NACE MR0175 / ISO 15156 Gate Valves
What NACE MR0175 / ISO 15156 requires for gate valves — applicability, key and testing requirements, the alternative standards, and compliant supply with full certification.
What does NACE MR0175 / ISO 15156 require for gate valves?
NACE MR0175 / ISO 15156 (Petroleum and Natural Gas Industries - Materials for Use in H₂S-Containing Environments (Sour Service), NACE International (now AMPP) / ISO) sets the design, material and testing requirements for gate valves in its scope. NACE MR0175 (now jointly published as ISO 15156) is the governing standard for material selection in equipment exposed to wet hydrogen sulphide (H₂S) - commonly called 'sour service'. It defines hardness limits, heat treatment requirements, and acceptable material grades for valve bodies, trim, and fasteners in H₂S-containing oil, gas, and water service. Non-compliance can cause sulphide stress cracking (SSC), hydrogen-induced cracking (HIC), or stress-oriented HIC, leading to catastrophic brittle fracture.
Applicable Pressure Classes
Key Requirements
- Carbon steel (A216 WCB, A105): maximum hardness 22 HRC (PWHT required for cast bodies)
- Low-alloy steels: individual hardness limits per NACE Table B.1
- Martensitic stainless (13Cr trim, stems): maximum 22 HRC for NACE service
- Austenitic SS (316L, CF3M): acceptable without restriction in most zones
- Nickel alloys (Alloy 625, C276): acceptable for most sour service without restriction
- Cold-worked SS is restricted - solution annealed condition required
- Welding and hard-facing procedures must produce surface hardness ≤22 HRC in HAZ
- Weld consumables and procedure qualification per NACE MR0175 Annex B
Testing Requirements
- Hardness testing: all valve bodies, bonnets, stems - per NACE MR0175 limits
- Charpy impact testing (where required by NACE MR0175)
- Weld hardness survey for hard-faced seats
- PWHT verification (where required)
Alternative Standards for Gate Valves
Other standards that also govern gate valves — useful for spec cross-acceptance.
Related Standards
Connected Engineering
Need NACE MR0175 / ISO 15156 gate valves?
We supply NACE MR0175 / ISO 15156-compliant gate valves with full certification — share your size, class and service for a 24-hour quote.