4. Procedure: 1. Limitations: 1.5.5.5. Bolt leakage is stopped by injecting a recommended sealant with a pressure gun. 6.1 Install Plidco Flange + Repair Ring as per manufacturer’s procedure Seal the bolts using sealant and pressure gun as per manufacturer’s procedure Inspect the system visually Recoat/repaint the area as per Section 2.5. 6.5. 8.4 Place sand padding and backfill as per Section 2. It is only a temporary method of repair.0 Clean the defect area of the leaking flange as per Section 2.7. Verify the pipeline as per Section 2. 2. Reference shall be made to Appendix-6 for details.4 Plidco Flange + Repair-Ring These are useful for stopping leaks through the gaskets of the flanges. 6.4 Place sand padding and backfill as per Section 2. High cost.8. 3. 5.5. Available for standard flange sizes ½” to 12” 150 lb to 600 lb Sealant injection required to stop leakage through the bolts. They are useful for stopping leaks through any portion of the flanges. 3. 7.7.7.5. 4.3 Ensure all safety precautions are in place as per Section 5. 5. 2. Can be used to stop the leakage through the gasket portion of the flanges only.5.5.5 Prepare detailed report as per Section 2.7. 8. Procedure: 1. 2. 2.7.5 Prepare detailed report as per Section 2.7.1 Install Plidco Flange Repair + Split Sleeve as per manufacturer’s procedure Inspect the system visually Recoat/repaint the area as per Section 2. Pressure gun required to inject sealant Cannot be used to couple the flanges and provides no longitudinal restraint. 2. 5.5 Verify the pipeline as per Section 2. Reference shall be made to Appendix 7 for details.7.7 Page 27 of 76 .8. 3. Plidco Flange + Repair Rings are installed by placing the two halves around the flange and using studs and nuts to draw them together. Application/Limitations: 1.5.GU-379 Pipeline Emergency Repair Manual 2.0 Clean the defect area of the leaking flange as per Section 2. Procedure: 1. However.6 4.38.60. 2. verify and confirm if de-rating of the pipeline is required. Re-commission the pipeline as per requirements of SP-1211. Application: 1.0 3.GU-379 Pipeline Emergency Repair Manual 2.5. Hydro-test the spool piece separately as per SP-1211. Clean the defect area as per Section 2.40.7.7 Sectional Replacement (without couplings) Sectional replacement is a permanent method of repair. The method requires end preparation of the existing pipeline for welding. Clean the cut ends of the pipeline to be welded and prepare/bevel the ends 9. Shutdown the pipeline system and transfer the product at the block valve or end stations 2. It can also be used for installing a temporary bypass to the main line to carry out a sectional replacement. Weld the replacement section with the existing pipeline as per SP-1177 10. 3. the wall thickness where the pipe is to be joined is suitable for end preparation and welding. 8. The length of the pipe to be cut out shall be such that in addition to replacing the defective section. Recoat/repaint the system as per Section 2. All requirements as specified in DEP 31.4 12.40.5. 6. Cold cut the defective section to be replaced. Inspect the weld as per SP-1177 11. Isolate and de-commission the section to be replaced to make the section free from hydrocarbons as per Section 2.8. The replacement pipe section shall have strength of at least that of the pipeline and shall meet the requirements of API 5L . The length of the replacement section shall not be less than half the diameter of the pipeline or 300mm.7.5. The properties of the original pipeline need to be known to determine the properties of the replacement pipe material to be used.38-PDO prior to installation. Page 28 of 76 . 5. A hot tap fitting is installed around the defective segment and the defective segment is removed in the same way as removing a segment from the pipe wall for branch connections using the hot tap method. 2.8. This method is a time consuming process of repair due to requiring shutdown and de-commissioning of the pipeline.5.1 7. Ensure all safety precautions are in place as per Section 5. whichever is greater. The section shall be designed as per SP-1211 with same factor of safety as used for the original pipeline and shall be hydro tested as per SP1211 and DEP 31. this requires depressurisation of the pipeline and shutdown of the system.7.10 shall apply whilst carrying out the hot tapping.6 Hot Tapping This method is used to rectify a defect in a pipeline in service. Place sand padding and backfill as per SP-1208 13. Select a spool piece of the required wall thickness and grade as specified above.5. No section shall be installed closer than 150mm to an existing weld. the availability of the personnel with the necessary skills. The composite repair is most suitable where clamp/sleeves cannot be installed due to geometric constraint e. 2.g.7. For straight pipe sections this method can be used.5. For each repair situation a risk assessment shall be carried out. reducers. T-pieces etc.6 Composite Repair: An Alternative Repair Method Composite repair method is an upcoming technology for repair of corrosion and through wall defects in a pipeline. explosion. collision and environmental loading. 2. in case suitable clamp/ sleeves are not available at the time of leak. Temperature and relative humidity measuring equipments Measuring tape. qualified and applied in accordance with the ASME code “ Non Metallic Composite Repair Systems for Pipelines and Pipe work: High Risk Applications ” with in the limits of the qualification. the availability of design data. 7.7 2. pipe marker (pen) Bevelling Machine Winches Grinders Solvent cleaner. vinyl ester or epoxy matrix. The composite material considered within the document. which can range from less than 2 years up to anticipated service life of the system. 3. 5. using simple hand tools without any welding. The risk assessment shall include consideration of the hazards associated with the system service. the ease with which it is practicable to execute surface preparation operations. The composite repair shall be designed in such a manner that it takes into account the future growth of the defect for the remaining design life of the pipeline. The ASME draft requires a repair lifetime to be specified. if designed. inspectability. are those with glass (GRP) or carbon (CFRP) reinforcement in a polyester. In addition the following tools and consumables shall be carried: 1. Leak before break. dust mask) Any additional tools/ equipment required shall be advised by the engineer-in-charge. sliding gauge.9 Minimum recommended tools and equipment The repair crews shall be equipped with all suitable equipment as required for the specific type / manufacture of the pipeline being repaired and shall carry an adequate range of fully compatible spare pipe and fittings.GU-379 Pipeline Emergency Repair Manual 14. 6. bends. 4. cleaning rags PPE (gloves. A major advantage of the method is the relative ease of application.5. The ASME article is currently in review. eye protection. These repairs can be used as an alternative to the use of Mechanical Clamp or Plidco Split Sleeve for a leaking defect (through wall defects). and performance under upset and major incident situations including fire. Page 29 of 76 . Prepare detailed report as per Section 2. The key point that must be considered in design and application of bonded repair is that the combination of pipe material/ surface preparation technique/ composite is the basic design unit. Surface preparation activity involves removal of loose debris and corrosion products followed by mechanical abrasion.8 Repair organisation The repair organisation and contingency plans for PDO pipelines are given in the Emergency Response Document. it is necessary to plug the leak on-line or depressurize the line.2. PR-1068 Volume-14. laminate lay up etc. 2. installer qualifications. PR-1066 .10 Gas Pipeline Failure Volume-4. To achieve the required dry surface.Clause 2. Part-III in the following volumes:Volume-3. all necessary safety precautions should be followed as per PDO procedures.3. PR-1246 Volume-15. Production Operations. Data derived using one set of material cannot be used to assist in the design of another even if it is only one of the components comprising the arrangement that has changed. Repair shall be carried out in accordance with the manufacturer’s procedures and by manufacturer approved and trained personnel. Reference is made to SP-1235 for possible repair options and methods for level-II emergency defects.GU-379 Pipeline Emergency Repair Manual Manufacturer of composite repair material should provide full installation instructions including surface preparation. Government Gas System Pipeline & Terminals. The second important aspect of repair is surface preparation.3. For surface preparation using grit-blasting technique on live lines. The limitations of this method are that it needs a dry and mechanically clean surface for achieving a durable bonded connection between pipe and laminate. quality of surface preparation should be in conformity with SA 2 ½.7 Level II Emergency Defects. grit blasting.Clause 2. Terminal & Tank Farm Operations. They have a nominal impact on the productivity of the pipeline due to the requirement for pressure reduction.9 Oil Pipeline Failure . 2. Main Oil Line PR-1067 Volume-5. South Oman Gas Line PR-1275 Page 30 of 76 . Normally.Injurious non leaking defects These defects are as described in section 2. 4 1 Third party interference (the most common reason) 2 Excessive operational loads/upset conditions (refer Section 3. 3. Further quality checks are made by carrying out visual inspection and pressure testing prior to commissioning of the system. ISO 14692 (part 1 to 4) and DEP 31. The emergency repairs for other non-metallic pipelines including HDPE systems are excluded from the scope. Page 31 of 76 . Most of the GRP pipelines are of buried type. which may be catastrophic in nature.1 General GRP pipelines for PDO have been constructed after satisfactory and rigorous qualification tests have been carried out on the GRP systems. This manual identifies the possible catastrophic defects. installation. 