Service ConditionsFull Glossary

Sour Service

Fluid service containing hydrogen sulphide (H2S) at conditions that can cause sulfide stress cracking (SSC) of susceptible materials. Defined by NACE MR0175 / ISO 15156. All valve materials (body, trim, bolting, packing) must meet hardness limits and material qualifications for sour service.

Frequently Asked Questions

What is Sour Service?

Fluid service containing hydrogen sulphide (H2S) at conditions that can cause sulfide stress cracking (SSC) of susceptible materials. Defined by NACE MR0175 / ISO 15156. All valve materials (body, trim, bolting, packing) must meet hardness limits and material qualifications for sour service.

How does Sour Service affect valve material and design selection?

Fluid service containing hydrogen sulphide (H2S) at conditions that can cause sulfide stress cracking (SSC) of susceptible materials. Valve material selection must account for this service condition at every component: body, bonnet, trim (seats, disc/ball/gate, stem), packing, and bolting. Reference ASME B16.34 for pressure-temperature limits by material group, and NACE MR0175 for sour service material restrictions. Vajra Industrial Solutions provides materials-of-construction (MOC) recommendations based on your process datasheet.

Which valve certifications are required for Sour Service service?

Service-specific certifications depend on the application: fire-safe testing to API 607 for hydrocarbon service, cryogenic testing per BS 6364 for LNG service, fugitive emission certification to ISO 15848-1 for LDAR compliance, NACE MR0175 compliance for sour service, and SIL certification per IEC 61508/61511 for safety-critical applications. Vajra Industrial Solutions supplies fully certified valve packages with all required documentation.

Technical Support

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Our valve engineers can help specify the right valve for your application. Full project documentation available: MTCs, test reports, dimensional inspection, and third-party inspection coordination.