Subscribe to our newsletter to receive the latest news and events from TWI:

Subscribe >
Skip to content

TWI – Our Role in Oil and Gas Industry Codes and Standards

Codes and Standards

TWI plays a key role in the development of many standards that are important to the oil and gas industry, including those covering:

  • Fitness-for-purpose: BS 7910, API 579-1/ASME FFS-1 and R6
  • Fatigue: BS 7608 and BS PD 5500
  • Fracture toughness testing: CTOD and SENT tests
  • Pipeline welding: BS 4515

Scroll down this page to see a list of the standards committees relevant to the oil and gas sector. You can also view updates from the Standards Committee here.


TWI has held the chairmanship of the British Standards Institution committee (WEE/37) responsible for the new fitness-for-purpose guide BS 7910 (replacing BS PD 6493) since the committee came into being in the 1970s. BS 7910 is the world's most widely used document for making structural integrity assessments and TWI has had a key role in its development. TWI is also active on the committees that develop and maintain API 579-1/ASME FFS-1 and R6.


Most fatigue design rules throughout the world draw heavily on TWI work - in particular, the unified rules in BS 7608, those contained in offshore design guidance, and those in the British pressure vessel code BS PD 5500.

Fracture toughness testing

The widely adopted crack tip opening displacement (CTOD) test was developed principally by TWI, which continues to contribute to the standardisation of the technique through the British Standards Institution, ASTM, CEN and ISO. TWI has also contributed to the standardisation of KIc and J testing methods, and to the development of single edge notch tension (SENT) testing (see DNV F107 and DNV F108) which is now widely used to evaluate fracture toughness of pipeline girth welds.

Pipeline welding

TWI holds the chairmanship of the British Standards committee responsible for BS 4515 (WEE/21/7) - probably the most widely recognised standard for pipeline welding apart from API 1104. This committee has recently developed a standard for the welding of duplex stainless steel pipelines. TWI also contributes to CEN and ISO work in this area.

Pressure vessels and storage tanks

TWI has contributed to both the British and new European pressure vessel standards BS PD 5500 and prEN 13445 with regards to fatigue, fracture toughness requirements, non-destructive testing (NDT) flaw assessment and welding procedures.

Rules for tanks for the storage of liquefied gases (BS 7777 and PD 7777) have drawn on crack arrest studies and engineering critical assessments carried out by TWI.

Materials selection for sour service

TWI staff participating as members of NACE (National Association of Corrosion Engineers) provide input to NACE Technical Committees, such as MR 0175 and TM 0177 relating to the specific influence of welding upon sour service performance of Carbon-Manganese, low alloy steels and corrosion resistant alloys (CRAs). TWI is also closely involved in the European Federation of Corrosion Standardisation activities in this area and parallel input via BSI Committees.

Welding steels without hydrogen cracking

TWI has contributed to the development of BS EN 1001: Parts 1 and 2, which specify the welding procedures required to avoid hydrogen cracking. BS EN 1001 is largely based on BS5135, itself developed from work carried out by TWI.

Standards committees relevant to the oil and gas sector:

BSI WEE/2 Testing of welds
  WEE/17 Metal arc welding
  WEE/21 Pipework welding
  WEE/21/7 Field welding of pipelines
  WEE/28 Inert gas welding
  WEE/36 Approval testing of procedures
  WEE/37 Acceptance levels for flaws in welds
  WEE/39 Welding consumables
  WEE/40 Health and safety in welding
  WEE/41 Friction welding
  WEE/45 Welding of stainless steels
  WEE/46 NDT of welds
  ISE/12 Structural steel
  ISE/12/WG1 Offshore steels
  ISE/73 Steels for pressure purposes
  ISE/NFE/4 Testing of metals
  ISE/NFE/8 Corrosion of metals and alloys
  PVE/1 Pressure vessels
  PVE/15 Storage tanks
  PSE/17/2 Transmission pipeline for oil and gas
  PRI/80 Welding of thermoplastics
CEN TC121 Welding (several working groups and subcommittees)
  TC54 Pressure vessels
  TC249/SC5 Welding of thermoplastic materials
  ISO TC44 Testing of welds and welding quality
  ISO TC67/SC2/WG8 Welding of pipelines
  ISO TC67/SC7/WG3 Offshore tubular structures
ISO ISO TC164/SC4 Fracture toughness testing
EFC Oil & Gas and Refinery Working Parties
NACE STG32 Oil & Gas Production - Metallurgy
  STG34 Petroleum Refining and Gas Processing
  TG299 Materials for use in H2S containing environments in oil and gas production

Full range of TWI standard activities

For more information, please email

For more information please email: