ISO 17945:2015

Overview - ISO 17945:2015 (sulfide stress cracking / SSC)

ISO 17945:2015 specifies material requirements for resistance to sulfide stress cracking (SSC) in sour petroleum refining and related processing environments where hydrogen sulfide (H2S) is present as a gas or dissolved in an aqueous phase. It is focused on preventing SSC of metallic components (pressure vessels, heat exchangers, piping, valve bodies, pumps, compressors, etc.) used in refinery service. The standard is limited to material and fabrication controls for SSC resistance - it does not provide design specifications and excludes other wet H2S cracking modes, environmental cracking, generic corrosion, and unrelated failure mechanisms.

Key topics and technical requirements

• Scope and applicability: Applies to components exposed to sour refinery environments where SSC failure would compromise pressure containment, basic function, or restoration while containing pressure. (See Clause 6.)
• Material classifications: Requirements for ferrous and non‑ferrous materials (Chapters 13 and 14), including carbon steels, alloy steels, stainless steels (ferritic, martensitic, austenitic, duplex, highly‑alloyed), nickel alloys, titanium, aluminum, and copper alloys.
• Hardness requirements: Mandatory hardness controls to limit SSC susceptibility (Chapter 8 and Annex B).
• Fabrication and welding: Welding, overlays, cladding, and post‑fabrication controls to maintain SSC resistance (Chapter 15 and 13.x welding sections).
• Bolting, coatings, special components: Requirements for bolting, plating/coatings, bearings, springs, instrumentation parts, seal rings, and other special parts (Chapters 16–19).
• Qualification & verification: Procedures for adding new materials/processes, field experience and laboratory test data, and qualification of unlisted alloys for specific applications (Clauses 9–11).
• Informative and normative annexes: Sulfide species plot, hardness testing background, and welding procedure qualification layouts (Annexes A–C).

Practical applications

• Use ISO 17945:2015 to select and qualify metallic materials and fabrication practices for equipment operating in sour refinery environments to minimize SSC risk.
• Typical applications: pressure vessels, heat exchangers, piping systems, valve bodies, pump and compressor casings exposed to H2S-containing streams.
• Helps reduce unexpected failures, extend service life, and support material procurement and quality assurance programs.

Who should use this standard

• Refiners, equipment manufacturers, engineering contractors, and construction contractors involved in petroleum refining, petrochemical and natural gas industries.
• Materials and welding engineers specifying SSC‑resistant alloys, inspectors performing hardness and fabrication checks, and procurement teams validating supplier compliance.

Related standards and notes

• Carbon steel P‑No.1 materials per ASME BPVC Section IX are addressed by requiring compliance with NACE SP0472 as referenced by ISO 17945:2015.
• ISO 17945 complements material test standards and refinery process specifications; it is not a substitute for design codes or general corrosion standards.