3. The defects considered are those that could be encountered during the operation of the GRP pipelines. GRP pipeline systems can suffer operational defects. “GRP Pipelines and Piping Systems (Amendments/Supplements to ISO 14692)” form the basis for this document. it is advised to replace the complete line or else fitness for purpose evaluation shall be carried out as per manufacturer’s recommendation.40. 3.5 Defect categorisation The defect categorisation of GRP Class-I pipelines is similar to that of CS pipelines specified in Section 2 of this document. testing and commissioning stages are excluded from this manual. If any such situation occurs.2 Scope This part of the document defines the emergency defects and the repair respective requirements for GRP pipelines. 3.10. Defects detected during the manufacturing.3 Causes of defects in an operating GRP pipeline system The occurrence of defects in an operating GRP pipeline system can normally be attributed to either one or a combination of the following. categorised as emergency defects. with the exception that weeping defects are included in Level-1 emergency defects.4 below) Defects due to over pressurisation The over pressurisation of a GRP pipeline system due to failure of the over pressure protection systems or excessive surge beyond design limits normally leads to weepage or rupture of the pipeline.0 Emergency Repairs for Glass Reinforced Plastic (GRP) Pipelines 3. and specifies the appropriate repair methods.19.GU-379 Pipeline Emergency Repair Manual 3. 3. In weeping there is no apparent visual indication of a defect in the GRP material and mainly occurs due to disturbance in the fibre matrix. steadily increasing the pressure without surges. Page 32 of 76 . re-pressurisation should be done with extreme caution. It mainly constitutes seepage. The repair options for GRP pipelines are normally the replacement of the defective section and therefore. Sectional replacement.GU-379 Pipeline Emergency Repair Manual Weeping defects : . In case. shutdown.6 Repair of Level-I Emergency Defects The leak detection. which could vibrate the pipeline and the associated fittings leading to integrity problems. sweating or penetration of the liquid through the wall of the pipeline. Selection of jointing method for sectional replacement shall be governed by design pressure of the pipeline. Manufacturer’s advice must also be taken into account. If the pipeline has been shut down.1 Shut down and pressure reduction The need for shutting down the pipeline system for the purpose of carrying out repair or inspection shall be decided by the local area emergency coordinator in consultation with senior pipeline personnel based on the type of defect and the possible consequences. decommission and the replace the defective section with pipe meeting the requirements of the codes and standards. 3.2 Repair options The preferred option of repair is to take the pipeline out of service. depressurisation and draining of the system is necessary.6. defect assessment methods and major activities following reporting of a pipeline leak are similar to those indicated for CS pipelines at section 2. 3. It is difficult to identify the minor weeping defects in buried GRP pipelines (Minor weeping can only be identified during hydrotesting).6. depending upon the type of repair and shall be recorded in the close out report.This is the most common type of Level-I defect in a GRP pipeline system. The system pressure after completion of the repair shall be decided by the engineerin-charge. If design pressure of the pipeline is less than or equal to 40 barg. shall be carried out using flanged joints. laminated joint shall be used. in the pipelines having design pressure more than 40 barg.5 of this document. weeping of a pipeline due to over pressurisation is identified an immediate shutdown of the pipeline must be initiated. The cutting of glass fibre reinforced plastic pipes can be done by means of a hacksaw or 4” grinding disc for diameters up to 100 mm.3.2 Cleaning of the defect area The surface of affected area of the pipeline shall be cleaned to allow for repair. as the joint reliability depends to a large extent on the squareness of the cut. The pipe section must be free from oil. 3. dry rag or compressed air that is dry and free from oil. inspection etc. 3. All surfaces to be adhesive bonded shall be cleaned Page 33 of 76 . grease and dust.Selection of emergency repair options .3.GRP pipelines Type of Defect Temporary location Nil repair Permanent repair location Minor leak in straight Sectional replacement * portion Major leak in straight Nil Sectional replacement portion Weep in straight Nil Sectional replacement * portion Rupture Nil Sectional replacement Leaks in joints and Nil Replacement of the fitting/joint fittings Leakage through road Nil Sectional replacement and wadi crossings * Minor leaks or localised weeping defects can be repaired by over wrapping up to 40 barg design pressure. The cross section shall be straight and perpendicular to the pipe axis. Pipes of larger diameter should be cut by grinding with a diagrit or carborundum-grinding disc. Dust removal shall be carried out using a clean dry brush.1 Cutting of the Pipeline The section of the pipeline to be replaced shall be minimum 1000mm (500mm on either side of defect) more than the length of the defect The pipe section to be cut should be marked and carefully sectioned.3 Repair activity procedures The activities detailed below shall form part of the overall repair works. Adequate cleaning is essential at the joint where the existing pipeline is to be bonded to a new spool piece.6.0 mm. Pipe up to 100 mm nominal diameter shall be square to within 1. Table 3 . (Refer Table 3). Alternative equipment used for cutting shall be subject to the manufacturer’s approval prior to start of work.6. 3.5 mm whilst cuts on larger diameter pipes shall be square to within 3.6.GU-379 Pipeline Emergency Repair Manual The following repair options are recommended depending upon the type of defect. [Refer Appendix 9]. these defects can be repaired by over wrapping. For major leak/rupture in straight section.6. In case. In case of minor leak or localised weeping due to impact damage is identified in the straight portion of the pipeline. it is recommended to replace the complete fitting. Page 34 of 76 . A pipe section containing the leaking joint shall be cut at 500 mm from the leaking joint in both upstream and downstream directions and a new pipe section shall be installed.3.6. sectional replacement shall be carried out for such leaks. use of incorrect torque for tightening of the flange bolts. Pipeline section replacement involves cutting out of the defective portion and installing a new spool piece of compatible properties to the existing pipeline. In case of flanged joints.3 Repair of joint leaks Repair of leaks through adhesive bonded. 3. The selection of jointing method depends on design pressure of the pipeline. For leaks attributed to gaskets. Replacement of the fitting involves the same procedures as specified for straight sections described in Section 3.6.3. provided the design pressure of the pipeline is less than or equal to 40 barg. incorrect sequence of tightening of flange bolts or physical damage to the flange. the design pressure is >40 barg.3. The brush or cloth to be used for cleaning should be free from harmful substances. The qualified procedure of laminated joint shall be used for joining the new section with existing pipeline. laminated. Use of metal brushes or harmful solvents for cleaning of threaded joints is not advised.3. The contact surface of the existing pipeline to be bonded shall be prepared in line with jointing procedure. a damaged gasket.3.2 Repair of leaks in GRP pipe fittings For leaks in fittings (minor/major/rupture/weep).3 Emergency repair methods – GRE pipelines 3.3. sectional replacement of such pipelines shall be carried out using flanged joints as per Manufacturer’s repair procedures.3.1 3. leaks can be caused due to the wrong type of gasket being fitted. elastomeric seal and threaded joints necessitates cutting out the joint.GU-379 Pipeline Emergency Repair Manual using acetone. are constructed using threaded joints. 3.3. they shall be replaced by the correct type for the application and the flange bolts tightened to the manufacturer’s recommendations. sectional replacement shall be carried out.6.1 Repair of leaks in straight pipe section The type and nature of the defect shall dictate the repair procedure to be followed.6. Laminated joint shall be used for joining the new section with existing pipeline up to 40 barg design pressure.3. The pipelines designed for more than 40 barg pressure. GU-379 Pipeline Emergency Repair Manual 3. shall be used for sand padding.5.0 metre - Compacted ground: distance from battered edge of trench shall be 1. 7. Page 35 of 76 .5 Detailed Close Out Repair Report The contents of closeout report for GRP pipelines shall be similar to that of CS pipeline repairs closeout report indicated at section 2.3. Windrow shall be reinstated. After completion of the initial backfill layer.6. including the section used for temporary crossings. Hand shovel and wooden hand-ramming device shall be used for the placement of sand under the pipe. The depth of the sand padding over the top of the pipe shall be at least 300 mm. Screened soft sand. Sand shall be lowered into the trench with a mechanical shovel and hand spread uniformly around the pipe. Sand on top of the pipe shall be shaped to the natural angle of repose. the remaining backfill shall be finished to a level slightly above the natural grade and shall be thoroughly compacted by means of a compacting vibrator. the initial layers of final fill shall be carefully lowered into the trench from each side by mechanical shovel ensuring that the backfill material is deposited carefully to avoid disturbing the sand padding. these shall be reinstated to their original contour and condition. 4. The mechanical excavator shall maintain the following minimum safe distances (which shall be clearly marked by a line of bunting) from the edge of the trench: - Rock: distance from edge of trench shall be 1.5 metre - Soft sand with trench sides battered to a minimum slope of 2:1: distance shall be 2 metres. free of rock and foreign matter. The minimum compacted depth of padding below the pipe shall be 150 mm. Reference should also be made to ERD 38-11 and SP-1247 for details on reinstatement.6. Screened excavated material from the location shall be used (after the removal of any rock and boulders) on top of the sand. 3. In order not to damage the sand padding. 