What material should a check valve for Hydrogen Sulphide (H₂S - Sour Gas) be?

NACE MR0175 qualified WCB (hardness controlled) (Excellent): Mandatory - Brinell hardness ≤200 HBW, Rockwell C ≤22 HRC, CE ≤0.43 per NACE MR0175. Inconel 625 (UNS N06625) (Excellent): Excellent SSC resistance; used for valve trim and high-alloy applications. SS 316L (Good): Acceptable for most H₂S service; use low-carbon grades, verify with NACE MR0175 SSC zone. Duplex 2205 (Good): Restricted to solution-annealed condition, max hardness per NACE MR0175 Table D.1.

Hydrogen Sulphide (H₂S - Sour Gas) service

Service Selection

Check Valves for Hydrogen Sulphide (H₂S - Sour Gas) Service

Which check valves configuration suits Hydrogen Sulphide (H₂S - Sour Gas) (H₂S), in which material, to which standard — from real service data, with the pitfalls flagged.

Which check valves for Hydrogen Sulphide (H₂S - Sour Gas)?

Check Valve (dual plate, NACE MR0175) - Compressor and pump protection in sour service Typical service window: 1–700 barg (wellhead to processing), Ambient to +300°C (Claus SRU).

Recommended Configurations

Check Valve (dual plate, NACE MR0175)

Compressor and pump protection in sour service

Body Material for Hydrogen Sulphide (H₂S - Sour Gas)

Rated from real compatibility data - click any material for the full decision page.

NACE MR0175 qualified WCB (hardness controlled)Mandatory - Brinell hardness ≤200 HBW, Rockwell C ≤22 HRC, CE ≤0.43 per NACE MR0175.Excellent Inconel 625 (UNS N06625)Excellent SSC resistance; used for valve trim and high-alloy applications.Excellent SS 316LAcceptable for most H₂S service; use low-carbon grades, verify with NACE MR0175 SSC zone.Good Duplex 2205Restricted to solution-annealed condition, max hardness per NACE MR0175 Table D.1.Good Standard carbon steel (uncontrolled hardness)SSC failure risk - mandatory to verify NACE compliance.Not Recommended

Governing Standards for Hydrogen Sulphide (H₂S - Sour Gas) Service

NACE MR0175 / ISO 15156 API 6D (sour service)API 607 (fire-safe)NACE TM0177 (SSC testing)NACE TM0284 (HIC testing)ASME B16.34

What to Avoid in Hydrogen Sulphide (H₂S - Sour Gas) Service

Any valve with hardness >200 HBW body or >22 HRC trim without NACE MR0175 qualification
Chrome-plated stems in H₂S service - plating creates galvanic cell

Service Considerations

NACE MR0175/ISO 15156 qualification certificate required for EVERY metallic component - body, trim, bolting, springs
Hardness control: body ≤200 HBW, trim ≤250 HBW (NACE MR0175 Table A.2)
H₂S gas detection system mandatory in valve stations and processing areas
Fire-safe (API 607/6FA) valves mandatory in sour service process areas
Periodic HIC testing (TM0284) of valve body plates where sour pipelines exceed NACE limits

Other valve types for Hydrogen Sulphide (H₂S - Sour Gas)

Ball Valves for Hydrogen Sulphide (H₂S - Sour Gas)Gate Valves for Hydrogen Sulphide (H₂S - Sour Gas)Globe Valves for Hydrogen Sulphide (H₂S - Sour Gas)

Check Valves for other services

Check Valves for High-Pressure Steam Check Valves for Carbon Dioxide (CO₂)Check Valves for Diesel Fuel / Fuel Oil Check Valves for Cooling Water Check Valves for Methanol (Methyl Alcohol)Check Valves for Hot Oil (Thermal Heat Transfer Fluid)Check Valves for MEG / Glycol (Monoethylene Glycol - Gas Dehydration)Check Valves for Demineralised Water (DM Water / Deionised Water)

Reviewed by Process Engineering, Vajra Industrial SolutionsDiscipline: Process & Fluid Service EngineeringLast reviewed: 20 June 2026

Connected Engineering

Standards

API 6D NACE MR0175 API 607 Fire-Safe

Failure Modes

Stress Corrosion Cracking

Services

Hydrogen Service

Products

Check Valves

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Relevant Products

Vajra Check Valves

Engineering references

Hydrogen Sulphide (H₂S - Sour Gas) service guideFull compatibility, standards & considerations Vajra Check ValvesFull range, specs & standards Spec Check engineValidate this spec before the RFQ