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Iranian Gas Development & Engineering CompanyBASIC AND DETAIL DESIGN OF 40"GAS PIPELINERASHT/SARI/NEKA

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Pipeline Design Criteria

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table of contents1-INTRODUCTION52-Definitions53-Scope54-References55-Units76-Design Data77-Design78-Materials109-Pipeline Route Selection1110-Pipeline Protection and marking1311-Crossings1412-environmental16

1- INTRODUCTIONIranian Gas Engineering & Development Company a subsidiary of National Iranian Gas Company (NIGC). Has intended to perform a 40" gas transmission pipeline about 382 Km in Route of Rasht/Sari/Neka. the Project will be Executed in 2 Phase as Basic & Detail Engineering Contract. The purpose of constructing this pipeline is to transfer 40000103 M3 per day Lean Gas from Rasht Compressor Station to Neka Compressor station and consumers located along side of the pipeline, also because of exist 30" old pipeline the new 40" pipeline will handle a part of existing pipeline duty in about 70 Percent of Overall Pipeline route.2- DefinitionsWithin the context of this document, the following definitions are applicable.ClientIranian Gas Engineering & Development Company (I.G.E.D.C)

ConsultantMiddle East Energy Development Consulting Engineers

ShallIndicates a Mandatory Requirement

ShouldRecommendation or that which is advised

3- ScopeThis specification gives minimum technical requirements for design of onshore pipelines in mentioned project and shall be read in conjunction with project documents.4- ReferencesASME (American Society of Mechanical Engineers)B31.8"Gas Transmission and Distribution Systems" 2008 EditionB16.5"Pipe Flanges and Flanged Fittings up to and including 24" EditionB16.9"Factory-Made Wrought Butt-welding Fittings"B16.11"Forged Fitting, Socket-Welding and Threaded"B16.20"Metallic Gasket for Pipe Flanges, Ring-Joint, Spiral-Wound and Jacketed"B16.25"Butt-Welding Ends"B16.47"Large Diameter Steel Flanges"

API (American Petroleum Institute)6D"Specification for Pipeline Valves" 5L"Specification for Line Pipe" 44 Edition 20116FA"Fire Test for Valves"RP1102"Steel Pipelines Crossing Rail Roads and Highways" 6th Edition 19931104"Welding Of Pipelines and Related Facilities"ASTM (AMERICAN SOCIETY FOR TESTING AND MATERIAL)A370"Standard Test Methods and Definitions for Mechanical Testing Of Steel Products"ASTM SERIES (MATERIAL)MSS (Manufacturers Standardization Society)MSS-SP-25"Standard Marking System for Valves, Fitting, Flanges and Unions"MSS-SP-44"Steel Pipeline Flanges"MSS-SP-75"Specification for High Test Wrought Butt-Welding Fittings"MSS-SP-97"Integrally Reinforced Forged Branch Outlet Fitting, Socket Welding, Threaded and Butt-Welding Ends"IPS (Iranian Petroleum Standards)C-PI-270(1)"Welding of Transportation Pipelines"C-PI-370(1)"Transportation Pipelines-Pressure Testing"D-PI-110"Pipeline Surveys"D-TP-712 "Combined Marker and Test Point and Bond Box Details"E-PI-140"Onshore Transportation Pipelines"M-PI-190(2)"Material and equipment for Line pipe"M-PI-150"Material Standard for Flanges and Fittings"M-PI-130"Material and Equipment standard for pig Launching and Receiving Traps"M-TP-750"Material and Equipment Standard for Cathodic Protection" E-TP-820"Engineering standard for electrochemical protection"E-GN-100"Engineering Standards for Units"M-PI-150"Material Standard for Flanges and Fittings"IGS (Iranian Gas Standards)C-SF-015" "C-PL-100 " : "M-TP-010"3 Layer Polyethylene & Associated Coating System"M-PL-027"Anchor Flanges"M-PL-006"Insulating Joints"M-PL-025"Geotextile Fabric"M-TP-015"Pipeline Casing Insulators and End Seals"C-PL-013"Code of Practice for Purging of Gas Pipelines"E-PL-031"Pig Signaler System"Note:In case of conflict between the above Codes and Standards and this specification, requirements of this specification shall be followed.For all codes & standards of pipeline see contract attached - code & standard part.5- UnitsThis document is based on International System of Units (SI), unless otherwise specified.(E-GN-100 "Engineering Standards for Units")6- Design DataThe following design data is to be used for design of pipeline:Table 1 Design Data for PipelineServiceNatural Gas

