# NACE MR0175 / ISO 15156 Sour Service Compliance Checklist > Source: https://netray.co/tools/nace-mr0175-iso-15156-sour-service-checklist > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Checklist for verifying equipment meets sour (H2S) service material requirements: service conditions, hardness, welds, bolting and records. ## Category compliance-legal ## Industry Oil and Gas Equipment ## Audience - Materials engineer - Quality engineer - Supplier quality - Buyer ## Tool **Kind:** checklist **Scoring Note:** Any failed critical item means the component is not shown to be suitable for sour service. Hold it and ask a materials engineer to review. **Groups:** #### Service conditions **Items:** **Text:** H2S partial pressure, total pressure, pH, chlorides and temperature are stated in the specification **Critical:** true **Text:** Service is checked against the threshold for sour service defined in the standard (H2S partial pressure above about 0.3 kPa, or 0.05 psia, in wet gas) **Critical:** true Applicable environmental severity region or regime is identified for carbon and low alloy steel Presence of elemental sulfur, oxygen and other contaminants is recorded **Text:** Edition of ISO 15156 or NACE MR0175 required by the customer is identified **Critical:** true Maximum design and operating temperature limits for the material are stated #### Material selection **Items:** **Text:** Material grade is listed as acceptable in the relevant part of ISO 15156 for the stated conditions **Critical:** true **Text:** Carbon and low alloy steel pressure parts meet the hardness limit, commonly 22 HRC maximum **Critical:** true **Text:** Corrosion resistant alloys, such as austenitic or duplex stainless, are checked against their environmental limits **Critical:** true Cold worked or heat treated condition is as the standard permits Free machining grades are excluded Cast iron and certain other materials not permitted for pressure parts are excluded #### Bolting **Items:** **Text:** Studs and nuts grade is acceptable for sour service, for example A193 B7M with A194 2HM **Critical:** true **Text:** Bolting hardness is verified and within limits **Critical:** true Coating or plating on bolting is allowed by the specification External exposure of bolts to H2S is assessed (exposed versus protected) #### Welding and fabrication **Items:** **Text:** Welding procedure qualification includes hardness testing of the weld and heat affected zone **Critical:** true **Text:** Weld and HAZ hardness is within the limit permitted for the base material **Critical:** true Post weld heat treatment is performed where required and recorded Weld repairs follow the qualified procedure and are re-tested Cold forming and straightening are checked against the permitted degree of cold work #### Documentation and verification **Items:** **Text:** Material test reports show heat treatment, strength and hardness for each pressure part **Critical:** true Hardness test locations and methods follow the acceptable practice Product marking shows the sour service designation required by the customer **Text:** Compliance statement for NACE MR0175 / ISO 15156 is signed and references the edition **Critical:** true Sub supplier and casting or forging sources are covered by the same requirement Documentation is retained with the equipment data book ## Content **Intro:** Sour service means hydrogen sulfide is present, and some steels crack in it. NACE MR0175 / ISO 15156 sets material requirements to prevent sulfide stress cracking and related damage. This checklist supports a pre-order and incoming review. **Sections:** #### How to use the checklist **Body:** Start with the customer's service data: H2S partial pressure, pH, chlorides, temperature. Then check each component, from body forging to studs. For each, confirm the material is allowed in the standard for those conditions, verify hardness, and make sure the paperwork says so. Export the result and attach it to the purchase order file or supplier audit. **Bullets:** - Get written service conditions from the customer - Name the standard edition in the PO - Do not rely on a general statement from the supplier - Include bolting, springs and internals #### What the standard is **Body:** ISO 15156, published jointly with NACE as MR0175, has three parts: general principles, carbon and low alloy steels, and corrosion resistant alloys. It addresses sulfide stress cracking, hydrogen induced cracking, stress oriented hydrogen induced cracking and related forms. NACE MR0103 is a separate standard for refinery and downstream environments and should not be confused with the upstream standard. #### Key practical limits **Body:** For carbon and low alloy steel, the commonly cited maximum hardness is 22 HRC, and welds must be qualified to show hardness stays inside the limit. Carbon steel bolting often moves to B7M and 2HM to meet it. Austenitic and duplex stainless, nickel alloys and others each have their own limits on temperature, H2S level and chlorides, so they need an individual check. #### Common mistakes **Body:** Typical mistakes include accepting a stainless grade without checking chlorides and temperature, assuming standard B7 studs are fine, skipping HAZ hardness testing, and mixing up NACE MR0175 with MR0103. Poor documentation is just as common, a certificate that says compliant without edition or without hardness values. **Bullets:** - B7 bolting is not B7M - Check each sub-supplier part - Record hardness values, not just a pass - Re-check when conditions change **Cta:** Netray can help flag sour-service lines and required documentation automatically on purchase orders in your ERP. The checklist works without that. **Faq:** #### What is NACE MR0175 / ISO 15156? **Answer:** It is a standard that lists materials and limits for equipment used in oil and gas production environments containing hydrogen sulfide, to avoid cracking mechanisms such as sulfide stress cracking. #### What is the hardness limit for sour service steel? **Answer:** For carbon and low alloy steels the widely used limit is 22 HRC maximum, with specific rules and exceptions in the standard. Confirm the exact limit for your material in the current edition. #### Is MR0175 the same as MR0103? **Answer:** No. MR0103 addresses sour environments in refining and downstream facilities. MR0175 / ISO 15156 covers oil and gas production environments. #### Does this checklist certify compliance? **Answer:** No. It guides a review. Compliance is declared by the manufacturer against the named edition, supported by material and hardness records, and verified by your materials engineer. ## Search terms nace mr0175 checklist, iso 15156 checklist, sour service material requirements, h2s service hardness limit, nace compliance checklist, sulfide stress cracking checklist, nace mr0103 vs mr0175, sour service valve requirements --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json