3. Where the excavation crosses wadis or ditches with lined or otherwise improved surfaces. 2. 6.7.4 Procedure for sand padding and backfilling of the trench 1.7 of this document.3. 5. 8 Quality Programme during Repair The repair works shall be conducted in accordance with the quality management system as required for ISO 9000. The qualification tests shall be carried out with all PDO approved GRP manufacturer pipes with a view to verify the compatability of resin to be used for laminated joints.9 Emergency Repair Kit The repair crews shall be equipped with all suitable equipment as required for the pipeline being repaired and shall carry an adequate range of fully compatible spare pipe and fittings. In addition the following tools and consumables shall be carried: 1. 3. All repair work shall be carried out under the supervision of approved emergency repair contractor who shall be responsible for maintaining comprehensive records of the repair activities. “one fit for all” philosophy is adopted. sliding gauge.7 Emergency Repair Procedure Qualification Sectional replacement is the only possible repair method for restoring the long trem integrity of the pipeline. 3. Measuring tape. PDO shall engage one of the four approved GRP vendors for procurement and supervision related activities for the emergency repair of the GRP pipelines. pipe marker (pen) 3. Cargo latching belts and slings 5. Similarly. Winches or Pullers. The approved vendor shall develop a detailed repair procedure including cleaning. if design pressure of the pipeline is more than 40 barg. A high level of inspection shall be maintained for all works to ensure compliance with the requirements of the relevant specifications and procedures. The laminted joint shall be used for connecting the new section with existing pipe sytems for the pipelines having design pressure less than 40 barg. For procedure qualification. Temperature and relative humidity measuring equipments 2. sectional replacement shall be carried out using flanged joint. To minimize the emergency material.GU-379 Pipeline Emergency Repair Manual 3. The qualified and approved jointing procedure should be used for sectional replacement in all cases. Grinders and Grinding Disks 6. cutting and jointing of the exiting pipeline with new pipe section. This procedure along with testing plan shall be submitted to PDO for review and approval. It means highest rating pipe for a nominal diameter shall be procured from one of the approved vendor and same pipe shall be used for sectional replacement for all rating for that nominal diameter. Pipe shavers (as supplied by the pipe manufacturer) 4. Drilling machine and Flapper wheels (grit 40-60) Page 36 of 76 . GU-379 Pipeline Emergency Repair Manual 7. Emery Paper 8. Solvent cleaner, cleaning rags 9. PPE (gloves, eye protection, dust mask) Page 37 of 76 GU-379 Pipeline Emergency Repair Manual 4.0 Emergency Repair of Subsea Carbon Steel Pipelines 4.1 General The integrity of sub-sea pipeline systems is very important for the operators for economical, operational and environmental reasons. Once commissioned, the sub-sea pipelines must give continuous service with minimum interruption. However, submarine pipelines generally are operated in a highly corrosive and inaccessible environment. PDO operates a few sub-sea export pipelines for loading crude oil and handling white oil refinery products to tankers at MAF area. The total length of submerged section of these pipelines is approximately 5000m. These include 30” SBM1 East - crude export pipeline. 30” SBM1 West - crude export pipeline. 40” SBM2 - crude export pipeline. 10” Product lines – Shell market lines (6 nos SBM/1/2/3). The integrity of crude oil, product-loading lines is highly important from operations point of view. The crude oil export pipelines are mainly operated under gravity flow conditions. Due to operational and tanker requirements all the submerged crude/product loading lines are critical and there is no specific standby line for crude oil export. Any leaks on these pipelines will have a major effect on the marine environment and reputation with longer-term effects on loading operations; hence any of these pipeline leaks are required to be attended on emergency basis. This manual identifies the possible catastrophic defects (level–I defects) and specifies the appropriate repair methods for PDO sub-sea pipelines. 4.2 Scope This part of the document details the possible emergency repair methods for PDO offshore loading lines. The defects considered are those that could be encountered during the operation of the sub-sea pipelines. The type of defects, defect classification and categorisation of defects, the repair options for sub-sea CS pipelines are similar to that of buried onshore CS pipelines specified in section 2.0. The additional specific requirements for emergency repair of offshore sections of loading lines are briefly detailed in this document. The support facilities required for emergency repair of sub-sea pipelines, such as technical specification of required facilities on the surface support vessel, diving expertise required for carrying out the necessary repair, specific requirements for under water clamping and hyperbaric welding etc., are not detailed in this document. Page 38 of 76 GU-379 Pipeline Emergency Repair Manual 4.3 Causes of Defects The possible reasons for sub-sea pipeline defects are 1. Third party damage 2. Excessive operational loads/errors 3. Corrosion (internal / external) 4. Manufacturing / construction defects 4.4 Level – I Emergency Defects The major activities related to Level-I emergency repairs are categorised into 1. Leak detection 2. Leak assessment survey 3. Decide the repair option based on damage assessment survey 4. Mobilization of emergency repair crew, equipment and carryout the repair work Note: Points 3 & 4 have been covered in brief. 4.4.1 Leak Detection It is necessary to identify the leak location as soon as possible to minimize spill of hydrocarbons and impact on the environment. The sub sea pipeline leaks are divided into minor leaks and major leaks, which is in line with defect categorisation for onshore carbon steel pipelines. The minor leaks are mainly pinhole leaks or crack leaks. The pinhole leak is a small perforation in the pipe wall and is generally the result of either corrosion pits or weld defects or material defects or external damage. A small pinhole leak may go undetected for some time until evidence of oil pollution (sighted oily sheen/layers in water) is observed on the water surface. The unusual death of marine life such as small fish etc. in the vicinity of the loading lines also indicates suspected pipe leak. A pinhole may occur below corrosion scales/deposits or under weight coating making the detection very difficult. In the case of a definite leak, the damage will be of such extent that pipeline cannot retain the line pressure. Pressure loss and environmental pollution are the main characteristics of major pipeline leaks. For identifying the suspected leak, an experienced diver shall physically inspect the pipeline and search for evidence of a leak / source of oil pollution. Remote Operated Vessels (ROV) or manned submersibles can also be engaged for leak detection and repair activities, in case the safety of the divers is in question. Following identification of leak location, the defective section shall be clearly marked using buoys. After identifying the location of the leak, a preliminary inspection must be carried out as quickly as possible to identify the type and extent of the damage sustained to the Page 39 of 76 Based on the preliminary inspection results a qualitative assessment shall be made to assess the condition of the line (leaking / unsafe / badly damaged) in relation to the safety of further diving operations. Depending on the extent of the damage found. governing rules and regulations dictate the repair strategy. Since these tasks require extensive surface support. Temporary repair of pinhole leaks using proprietary sleeves or clamps can be executed without pressure reduction. available under the existing regular marine support contract shall be utilized. which is dependent on type of repair method. the services of the support vessel and diving crew. Exposing the pipe for repair may require excavation of the surrounding area. In case of a major leak or rupture. applicable repair method. that the special equipment used and the diving expertise required for these activities shall be of the highest quality. to minimize environmental pollution and for carrying out permanent repair (sectional replacement) in a safe manner.4. The leak assessment survey involves exposure and detail inspection of the defective pipe section to assess and record the condition for subsequent interpretation. Hence the preliminary inspection must be undertaken with extreme caution. 4. implications of leakage on the environment and repair method to be used. The selection of repair method shall be based on pressure containment requirements and corrosivity of internal and external environment. The external concrete coating in the defective area shall be removed using high-pressure water jetting. Provision exists within this contract to call off additional specialist manpower and equipment at short notice. major or rupture and exploring the possible reasons for the leak.4. pipeline shutdown is necessary. the repair may require installation of a repair clamp or replacement of defective section of pipe utilizing connectors or couplings.GU-379 Pipeline Emergency Repair Manual pipeline.2 Leak Assessment Survey After confirmation of the presence and location of the leak. 4. Page 40 of 76 . This assessment is essential to decide upon the repair procedure to be adopted and the safety measures to be taken during the repair. It should be noted.4. the next step involves the assessment and categorisation of the defect into minor. 