Fluid CategoryD

Design CodeIGS-C-SF-015ASME SECVIIIASME B31.8

Design FactorAs per table 2 of IPS-E-PI-140

Design Pressure1050 Psig

Material Conformance to NACENo

Internal CoatingNo

External Coating3 Layer Poly Ethylene Coating

Above/Under GroundUnder

Pipeline Cover (mm)1200 normally but at crossings ACC to Crossing Drawings

Pipe MaterialAPI 5L Grade X65 (PSL2), IPS-M-PI-190(2)-API 5L

7- Design7 8 7-1 General ConsiderationsThe relevant sections of ASME and API codes and standards referred to and supplemented by this Specification shall be used for design of the pipeline in which the operating conditions and requirements, ease of inspection and maintenance, environmental conditions, safety requirements, geographic location, climatic, geotechnical and seismic conditions as well as future changes and expansions should be taken into account over the pipeline entire projected life cycle including its final abandonment.7-2 Mechanical Design6 7 7-2 7-3 General Considerations Application of Codes Pipelines carrying Natural Gas shall be designed and constructed in accordance with ASME B31.8 and IPS-E-PI-140. WeldingWelding of carbon steel pipeline shall comply with IPS-C-PI-270 (1). Pigging requirements40" Gas transmission pipeline shall be designed to have the capability of passing suitable types of pigs through them. For this line, bends should have a sufficient radius to allow passage of those types of pigs which are anticipated to pass through them. The minimum radius of bend shall be 5D (Prefabricated Hot Bend) (ASME B16.49). Permanent pig signalers should only be considered when frequent pigging operations are anticipated. Pig launcher and receiver systems for pipelines shall be designed in accordance with PROJECT specification and data sheet. Valves to be used in the pipeline which will be pigged shall be full bore ball valves. Reduced bore ball valves may be used in piping which is not to be pigged. Hydrostatic testingThe pipeline and associated piping system shall be hydrostatically tested in accordance with IPS-C-PI-370(1). Block valvesBlock valves should be provided at each end of section ACC to ASME B31.8 standard and where necessary all pipelines, at all connections and branches of the pipeline and where necessary for safety and maintenance reasons to isolate long pipelines into sections as to limit the release of line content in case of leaks or line raptures. Max distances between line break valves shall be 20 miles (approximately) for class location 1. All pipeline block valves shall be equipped with "Line Break" system. For other location class according to ASME B31.8 section 846.1. Thermal relief valvesThermal relief valves should be considered for each pig traps. Vents and drainsVent and drain connections should be provided where necessary for satisfactory testing & commissioning. Valves and flangesThe rating of valves should be adequate for design pressures of the pipeline subject to ASME B16.5 & ASME B16.47 SERIES-A pressure and temperature limitations. The number of flanges in the pipeline and piping systems should be kept to a minimum and should be installed only to facilitate maintenance and inspection and where construction conditions or process requirements dictate. Tie-in welds are preferred. Double block and bleed systemDouble block and bleed system should be used in the situations where isolation of the main stream from the ancillary equipment is needed for safe operation and maintenance without depressurizing the pipeline.This system is used for Line Break Valve in LBV Stations. Pipeline stabilitySections of the pipelines in swamps, floodable areas, high water table areas, river crossings, etc. shall be stable under the combined action of hydrostatic and hydrodynamic forces. The negative buoyancy should be sufficient to prevent unacceptable lateral and vertical movements and displacement of the pipeline. One or a combination of the following methods can be employed to achieve on-bottom stability: Applying concrete coating Installing Geotextile sheetsThe pipeline should be stable while empty or filled with water (for test) or with gas for which it is designed. When calculating the negative buoyancy the density of water-logged backfill mud should be taken into account.Special consideration shall be given to possible differential settlements in weak soils which may cause damage to the pipeline. Pipeline wall thickness calculating