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Material selection and qualification for severe sour (H2S) service pipeline projects require expert knowledge, suitable methods and criteria throughout the design, material selection, manufacturing, qualification, and construction phases.

For pipeline construction and installation in severe sour service conditions, DNV has extensive experience gained over the last 20 years. This includes conducting comprehensive sour service testing of girth welds and deriving fracture resistance and fatigue crack growth rates for input into engineering critical assessment (ECA) based on DNV-RP-F108 and BS7910. ECA, using input from project-specific laboratory tests, has proven invaluable in establishing reasonable and practical flaw acceptance criteria, especially for severe sour service.

Similarly, DNV can identify materials suitable for hydrogen service and provide guidelines for material testing, qualification, and documentation. ASME B31.12 is the comprehensive code specifically applicable to piping and pipelines handling gaseous hydrogen and gaseous hydrogen mixtures. For repurposing and in-service integrity assessment of pipelines for high-pressure H2 transport, DNV has in-depth knowledge about the respective requirements of ASME B31.12 and expertise to conduct assessments according to the associated code API 579-1/ASME FFS-1 using the failure assessment diagram (FAD) approach (level 2 or 3), or other proven fracture mechanics methods as required.

For new gas fields containing high levels of H2S in combination with high CO2, carbon capture and storage (CCS) is required to safely handle and store the large tonnage of CO2 associated with gas production. The material selection and qualification of materials for CO2 pipelines and injection welds is an area where DNV has expertise and is supported by DNV-RP-F104 Design and operation of carbon dioxide pipelines.

Our expertise is especially directed towards:

  • Material selection and welding procedure studies for severe sour service
  • Material testing and qualification for high-pressure H2 and CO2 service
  • Pipe mill audits and selection for sour gas projects
  • Engineering critical assessments (ECAs) and integrity assessments based on API 579-1/ASME FFS-1 or BS7910 for welds operating in severe sour service or under high-pressure H2 environments
  • Fracture control studies for running brittle and ductile fractures in CO2 pipelines with various contaminants
  • Training of company engineers for the integrity assessment of pipelines for sour service, H2 and CCS.