4.3 Shutdown and Pressure Reduction The requirement of pressure reduction and shut down depends upon severity of the damage. The defective pipe section shall be cleaned to an acceptable level. they can be considered together and a single mobilisation shall be made using one vessel. Since the preliminary inspection requires a rapid mobilisation of diving crew with minimum delay.4 Repair options The company philosophy. Under water video recording facilities give an added advantage for analysis of pipeline damage by experts. The other permanent repair techniques indicated for buried (onshore) CS pipelines are also applicable for sub-sea pipelines. repair operations. repair sleeves. The Plidco Clamp and sleeve has clamping surfaces. machinery. A typical flat bottom barge for emergency repair of sub-sea pipelines shall be of 150 to 250 feet long with valid certification for hull. Good seaworthiness related to its overall dimensions and hull form. The main advantage of mechanical connectors is that this method is fast and underwater (hyperbaric) welding can be avoided. Temporary Repairs Plidco Clamp and sleeve or any other similar Company approved brand sleeves are preferred for temporary repair of sub-sea pipeline leaks (refer to Table 1 – Selection of emergency repair options for CS pipelines). For shallow water applications either a Jack-up or shallow water flat bottom barge can be used. These temporary repairs can be accepted as a permanent repair. 4. availability of resources and cost involved. General construction capabilities should include under water welding and cutting gear together with workshop / repair facilities.). which grip the outside wall to counter end-pull and axial stresses. safety equipment for offshore operations. clamps etc. In the event of pipeline rupture. However. Positioning systems to allow the vessel to accurately fix its position relative to known references and to the pipeline on the seabed. lifting of pipe sections. Page 41 of 76 . For sectional replacement.GU-379 Pipeline Emergency Repair Manual Permanent Repairs The preferred option of permanent repair is to decommission the pipeline.5 Resources In order to perform the sub-sea inspection and leak repair activities. Communications must be good and in preference include telex. The vessel deck crane capacity must be in excess of expected loads (for lowering. The crane must be rated for offshore use and must be equipped to assist diver operations down to 50 meters water depth. The vessel should have a well-trained and integrated crew familiar with the work and the construction. The vessel should have following main features. this option is seldom exercised due to the time constraint. cut the defective section and replace it with a new section. mechanical connectors shall be used. the sectional replacement option shall be selected. The requirement will depend upon the type of repair and size of defective pipeline. as well as normal marine side band VHF/UHF and walkie-talkie equipment. an adequate surface vessel will be required. subjected to periodic inspection of these sleeves following installation. emergency materials are stored at four locations. 5. Presently. All identified defects. These locations are Nimr. available Plidco Smith Clamp can be used for minor leaks if adjacent area has sufficient wall thickness. the sources of required resources for tackling any emergency repair work needs to be identified and the relevant repair procedures should be made available for ready reference. In future. However. The Plidco Split Sleeves (or similar) shall be procured for highest rating pipeline for each diameter. expected corrosion rate and risk associated with the pipeline.1 Philosophy The following philosophy has been adopted to establish the quantities of emergency stock material. it is proposed that 3 pipe joints for each diameter at every location shall be stocked from available pipe material. Minor leaks shall be repaired by over wrapping up to a design pressure of 40 barg. all class-I pipelines shall be divided into different groups based on pipe diameter and location of the pipeline. sustained operations may require the services of additional specialist equipment. All class-I pipelines are regularly monitored and inspected by IP and UT.0 Emergency Stock Materials 5. so it is concluded that emergency materials shall be stored for one event at each location for each diameter. The wall thickness and grade of pipe material shall be selected in such a manner that selected pipes can be used for sectional replacement in all pipelines of same diameter at that location without any compatibility issue. For sectional replacement in carbon steel pipeline. which are threatening the integrity of the pipeline. the probability of leakage in a class-I pipeline is minimum. no Plidco Smith Clamp shall be procured. Considering all these aspects. An event includes a pinhole leak. For CS pipelines.GU-379 Pipeline Emergency Repair Manual Whilst the company maintenance barge ‘Fahal1’ fulfils most of the requirements above. Nimr Page 42 of 76 Marmul MPS . The inspection frequency depends on the present condition of the pipeline. For GRE pipelines. 5. Fahud and MAF.2 Loaction and Quantities of Emergency Stock Materials The Emergency Stock Materials are located in following stores. With a view to tackle any emergency situations with the sub-sea loading lines at MAF area. a major leak and a rupture. it is decided that sectional replacement shall be carried out using laminated joints up to 40 barg and flanged spool pieces shall be used for sectional replacement for lines operating at more than 40 barg. Requirement of any additional emergency material shall be discussed with PDO on case to case basis. Marmul. are repaired in a planned manner and chances of any third party damage to the pipeline are minimal. 2 for CS and Section 3. o Location of defect o Defect categorization/type as per Section 2. the potential for fire is greater and therefore the wearing of fire resistant clothing is essential. operating pressure. For raising an emergency alarm the PDO emergency response documents shall be followed.0 Safety 6. explosion or spill have been duly adopted. a hazard assessment must be done immediately and a worksite safety plan produced. material grade. All necessary notification and reporting shall be done as per HSE 97-01 and as described in Section 2. In cases of repairs to a leaking pipeline. For welding on live lines. WPS) o Repair material required (list. the repair method to be used in line with this manual. These documents outline the contingency plans and safety measures to be adopted.7. OD. including availability of adequate fire protection equipment. The flammability level in the area should be checked with a combustible gas detector. The engineer-in-charge shall prepare a specific action plan indicating the damage identified.GU-379 Pipeline Emergency Repair Manual Fahud MLPS Mina Al Fahal Nimr The list of recommended emergency materials is attached as Appendix 8. Information contained in the material data sheet for the product should be consulted to determine the volatility and toxicity characteristic. location and responsible party for arranging and transporting the repair material) o Details of contractor who will carry out the repair (name/telephone) o Safety precautions.5 for GRP and SP-1235 o Pipeline service and details (fluid transported. tools required. wall thickness) o Repair method (repair option.7 above. 6.1 Safety requirements during repair of emergency defects It is the responsibility of the engineer-in-charge to ensure the repair operations are carried out in a controlled and safe manner. A hazard zone should be established by determining the amount of hydrocarbon vapours in the area. The plan shall contain the following minimum information: o Name and telephone number of the PDO commander on the scene. The repair operations should proceed only after the requisite safety precautions for dealing with any emergency including fire. The personnel involved in the repair shall be provided with adequate personnel protection equipment in line with SP-1234 and SRD-S-01 and shall work to the ‘Buddy’ (non-working alone) system as outlined in PR-1081. The recommended safety measures shall be based on the type of defect and the level of leak as outlined in SP-1075 and HSE 97-13.5. Atmospheres above 10% of the lower explosive limit (LEL) shall be Page 43 of 76 . All precautions and safety measures to be taken shall also be specified in the plan. An area assessment shall explore the following minimum aspects: 1. This will determine the type of the protective equipment required for all personnel working in the area. all necessary warning signs and restricted access must be put in place. 4. 6. SP1005 and SP-1007 shall be followed. The excavation and its surrounding area should be tested and continuously monitored with combustible gas detectors or oxygen monitors or both to ensure the atmosphere remains safe. In cases of spills the methods and procedures outlined in PR.g. Adequate ventilation is essential throughout the work duration. any hydrocarbon saturated earth should be removed. Those above 50% LEL shall not be entered. 2. Electrical earthing bonds must be provided due to the possibility of an electrical potential on the pipeline.2 Accidental releases Every effort shall be made to contain any spill or accidental release.1084. 2. curing agents. and catalysts which can produce irritation when allowed to come into contact with the eyes or skin. 3. If the hazard area extends into public areas. the oxygen level must be checked and monitored. The flammable hazard zone must be demarcated to prohibit movement of equipment and other ignition sources into the zone. 3. rubber gloves and barrier creams. If the repair is to be done in a confined space such as a trench. 4. In addition. A spill should be diverted away from sensitive areas where possible by cutting drainage channels from the leak site to a specially dug pit or a bunded collection point Page 44 of 76 . safety glasses. The leak site should be barricaded and marked to prevent the possibility of accidents or injuries. villages. Under no circumstances should burning equipment be used for GRP repair works 2. Adequate personnel protection must be worn e. Special precautions shall be taken when working with resins. 