basisThe nominal pipe wall thickness shall be calculated according to IPS-E-PI-140 & ASME B31.8 for natural gas. Special attention shall be paid to the requirements given in the above mentioned standard for the least wall thickness of the pipe when the ratio of pipe nominal diameter to wall thickness exceeds 96. Design factors (for hoop stress limitation)The recommended design factors shall be according to IPS-E-PI-140 Para 7.5.2.2. Corrosion allowanceBecause of this line pipe is carrying natural sweet gas, No corrosion allowance shall be considered in calculating pipe wall thickness. SoftwareFor stress analysis calculation use CAESAR II software8- Materials7 8 8-1 Line pipe MaterialsCarbon steel line pipe shall be in accordance with API Spec. 5L supplemented by IPS-M-PI-190(2).Line Pipe shall be in accordance with API-5L-SAW-GR.X65-PSL2. Spiral welded pipes can be used for flat areas. It is strongly recommended "not to use spiral welded pipes for field bending". In case of emergency, prior approval of authorizes site engineer shall be taken.8-2 ValvesValves should comply with IGS-MS-PL-010 (PART1&2&3), API 6D and PROJECT specification. The valve inlet and outlet passages should be specified to match the pipe internal diameter.8-3 Branch Connections, Fittings, etc.Flanges and fittings shall comply with IPS-M-PI-150& IGS-MS-PL-022 PART1&2 and PROJECT specification. Threaded connections (pipe to pipe, fittings, etc.) and slip-on flanges shall not be used in any part of the pipeline system."Pup" pieces should not be less than 1 pipe diameter. Flanges should preferably be of welding neck type and the neck should match the internal diameter of the line pipe for welding.Flange materials are compatible with pipe material according to ASME B16.5 for NPS up to 24" and ASME B16.47 Series A shall be used for NPS 24 and larger. Flanged connections shall conform to the followings: Raised face, serrated finish flanges for classes 600 and below.9- Pipeline Route Selection8 9 9-1 GeneralIn selecting the route, full account shall be taken of the associated risks (particularly safety and environmental risks based on location classes, fluid categories, expected frequency of failure, etc.), the accessibility for maintenance and inspection, as well as economic factors (length of line, difficult terrains and crossings, etc.).Site checks of alternative routes should be made and available maps and geotechnical/geological information should be studied before selecting a suitable route for detailed survey.9-2 Route and Soil SurveysDetailed survey data should be made available before finalizing the pipeline route and carrying out detailed design. These data shall comply with those indicated in IPS-D-PI-110. Additional plan and profile drawings at enlarged scale (1/10000) should be provided for difficult sections such as crossings at rivers, roads, railways, etc. Additional data to be furnished as follows:a) Geotechnical and other environmental data (such as landslides, faults, earthquakes, floods, currents at river crossings, climatic data, vegetation, fauna, etc.).b) Soil investigation for type and consolidation of ground for assessing the degree of excavation difficulties.c) Soil investigation for foundation design (burial and/or support design), subsidence areas (e.g. underground erosion and cavitation by acidic water or mining activities).d) Water table levels at mid spring and winter along the route of the pipeline where it is to be buried.e) Soil receptivity along the pipeline route for coating selection and cathodic protection design. Areas where soil properties may change due to causes such as Sulphide reducing bacteria, which increases current required for cathodic protection systems, should be identified.f) Pipe line crossing standard typical drawings are according to project standard typical drawings.9-3 Proximity to Occupied BuildingsFor minimum distance of pipeline from occupied buildings, reference shall be made to the "Right of Way Committee of NIGC" regulations. (According to C-Sf-015)9-4 Proximity to Other FacilitiesFor minimum distance of pipeline from other facilities such as industrial sites, high tension power lines reference shall be made to the "Right of Way Committee of NIGC" regulations (According to C-Sf-015).9-5 Right-of-WayEvery pipeline shall have a permanent right-of-way with sufficient width to enable the line to be constructed (including future