5. face masks. Toxicity testing should be made with direct reading instruments that include colorimetric tubes. All redundant components shall be correctly disposed. PR-1089. 4. 3. the following safety measures are specifically applicable for GRP pipeline repair works :1. Other essential safety measures that shall be followed include:1.GU-379 Pipeline Emergency Repair Manual declared hazardous and access should be restricted. Before start of hot work. reduce the contaminated area and to divert the oil away from sensitive areas such as wadis. Any accidentally contaminated skin area shall be thoroughly washed with soap and water. facilities and sources of ignition. 5. Special precautions shall be taken to prevent inhalation of the glass fibre dust. If necessary.GU-379 Pipeline Emergency Repair Manual at least 50m away from the area so the oil can be collected in a safe and controlled manner. Page 45 of 76 . Particular attention shall be taken to ensure that the oil does not flow into a falaj system as this could allow the oil to travel a considerable distance and contaminate populated/agricultural areas. additional pits or bunded areas should be constructed to take any overflow. III Production Operation Emergency Response Document Emergency Response Document Flow Line Suspension/Abandonment Gas Freezing.8) SP-1246 Specification for Painting and Coating of Oil and Gas Production Facilities PDO Procedures PR-1011 PR-1060 PR-1066 PR-1067 PR-1068 PR-1071 PR-1073 PR-1074 PR-1076 PR-1081 PR-1082 PR-1084 PR-1089 PR-1146 PR-1246 PR-1275 Page 46 of 76 Pipeline Remedial Works HSE Management Procedure _ Communicating & Reporting Emergency Response Document Section 2II.4 and B 31.GU-379 Pipeline Emergency Repair Manual 7.60. Purging and Leak Testing of Process Equipment Flushing Flow Lines Isolation of Process Equipments The ‘Buddy System’ Procedure Pipeline Pigging Procedure Spills Clean-up and Site Restoration Procedure Spillage Reporting Procedure Flow Line Cold Cutting Procedure Emergency Response Document Emergency Response Document . Contingency Plan. Abandonment and Restoration Specification for Fire and Explosion Risk Management Specification for Welding on Pressurised Pipes (Amendments/ Supplements to DEP 30.Aqueous Effluents Specification for Accidental Releases to Land and Water Waste Management Site Preparation. Safety and Environment Specification (PPE) SP-1235 DEP 31.12-PDO Pipeline Repairs (Amendments/Supplements to ASME B 31.10. Vol.40.30) SP-1176 Non-Destructive Examination (Amendment/Supplement to ASME V) SP-1177 Welding of Class I Pipelines (Amendments/Supplements to API 1104) SP-1208 Pipeline Construction Specification SP-1210 Pipeline Operations and Maintenance SP-1211 Pipeline Engineering SP-1234 Health.0 References If no revision or issue date is mentioned reference shall be made to the latest revision in force at the time of issue of this Manual PDO Engineering Reference Documents ERD 38-11 Guidelines for Excavation and Working around Live Pipelines PDO Specifications SP-1005 SP-1006 SP-1007 SP-1009 SP-1012 SP-1075 SP-1167 Emissions to Atmosphere HSE specification .60. 38 31.GRP Piping Page 47 of 76 .31 31.30.30.8 Gas Transmission Pipelines API RP 1107 Pipeline Maintenance Welding Practices API RP 2200 Repairing Crude Oil.10 31. Investigation. and Product Pipelines API RP 2201 Safe Hot Tapping Practices in the Petroleum & Petrochemical Industries API Std.40.30 31.38. Piping and Equipment Line Pipe for use in Oil and Gas Operations Under Non-sour Condition Line Pipe for use in Oil and Gas Operations Under Sour Condition Hydrostatic Pressure Testing of New Pipelines Pipeline Leak Detection International Standards ASME B 31.GU-379 Pipeline Emergency Repair Manual PR-1276 PR-1506 Std Procedure Qualification Record for Welding on to Pressurised Pipes Pipeline Hot Tap Management Procedure PDO Guidelines GU-273 Permit to Work System PDO HSE Standards HSE 97-01 HSE 97-13 SRD-S-01 SRD-S-03 Incident Notification.40.40.60.40.11 Hot-Tapping on pipelines.19 GRP Pipelines and Piping Systems (Amendments/ Supplement to ISO 14692 ) BS 7159:1989 Design and Construction of Glass Reinforced Plastics (GRP) piping systems for individual plants or sites API 15LR Low Pressure Fiberglass Line Pipe API 15HR Specification for High Pressure Fibre Glass Line Pipe SP-1247 Construction of Pipeline Systems in Non-Metallic Materials ISO 14692 – Dec 2002 :Part 1 to 4: Petroleum and Natural Gas Industries.10.60. Liquefied Petroleum Gas. Reporting and Follow up FERM Facility Plan Guideline Standard for Respiratory Protective Equipments Standards and Guidance for Personnel Hydrogen Sulphide Monitors PDO Policy PL-30 PDO Emergency Response Policy DEP 31.40. 1104 Welding of Pipelines and Related Facilities API 5L Specification for Line Pipe References specific to GRP pipelines DEP 31.4 Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids ASME B 31.40. GU-379 Pipeline Emergency Repair Manual Appendix-1: Mechanical methods to be used in installation of sleeves Repair sleeve Pipe Lug and bolt method Hydraulic jack Hi-yield chain link Wood skid Repair sleeve halves with side strips shown Pipe Wood skid Standard method Page 48 of 76 Chain clamp method . GU-379 Pipeline Emergency Repair Manual Appendix-2: Plidco Split + Sleeve Studs & nuts in position Test ports End thrust studs End sealing mechanism Page 49 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-3: Plidco Smith + Clamp Force-screw with cone Clamp Draw-bolt Page 50 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-4: Plidco Weld + Cap Page 51 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-5: Fixing arrangement for Plidco Weld + End Page 52 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-6: Plidco Flange + Repair Ring Page 53 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-7: Plidco Flange – Repair + Split Sleeve Page 54 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-8 : List of Emergency Materials (16 Pages) Page 55 of 76 . GU-379 Pipeline Emergency Repair Manual Appendix-9 : Manufacturer Instructions Page 56 of 76 . It does not imply the Plidco Clamp + Ring is capable of resisting thermal forces associated with raising the temperature of the pipeline to the maximum temperature indicated on the label.GU-379 Pipeline Emergency Repair Manual PLIDCO CLAMP + RING INSTALLATION INSTRUCTIONS SAFETY CHECK LIST Read and follow these instructions carefully. Do not exceed the maximum temperature indicated on the label of the Plidco Clamp + Ring. If the pipeline has been shut down. CLAMP + RING COMPONENTS Page 57 of 76 . A Plidco Clamp + Ring is designed for a specific. If necessary. dynamic. repressuring should be done with extreme caution. external and thermal induced forces. Verify the maximum end restraint indicated on the label is sufficient to resist the combination of hydrostatic. Re-pressuring should be accomplished slowly and steadily without surges. please consult Plidco Department 100 for further detail. The maximum temperature indicated on the label refers only to the selection of an allowable stress used in the design of the Plidco Clamp + Ring. Please refer to “design end restraint” described earlier. longitudinal and restraint in units of force. Industry codes and standards are a good source of information on this subject. Do not exceed the maximum end restraint indicated on the label as described earlier. Do not exceed the maximum end restraint indicated on the label of the Plidco Clamp + Ring. which could vibrate the pipeline and fitting. Personnel should not be allowed near the installation until the Plidco Clamp + Ring has been proven. The bolting force generated when assembling the two halves is capable of shaping minor out-of-round pipe. 3. depending on the pipe wall thickness. Survey the outside of the pipe to confirm a circular cross section. The sidebars will be gapped approximately ¼ to ½ inch. With the tie stud bolt lugs in alignment. The tie stud bolt nuts need only be snug. To complete assembly. See Clamp + Ring components. Plidco has available ring gauges that can accurately survey the cross sectional shape of the pipe. Stud bolts and nuts. Maximum allowable ovality is approximately 5%. 4. Hand tighten a nut on each side of the lugs. Assemble the Plidco Clamp + Ring loosely on the pipe. 5. The combination of Page 58 of 76 . making certain the yellow painted ends are matched. 2. An increase in torque on one stud bolt can cause a decrease in torque on neighboring stud bolts. There should be approximately three (3) inches between the Plidco Clamp + Ring and the repair fitting. rust and scale from the pipe surface where the Plidco Clamp +Ring will contact the pipe. 5. FIELD TESTING The Plidco Clamp + Ring is capable of being field tested up to 1½ times its maximum end restrained indicated on the label of the Plidco Clamp + Ring. Lifting devices such as chains. A high pre-stress on the tie stud bolts is undesirable. insert the tie stud bolt. Remove all coatings. Flat spots are very difficult to reshape and bolting force should not be relied on to correct flattened or indented areas. All clamping stud bolts and nuts should be uniformly torqued as indicated in the Plidco Torque Chart the best results are obtained by maintaining an equal gap between the sidebars while tightening The stud bolts. particularly in the area of the clamping section. Clean and lubricate all Plidco Clamp + Ring. cables or lift truck forks should not contact the clamping sections. 4. This area should be a smooth curved surface without indentations of flat spots that could adversely affect proper gripping. the clamping stud bolts should be rechecked at the recommended torque. 1. 2.GU-379 Pipeline Emergency Repair Manual PIPE PREPARATION 1. 3. INSTALLATION Careless handling can damage Clamp + Ring. Prove free and easy nut running prior to installation. A ring gauge should be used for submerged pipelines where visibility is limited. centered over the repair fitting. free of obvious flaws and lubricated with a high grade graphite-oil thread lubricant. When Cf equals 0. it is assumed the studs and nuts are clean. free of obvious flaws and lubricated with a light weight Machine oil. Page 59 of 76 1-1/16 1-1/4 1-7/16 1-5/8 1-13/16 2 2-3/16 2-3/8 2-9/16 2-3/4 2-15/16 3-1/8 3-1/2 3-7/8 70 120 192 284 414 576 777 1019 1296 1643 2033 2478 3560 4914 . The torque values are safe minimums and represent approximately the bolt pre-stress values listed in the table.08 Cf Ft-lbs 0. STORAGE Plidco Clamp + Ring should be stored in a dry environment to prevent any unpainted surfaces rusting.08. external and thermal induced forced anticipated during testing must be considered.08 and 0.500 psi pre-stress 2-3/4—8 4-1/4 5947 8064 10787 14628 3—8 4-5/8 7816 10598 14218 19280 3-1/4—8 5 9966 13514 18170 24639 3-1/2--8 5-3/8 12478 16921 22794 30908 3-3/4—8 5-3/4 15380 20856 28140 38157 4—8 6-1/8 18699 25355 34262 46460 37. free running.500 psi pre-stress 5/8—11 ¾--10 7/8—9 1—8 1-1/8—8 1-1/4--8 1-3/8—8 1-1/2--8 1-5/8—8 1-3/4--8 1-7/8—8 2—8 2-1/4—8 2-1/2--8 95 118 160 162 206 280 259 328 446 385 490 664 561 719 975 782 1008 1368 1055 1368 1855 1382 1800 2441 1758 2302 3121 2226 2928 3969 2758 3633 4927 3360 4444 6025 4826 6412 8694 6664 8886 12048 47.15.15 Cf Nm ft-lbs Nm 52. PLIDCO TORQUE CHART Nominal diameter of stud bolts ( inches) Wrench Opening across flats Clamping Studbolt Torque Values* 0.GU-379 Pipeline Emergency Repair Manual hydrostatic. dynamic. it is assumed the studs and nuts are clean. free running.15. 0. When Cf equals 0.500 psi pre-stress 4-1/4—8 6-1/2 17735 24050 32540 44123 4-1/2--8 6-7/8 21082 28586 38723 52508 4-3/4—8 7-1/4 24822 33659 45643 61891 5—8 7-5/8 28983 39302 53344 72334 5-1/4—8 8 33585 45539 61864 83887 5-1/2--8 8-3/8 38647 52405 71245 96609 5-3/4—8 8-3/4 44195 59929 81529 110556 6—8 9-1/8 50249 68139 92761 125783 Torque values shown in the table represent two different coefficients of friction (Cf). 218 0. ground movement or any combination thereof. Minimum Pipe Wall Thickness For Plidco Weld + Ends Nominal Pipe Size (inches ) 1½ 2 2½ 3 4 6 8 10 12 14 16 & larger Page 60 of 76 Wall Thickness (inches ) 0.200 0. (a) Pipe Not anchored A joint in which the pipe ends could move when subjected to internal or external forces. It assumes that the pipeline is suitably Anchored by welding.280 0. underwater currents.365 0. The assigned Plidco Weld + Ends Pipe Not Anchored rating considers only the end force created by the internal pressure. Observe the pressure and temperature ratings on the label of the Plidco Weld + Ends coupling.GU-379 Pipeline Emergency Repair Manual PLIDCO WELD + ENDS INSTALLATION INSTRUCTIONS SAFETY CHECK LIST Read and follow these instructions carefully. such as internal pressure.276 0.237 0.322 0. It does not consider any additional external forces such as temperature expansion and contraction. These additional external forces must be determined. temperature expansion and contraction.409 0.237 0. underwater currents.438 0. Plidco Weld + Ends Anchored pipe rating is the maximum pressure at which the pipeline can be operated. Determine the type of joint that the Plidco Weld + Ends coupling is expected to connect. ground movement or any combination thereof. by the use of an appropriately rated Plidco Clamp + Ring or by other customer proven techniques.500 . (b) Anchored pipe A joint in which the pipe ends would not move when subjected to these same forces. Be absolutely certain that the correct seal material has been selected for the intended use. See (a) and (b) below and determine the appropriate rating from the ratings listed on the label of the Plidco Weld +Ends coupling. a Plidco Clamp + Ring should be used. Do not exceed the maximum appropriate pressure indicated on the unit. If any of these forces cannot be restrained by customer proven techniques. 2. C 225 °F . free of coating and burrs and lubricated to prevent abrasion to the seal. The pipe surface in the area of the repair should be clean. This will be needed later if the Plidco Weld + Ends is welded to the pipe. For badly misaligned or out of round pipe. Measure and record dimension “D” as shown in Figure 3. It must be determine that the lubricant is compatible with the product in the pipeline. Follow applicable B31 codes during re-pressuring. This would be eliminate the risk of damage to the seal while slipping the Plidco Weld + Ends coupling over the end of the pipe (See Figure 1) INSTALLATION The seal can be damaged by careless handling. The following chart indicates the lubricants that are recommended for the various seal materials. A Plidco Clamp + Ring should be considered whenever wall thickness is less than those listed. 2. Lifting devices such as chains. Pipeline should be evenly supported before re-pressuring.GU-379 Pipeline Emergency Repair Manual Pipe wall thickness less than those listed may be pushed inward by the force of the clamp screws. B. it is helpful grind a pilot bevel with a generous taper on the pipe. Pipelines should be carefully blocked at elbows and bends to prevent pullouts caused by internal and external forces. If the Plidco Weld + Ends coupling is welded or a suitable Plidco Clamp+ Ring is used. Coat all exposed surfaces of the seal material with a lubricant. 1. Buna-N Page 61 of 76 A. or a Plidco Clamp + Ring should be used. PIPE PREPARATION 1. even if the pipe has an adequate wall thickness. A Plidco Clamp + Ring should also be considered where high external forces (such as underwater Currents or thermal contractions) are anticipated. cables or lift trucks forks should not contact the seal. Failure to do so can result in the seal being damaged or pulled from its grooves. it can be considered an anchored joint. Slide the Weld + Ends coupling back to the mark to divide the coupling equally over the joint. C 250 °F 450 °F 250 °F 250 °F 500 °F 750 °F 3. 4. Clamp screws do not consider any additional external forces or stresses imposed on the pipeline. B. 5. Mark on the pipe one-half the Plidco Weld + Ends coupling’s length from the middle of gap (recommended gap not to exceed ¾ inch). Do not exceed the Pipe Not Anchored Rating listed on the label of the Plidco Weld + Ends until subsequent welding has been completed. C A. C A. C C B. B. Slide the pipe into the Plidco Welds + Ends coupling completely. Clamp screws are designed for the assigned Plidco Weld + Ends Not anchored rating which considers only the end force created by the internal pressure. (See Figure 2). C A. The shanks are mild steel and fully weldable. Clamp screws should be tightened evenly. Clamp screws have case hardened cup points which are used to secure the coupling to the pipe.GU-379 Pipeline Emergency Repair Manual Viton Silicone Neoprene Aflas Teflon Kevlar Petroleum based lubricant = A Silicone based lubricant = B Glycerin based lubricant = C A. Accurate clamp screw torque values are very important when the Plidco Weld + Ends coupling is used on a pipeline joint that is NOT ANCHORED. Page 62 of 76 . B. maintaining an equal space between the pipe and the coupling using the recommended torque values. B. This assumes a 1. They should be tightened gradually and uniformly around the circumference. There may be need to select a different joint efficiency based on level of inspection or your company’s welding policy. which are of equal or greater tensile strength than the pipe. First. The smoother and more streamlined the weld. Page 63 of 76 . avoid notches and undercuts. which can cause leakage. A final torque range. rupture or explosion with attendant serious consequences. Operating pressure must not exceed the maximum appropriate Pipe Anchored or Pipe Not Anchored Rating. Carefully control the size and shape of the circumferential fillet weld. Thrust Screws 3/8-16 ½-13 5/8-11 Torque Range ft-lbf 20-25 30-40 70-80 Nm 28-34 41-55 95-109 8. Use recommended torque values in the chart below. The size of the fillet weld should be at least 1. 9.0 joint efficiency. Thrust screws activate the seals. shown in the chart above. Cup point Clamp Screws 5/8-11 ¾-10 Minimum Torque ft-lbf 100 150 Nm 136 240 7. Strive for a concave faced fillet weld with streamlined blending into both members. The weld is required to anchor the joint and give longitudinal stability to the pipeline. Industry codes and standards are a good source of information on this subject. slowly and steadily without surges. the greater the resistance to fatigue failure.GU-379 Pipeline Emergency Repair Manual 6. It will be necessary to make many circuits around the coupling before completing the thrust screw torque operation. Check all clamp screws to make certain each has received at least the minimum torque specified in chart below. Repressuring after the repair should be done with extreme caution. They are made of mild carbon steel and are fully weldable. Use absolutely dry electrodes. FIELD WELDING INSTRUCTIONS Pipeline should be full and underflow. Personnel should not be allowed near the installation until the seal has been proven. will be adequate to complete the assembly. which could vibrate the pipeline and fitting.4 times the wall thickness of the pipe. Then advance each thrust screw about 1/8 of a turn before proceedings to an adjacent thrust screw. Improper weld shape can lead to rapid fatigue failure. The worst Possible shape would be a heavy reinforced convex weld with an undercut. snug all the thrust screws firmly. To prevent damage to the seals. 3. WELDING SEQUENCE 1. It is very important that the field welding procedure closely follow the essential variables of the qualified procedure so that the quality of the field weld is represented by the physical tests performed on the procedure qualification test specimen. Caution should be observed so that welding or pre heating does not overheat the seals. Dimension “D” as measured during the initial Installation. Cut or burn off clamp Screws approximately 3/16” above the outside surface of the coupling and seal weld. These locations are the same distance from the weld as the seal location “C”. Sequence the welding so that the heat is not concentrated in one area. (See Figure 3). 