additional lines) and to allow access for pipeline inspection and maintenance.Land acquisition drawings shall be prepared and necessary coordination with related authorities shall be made.Pipe line right of way standard typical drawings are according to 40RSN-00-BD-PL-DWG-2014-A0 (Typical Dwg. For Pipeline Right Of Way)8 9 9-5 9.5.1. Right-of-way widthFor every pipeline PROJECT, the width of the right-of-way should be decided based on the following criteria: Diameter of the pipeline. Method of construction. Pipeline being in flat areas or in mountainous or hilly areas, etc. Future pipelines along the same route (particularly in hilly and mountainous areas where blasting and/or excavation for widening the existing right-of-way may create problem). Type of fluid and pressure of the pipeline and the consequential risks of pipeline failure.For buried natural gas pipeline, widths of right-of-way shall conform to "Right of Way Committee of NIGC" regulations. (According to C-SF-015)Pipe line right of way standard typical drawings are according to 40RSN-00-BD-PL-DWG-2014-A0 (Typical Dwg. For Pipeline Right Of Way)9.5.2. Other considerationsThe longitudinal slope of right-of-way should not exceed 22%. However, for short distances (less than 1 km), the longitudinal slope of the right-of-way may be up to 30% in which case the service roads with maximum longitudinal slope of 22% should be considered for access to these sections. In high longitudinal slope and depending on depth of trench coverage and type of soil and seasonal inundation where pipeline may lose its full restraint, it should be ensured that the equivalent stresses in the pipe wall are within acceptable limits or else remedial provisions are considered to reduce or eliminate longitudinal forces due to effective component of the dead weight of the pipeline and its content.10- Pipeline Protection and marking9 10 10-1 Trench DimensionsMinimum covers requirement shall be according to ASME B 31.8 Para 841.142.Notes:1) The cover refers to the undisturbed ground level to the top of the pipe.2) Additional depth may be required in certain locations such as agricultural areas where depth of ploughing and of drain systems shall be taken into account. A cover of 1.2 m would be adequate in most cases. The width of trench should be not less than 400 mm wider than the pipeline outside diameter in all ground conditions including rock.When pipelines are coated the outside diameter of coated pipe should be assumed as outside diameter for minimum coverage.10-2 Thermal Expansion and Other ForcesPipeline anchors should be installed at end points of buried pipelines and at other locations where the pipeline rises above ground level for connections to facilities, etc. ACC to IGS-M-PL-027.Pipeline anchors should be designed for the particular application to withstand forces due to temperature variations and to suit the ground conditions specially where subject to seasonal inundation or in dry water courses in high slopes where pipeline dead weight creates longitudinal stresses.10-3 Corrosion ProtectionAll metallic buried pipelines shall be coated externally by a suitable anti-corrosion coating, supplemented by cathodic protection and electrically isolated from the plants and facilities to which they are connected.The design of cathodic protection systems shall be carried out in accordance with IPS-E-TP-820, IGS-M-PL-006 and PROJECT specification and calculations.For this PROJECT, 3 layer polyethylene coating has been selected as anti-corrosion coating. For field joint coating, heat shrinkable sleeve has been selected.10-4 Pipeline MarkersThe location of buried pipelines shall be clearly identified by markers. In areas where the risk of interference or disturbance by mechanical excavators or boat anchors (at river crossings) is high, additional warning signs should be installed to lower the risk. Pipeline markers should be installed at the following locations along buried pipelines:a) At one kilometer interval. b) At all major changes in direction of the pipeline. c) At both sides of every road, railway and under-water crossings. d) At changes in wall thickness or material. e) At branches. f) At buried valves and fittings such as check valves, vents, drains, slug-catchers, etc. 11- Crossings10 11 11-1 River CrossingsWhere pipeline has to cross a major river, careful studies shall be carried out as to determine the most suitable