2. There are acceptable filler metal. provided they are proven by procedure qualification. Shielded metal arc welding (SWAW) filler metals listed in API 1104 and 1107 include the cellulose coated electrodes (E-XX10 series) which are often preferred because of the excellent downhill welding characteristics. “Welding of Pipelines and Related Facilities” or RP 1107. If the heat generated approaches the temperature limit of the seal material. Start with the fillet weld to the pipe around circumference and include seal welding the thrust screws.GU-379 Pipeline Emergency Repair Manual Welders and weld procedures should be qualified in accordance with API standard 1104. welding should be discontinued or sequenced to another part of the fitting so that the affected area has a chance to cool. API 1104 and 1107 have easy to follow directions for procedure qualification. (See Figure 3) Page 64 of 76 . Thrust Screws should be cut or burned off flush. monitor the heat generated by welding or preheating. “Recommended Pipeline Maintenance Welding Practices” latest edition. by using temperature crayons or probe thermometers. particularly at location “A” and “B”. One clamp screw near the top may be removed to serve as a vent while welding and also as a final test point for leakage. may now be used to mark off locations “A” and “B” as shown in Figure 3. which is indicated on the label and in the seal lubrication chart. Plidco encourage the use of low hydrogen electrodes (E-XX18) because of their high resistance to moisture pick-up and hydrogen cracking. ozone and radiation. Cover with a dark polyethylene to keep the direct sun light from the seals. Page 65 of 76 . Storage temperatures should not exceed 120 °F (49 °C). Improperly stored Plidco Weld + Ends couplings can cause the gasket material to become cracked and brittle and lose its ability to seal. STORAGE INSTRUCTIONS Plidco Weld +Ends coupling should be stored in a dry environment to prevent the unpainted surfaces from rusting. light. It is best to exclude contamination.GU-379 Pipeline Emergency Repair Manual FIELD TESTING The Plidco Weld +Ends coupling can be field tested up to 1 ½ times the appropriate pipe Anchored or Pipe Not Anchored Rating. Observe working pressure and temperature on the label of the Plidco Split + Sleeve. death. 2. Re-pressuring should be accomplished slowly and steadily without surges. B. Lifting devices such as chains. B. Contact can result the seals being pulled from their grooves. fire. Remove all coatings. C A. C A. property damage and/or harm to environment. which could vibrate the pipeline and fitting. Do not exceed the maximum working pressure. INSTALLATION The seals and Girder Rings can be damaged by careless handling. PIPE PREPARATION 1. Page 66 of 76 . C C B. personal injury. The Plidco Split + Sleeve should never be used to couple pipe unless sufficient end restraint is provided such as with the Plidco Clamp + Ring. rust and scale from the pipe surface where the circumferential seals of the Plidco Split +Sleeve will contact the pipe. C The customer must determine if the lubricant is compatible with the product in the pipeline. If the pipeline has been shut down. B.N Viton Silicone Ethylene Propylene Neoprene Aflas Teflon Kevlar A B C A. cables or lift truck forks should not contact the seals or girder Rings. B. When repairing an active leak. Petroleum based lubricant : Silicone based lubricant : Glycerine based lubricant : Buna. C B.GU-379 Pipeline Emergency Repair Manual PLIDCO SPLIT + SLEEVE INSTALLATION INSTRUCTIONS SAFETY CHECK LIST Read and follow these instructions carefully. Industry codes and standards are a good source of information on this subject. repressuring to test the seals after repair should be done with extreme caution. (See Figure 1) 1. Do not exceed maximum working pressure or temperature as indicated on the unit. The Plidco Split +Sleeve has no end restraint in its unwelded condition. extreme care must be taken to guard personnel. Coat all exposed surfaces of the seals with a lubricant. and if so utilized could result in explosion. The seal can tolerate minor surface irregularities up to 1/32”. C A. Severe injury or death could result. C A. B. The following chart indicates the lubricants that are recommended for various seals. Personnel should not be allowed near the repair until the seal has been proven. GU-379 Pipeline Emergency Repair Manual 2. Assemble the Plidco Split+ Sleeve around the pipe making sure the yellow painted ends are matched and that the fitting is centered over the leak and damaged area as much as possible. Sometimes it is helpful to loosely assemble Page 67 of 76 . Clean and lubricate all stud bolts and nuts. 3. and prove free and easy nut running prior to installation. 6. To complete assembly. They are also the preferred electrode for seals welding the stud bolts and nuts. repressuring to test the seals after repair should be done with extreme caution. Improper weld shape can lead to rapid fatigue failure which can cause leakage. ALL stud bolts should be rechecked at the recommended torque. Repressuring should be accomplished slowly and steadily without surges which could vibrate the pipeline and fitting. by using temperature crayons or probe thermometer. These are acceptable filler. Page 68 of 76 . provided they are proven by procedure qualification. with streamlined blending into both members. The size of the fillet welds should be at least 1. the slightest increase in torque on one studbolt can cause a decrease in torque on neighboring studbolts.” latest edition. It is very important that the field welding procedure closely follow the essential variables of the qualified procedure so that the quality of the field weld is represented by the physical tests performed on the procedure qualification specimen. API 1104 and 1107 have easy-to-follow directions for procedure qualification.” or RP 1107 “ Recommended Pipeline Maintenance Welding Practices.GU-379 Pipeline Emergency Repair Manual the Plidco Split + Sleeve to one side of the leak. rupture or explosion with attendant serious consequences. 4. The best results are obtained by maintaining an equal gap all around between side bars while tightening the studbolts. If the heat generated approaches the temperature limit of the seal material which is indicated on the label. particularly near the area of the seals. Industry codes and standards are a good source of information on this subject. 5. avoid notches and undercuts. Keep in mind. Monitor the heat generated by welding or preheating. FIELD WELDING INSTRUCTIONS If the pipeline has been shutdown. Plidco encourage the use of low hydrogen electrodes ( E-XX18) because of their high resistance to moisture pick-up and hydrogen cracking. Strive for a concave fillet weld. Personnel should not be allowed near the repair until the seal has been proven. then reposition it centered over the leak. Shielded metal arc welding (SMAW) filler metals listed in API 1104 and 1107 include the cellulose coated electrodes (E-XX10) series which are often preferred because of the excellent downhill welding characteristics. Carefully control the size and shape of the circumferential fillet welds. Do not exceed maximum working pressure. All stud bolts and nuts should be uniformly torqued as indicated by the Plidco Split +Sleeve Torque Chart. The side bars are grapped approximately 1/8” when the Plidco Split +Sleeve is fully tightened. Use absolutely dry electrodes which are equal or greater tensile strength than the pipe. Welders and weld procedures should be qualified in accordance with API Standard 1104 “ Welding of Pipelines and related Facilities. Cellulose coated electrodes are not recommended for seal welding the stud bolts and nuts. metals.4 times the wall thickness of the pipe. This assumes a 1.0 joint efficiency. Sequence the welding so that the heat is not concentrated in one area. They are made of AISI 4140 steel with a high carbon equivalence. 6. ozone and radiation. Cover with a dark polyethylene to keep the direct sun light from the seals. Re-torque stud bolts and nuts 5. Seal-weld around bottoms of nuts to side bars. Improperly stored Plidco Split + Sleeves can cause the seal material to become cracked and brittle and lose its ability to seal. light. It is best to exclude contamination.GU-379 Pipeline Emergency Repair Manual welding should be discontinued or sequenced to another part of the fitting so that the affected area has a chance to cool. the problem of hydrogen cracking and pin holes can be reduced. FIELD TESTING THE PLIDCO SPLIT+ SLEEVE The Plidco Split + Sleeve can be field tested up to 1 ½ times its design working pressure. Fillet-weld ends to pipe 3. Storage temperatures should not exceed 120 °F (49 °C). 2. oil dampness or thread lubricant that may be present in the seal weld area. The preheat will dry out nay moisture. PLIDCO SPLIT + SLEEVE TORQUE CHART Nominal Page 69 of 76 Wrench Clamping Studbolt (Torque Values*) . WELDING SEQUENCE 1. It will be necessary to re-torque the studbolts and nuts periodically during field welding because weld contraction causes them to loosen. Seal weld nuts to studbolts. STORAGE INSTRUCTIONS Plidco Split + Sleeves should be stored in a dry environment to prevent the unpainted surfaces from rusting. Caution should be observed so that welding does not overheat the seals. Seal-weld side openings 4. By using low hydrogen electrodes ( E-XX18) and a modest preheat ( do not exceed 200 degree F). Seal welding the grade B-7 studbolts of a Plidco Split + Sleeve is the most difficult phase of field welding. 15.08 and 0. When Cf equals 0. free running.15 Cf Nm ft-lbs Nm 25.08 Cf ft-lbs 0. 5/8—11 ¾--10 7/8—9 1—8 1-1/8—8 1-1/4—8 1-3/8—8 1-1/2—8 1-5/8—8 1-3/4—8 1-7/8—8 2—8 2-1/4--8 2-1/2—8 Page 70 of 76 1-1/16 1-1/4 1-7/16 1-5/8 1-13/16 2 2-3/16 2-3/8 2-9/16 2-3/4 2-15/16 3-1/8 3-1/2 3-7/8 33 57 91 135 197 274 370 485 617 782 968 1180 1695 2340 . 0. free of obvious flaws and lubricated with a light weight machine oil.GU-379 Pipeline Emergency Repair Manual diameter of stud bolts ( inches) Opening across flats 0.08. free of obvious flaws and lubricated with a high grade graphite-oil thread lubricant. The torque values are safe minimums and represent approximately the bolt pre-stress values listed in the table. it is assumed the studs and nuts are clean. When Cf equals 0. it is assumed the studs and nuts are clean. free running.15.000 psi pre-stress 45 56 76 77 98 133 123 156 212 183 233 316 267 342 464 372 480 651 502 651 883 658 857 1162 837 1096 1486 1060 1394 1890 1313 1730 2346 1600 2116 2869 2298 3053 4140 3173 4231 5737 23000 psi pre-stress 2-3/4--8 4-1/4 2880 3904 5224 7083 3—8 4-5/8 3785 5133 6885 9336 3-1/4--8 5 4826 6545 8799 11931 3-1/2—8 5-3/8 6043 8194 11037 14967 3-3/4—8 5-3/4 7447 10099 13626 18477 4—8 6-1/8 9055 12278 16590 22497 18.800 psi pre-stress 4-1/4—8 6-1/2 8891 12075 16313 22120 4-1/2—8 6-7/8 10569 14331 19413 26324 4-3/4—8 7-1/4 12444 16874 22882 31028 5—8 7-5/8 14530 19703 26743 36263 5-1/4—8 8 16837 22830 31014 42055 5-1/2—8 8-3/8 19375 26272 35717 48433 5-3/4—8 8-3/4 22156 30044 40873 55425 6—8 9-1/8 25191 34160 46504 63059 Torque values shown in the table represent two different coefficients of friction (Cf). N Viton Silicone Neoprene Aflas Teflon Kevlar : : : A B C A. 4. The seal can tolerate minor surface irregularities up to 1/32”. C C B. When installing a Plidco Flange + Repair Ring on non-leaking flanges submerged under water (or any liquid). rust and scale from the flange surface where the circumferential seals of the Plidco Flange + Repair Ring will contact the flange. Observe working pressure and temperature on the label of the Plidco Flange + Repair Ring. 3. C 225 degree F 250 degree F 450 degree F 250 degree F 250 degree F 500 degree F 750 degree F INSTALLATION The seal and Girder Rings can be damaged by careless handling. B. Page 71 of 76 .GU-379 Pipeline Emergency Repair Manual PLIDCO FLANGE + REPAIR-RING INSTALLATION INSTRUCTIONS SAFETY CHECK LIST Read and follow these instructions carefully. C A. Lifting devices such as chains. C A. B. Prove free and easy nut running prior to installation. Plidco strongly recommends the vents be open during installation to prevent excessive pressure buildup within the fitting due to hydraulic lock. B. Verify the tightness of all threaded vents and connections. B. Clean and lubricate all Plidco Flange + Repair Ring stud and nuts. No end restraint is provided with the Plidco Flange + Repair Ring. Make sure the gap between the flanges is clear to the flange stud bolts. 2. Petroleum based lubricant Silicone based lubricant Glycerine based lubricant Buna. cables or lift truck forks should not contact the seals or girder Rings. Contact can result the seals being pulled from their grooves. The Plidco Flange +Repair Ring may be used with the pipeline in operation or shutdown. Be absolutely certain that the correct seal material has been selected for the intended use. PREPARATION 1. C A. The following chart indicates the lubricants that are recommended and the maximum temperature limit for various seals. C A. B. The customer must determine if the lubricant is compatible with the product in the pipeline. Do not exceed the maximum working pressure or temperature as indicated on the unit. Coat all exposed surfaces of the sealing material with lubricant. The Plidco Flange + Repair Ring should never be used to couple flanges. Remove all coatings. PLIDCO TORQUE CHART Nominal diameter of stud bolts ( inches) Wrench Opening across flats 5/8—11 ¾--10 7/8—9 1--8 1-1/8—8 1-1/4--8 1-3/8—8 1-1/2--8 1-5/8—8 1-3/4--8 1-7/8--8 2--8 2-1/4--8 2-1/2--8 2-3/4--8 3--8 3-1/4--8 3-1/2--8 1-1/16 1-1/4 1-7/16 1-5/8 1-13/16 2 2-3/16 2-3/8 2-1/2 2-3/4 2-15/16 3-1/8 3-1/2 3-7/8 4-1/4 4-5/8 5 5-3/8 Clamping Studbolt Torque Values* 0. SEALANT INJECTION One or more sealant cocks are supplied with each Plidco Flange + Repair Ring.000 psi pre-stress 45 56 77 98 123 156 183 233 267 342 372 480 502 651 658 857 837 1096 1060 1394 1313 1730 1600 2116 2298 3053 3173 4231 4244 5678 5579 7484 7114 9564 8906 11997 Nm 76 133 212 316 464 651 883 1162 1486 1890 2346 2869 4140 5737 7699 10148 12969 16268 Torque values shown in the table represent two different coefficients of friction (Cf). it is assumed the studs and nuts are clean. The torque values shown apply up to and including 700 degree F. To complete assembly. free running. it is assumed the studs and nuts are clean. free of obvious flaws and lubricated with a light weight Machine oil. if desired. 2. 4. Be sure cocks are open before injecting sealant. When Cf equals 0. Open the sealant cocks to allow product to vent while bolting.GU-379 Pipeline Emergency Repair Manual 1. 5.15. Assemble the studs and nuts hand tight. These may be used for venting by removing the button heads while the cocks are closed. free running. The side bars are gapped approximately 1/8” to 3/16” when the Plidco Flange + Repair Ring is fully tightened.15. free of obvious flaws and lubricated with a high grade graphite-oil thread lubricant. The best results are obtained by maintaining an equal gap between the side bars while tightening the bolts. The torque values are safe minimums and represent approximately the bolt pre-stress values listed in the table. 3.08. the stud bolts should be rechecked at the recommended torque. Assemble the Plidco Flange + Repair Ring around the flanges making certain the fitting is centered over the gap between the flanges and that the yellow painted ends are matching.08 and 0. All stud bolts and nuts should be uniformly torqued as indicated by the Plidco Torque Chart. When Cf equals 0. Close cocks and re-install button heads. 0. Page 72 of 76 .08 Cf ft-lbs 33 57 91 135 197 274 370 485 617 782 968 1180 1695 2340 3130 4114 5246 6568 0.15 Cf Nm ft-lbs 25. A good rule to remember is when the rate of leakage decreases the rate of sealant injection should be decreased. Storage temperatures should not exceed 120 °F (49 °C). This does not always give desirable results. These sealants can be injected directly through the sealant cock. Injection should proceed slowly. Often. Occasionally the surfaces to be sealed are unreasonably gapped or badly corroded. Observe for a while to see if a leak develops. STORAGE INSTRUCTIONS Plidco Flange + Repair-Ring should be stored in a dry environment to prevent the unpainted surfaces from rusting. Sometimes a total seal off is instant. These may require sealants which are very coarse and which cannot be pumped through the restriction of standard button heads. during the final phases of seal off. Leakage will usually slow down to a whisper through the flange bolts. Improperly stored Plidco Split + Sleeves can cause the seal material to become cracked and brittle and lose its ability to seal. Generally the leakage will reduce to whispers and the rate of sealant injection should be reduced proportionately.GU-379 Pipeline Emergency Repair Manual Connect a sealant gun to fitting and inject sealant through all button head fittings a little at a time until the Plidco Flange + Repair Ring is full. there is an impulse to pump sealant zealously. The confined sealant. injecting a little at a time through the button head nearest the leak until total seal off is attained. in which case all sealant injection should be stopped. having no where to go. Cover with a dark polyethylene to keep the direct sun light from the seals. Page 73 of 76 . is forced out a previously sealed bolt hole or gasket. It is best to exclude contamination. light ozone and radiation. bolts. OPTIONS: 1. Flange Set Primarily for API 8rd products ≥ 500 PSI. Make use of the undamaged pipe by rethreading the ends in the field allowing for the flange set. If the width of a set of flanges will repair the area. The use of a minimum length nipple may be required to install the flange set. nuts. washers and gaskets. but are limited in pressure rating. The following are the repair methods and the limitations of each: CAUTION: Make sure that the line is properly vented prior to starting repair work. Purchase a prefabricated repair joint designed to mechanically replace a full (9. replace the damaged joint with a new joint which can be shortened in the field to make room for the flange set and a minimum length nipple. 3. OPTION ONE PROCEDURE: Consider the length of the damage. 2.2 of the Recommended Installation Practices for the proper threading method to maintain the system pressure rating. Lower pressure products offer alternative methods to flange sets. Page 74 of 76 .8. Depending on how long the damaged area is.14 Mtrs. nominal) joint of pipe and make room for a flange set. an extra joint of pipe may be required.GU-379 Pipeline Emergency Repair Manual GRE REPAIR PROCUDRES : SMITH FIBER Introduction The repair of Star line pipe primarily involves the installation of a flange set. Reference the field thread rating chart 2. taking into consideration the total laying length of the parts needed to make the repair. If extra pipe is available. a decision must be made as to how to reconnect the line with the flanges. Set includes 2 flanges. Depending on the location of the leak. This method works for API 8rd. Rethread both square cut ends or bell x male adapters. a nipple (long enough to repair the damaged area) and a coupling will be required along with the flange set. The pressure rating of the system can be maintained using this system on any API 8rd product. Cut the damaged area of the pipe using a hacksaw. Remove both remaining ends using (2) Star metal friction wrenches. Replace the damaged joint with the special length repair joints. Remove both remaining ends using (2) Star metal friction wrenches. Install the flange set. Replace with a new joint of pipe.GU-379 Pipeline Emergency Repair Manual Figure 1 OPTION TWO PROCEDURE: Cut the damaged joint using a hacksaw. only in the upset area. Install the flange set. Do not cut the pipe in the pipe body. Figure 2 OPTION THREE PROCEDURE: Cut the damaged joint of pipe using a hacksaw. Figure 3 Page 75 of 76 . Field thread the pipe. Shorten the joint as required to fit the flange set and a minimum length nipple. revise at next issue: Accept.: Ref. This lets DCS or the CFDH ask you about your comments and tell you about the decision. Title: Issue Date: Specification Details Number: Page Number: Heading Number: Figure Number: Comments: Suggestions: User’s personal details Name: Ref.: Recd. issue temporary amendment Comments: Page 76 of 76 To CFDH: Inits.: Date: . They make a record of your comment and send the form to the correct CFDH.: CFDH Actions Recd. Ind. Ind. Decision: Date: Reject: Accept. ambiguous or could be better in this document. Ind.: Signature: Date: Phone: Document Control Section Actions Date: Comment Number: CFDH Ref. The form has spaces for your personal details. Send the form to the Document Control Section (DCS).GU-379 Pipeline Emergency Repair Manual Appendix-10 : User Comment Form User Comment Form If you find something that is incorrect. write your comments and suggestions on this form.