way of crossing which will ensure maximum reliability during the pipeline operating life with minimum maintenance problems. The selection of the most suitable location and type of crossing should be based on the survey results and information on geotechnical and hydro climatologically conditions and other prevailing environmental issues. The migration of the river course should also receive particular attention.The sections of pipelines laid under the river bed should be concrete coated.The sections of pipeline laid in trenches in the river bed should be concrete coated to give the necessary negative buoyancy to the pipeline to fully restrain the pipeline in position at all times, during construction, operation and while shut down for maintenance or inspection. The weight coating should normally be designed to maintain pipeline stability in mud of specific gravity. In any case, the nature of the river bed should be taken into account in determination of required weight.11-2 Road and Railway CrossingsPipelines crossing roads and railways should preferably be through culverts or concrete box and bridges (new or existing). The use of casing pipe should be discouraged (due to external corrosion problems and electrical contact between casing pipe and carrier pipe). (See API RP 1102 for recommendations in this respect.) Suitable protection should be provided on both sides of the road to prevent damage to the pipeline by vehicles leaving the road. For selecting size and wall thickness of pipe casing relevant calculations shall be carried out during detail design stage. In case of using casing pipe for pipe protection under asphalt road, suitable insulators and centering cradles and casing end seal should be used. Method of crossing and detail of it shall be as per PROJECT standard drawings.If the right-of-way is intended for more than one pipeline, culverts or bridge should be wide enough to accommodate future pipeline(s). In this case the horizontal space between two adjacent pipelines should not be less than 400 mm11-3 Crossing Other Pipelines:Where a buried pipeline is to cross an existing above-ground pipeline an increased depth of cover should be specified for the whole width of the right-of-way.Where a buried pipeline is to cross an existing buried pipeline the new line should pass under the existing line with at least 900 mm clearance between the two lines.Potential test points, current test points and bonding points (direct or resistance) should be installed on both lines at the crossing to enable the Cathodic protection systems to be interconnected, if required.Where a pipeline crosses an existing pipeline owned by an outside Company, the design of the crossing and cathodic protection should satisfy the requirements of the outside Company.11-4 Crossing Land FaultsWhen pipeline has to cross a passive fault, the necessity of provision of any protection system should be decided after geotechnical survey results are studied by geotechnical sub-contractor and their recommendations are given. Crossing an active fault shall be avoided if feasible. When, however, pipeline has to cross an active fault or a passive fault which is expected to become active, the following considerations should be given at the crossing for the protection of the pipeline.Design factors similar to those indicated for rivers, dunes and beaches should be used for 300m on either side.Crossing angle should be selected for minimum bending and shear stresses in the pipeline wall due to movement of the fault banks.There should be no horizontal bends, flanges, tees, valves or similar constraints such as concrete weights in at least 200 meters of the pipeline either sides of the fault center.The trench dimensions and the backfill material around the pipeline at 200 meters either sides of the fault center should be selected in such a way that the pipeline is subjected to minimum restraint.Line break valves with automatic shut-down operators shall be installed at 250 meters either side of the fault center. These valves should be secured against movements of the section of the pipeline which crosses the fault by means of adequately designed anchors.11-5 Land SlidesPassing near the areas where there is evidence of land slide shall be avoided by using alternative routes or going around the suspected areas.12- environmentalThe pipeline shall be designed with considering all of EIA study limitation.