ISO 11114-2:2021

Overview - ISO 11114-2:2021 in brief

ISO 11114-2:2021, "Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2: Non‑metallic materials", provides guidance for selecting and evaluating non‑metallic materials used in gas cylinders, valves, tubes, pressure drums and bundles. The third edition (2021) covers composite and laminated materials, and focuses on how gases can change material and mechanical properties (chemical reactions or physical state changes). It does not cover ceramics, glasses, adhesives, basic mechanical design properties, the quality of delivered gas, nor cryogenic fluids (see ISO 21010).

Key topics and technical requirements

• Scope of compatibility assessment: Guidance for plastics, elastomers and fluid lubricants in contact with single‑component gases (data may apply to mixtures).
• Material types listed: Typical plastics (PTFE, PCTFE, PVDF, PA, PP, PE, PET, PEEK, PPS, PVC, PI, POM), elastomers (IIR, NBR, CR, FKM, VMQ, EPDM, ACM, PUR, ECO, FVMQ) and lubricants (hydrocarbon, fluorocarbon).
• Compatibility risks classified: violent reaction/oxidation (F), mass loss (W), swelling (S), change in mechanical properties (M), plus other considerations - to be assessed under normal and abnormal conditions.
• Temperature and service considerations: Effects of low/high temperature on embrittlement, softening or permeability; special caution below −50 °C and when transferring at low temperatures.
• Documentation and approval: Use of compatibility tables (Table 1) and a dedicated table for liners (Table 2). A competent person must approve materials or require testing where necessary.
• Testing and safety: For oxidizing gases, or where violent reaction is possible, perform appropriate safety tests (see ISO 11114‑3 for autogenous ignition testing and ISO 10297 for valve testing).

Practical applications

• Material selection and validation for gas cylinder manufacturers, valve designers, and composite cylinder producers.
• Risk assessment for gas suppliers, compressor/filling station operators, and transport/pressure vessel safety engineers.
• Specification of seals, O‑rings, liners and lubricants used with oxygen, fluorine, chlorine and other reactive gases.
• Reference for regulatory compliance and safe design when preparing documentation for the UN Model Regulations and transport standards.

Who should use this standard

• Design and R&D engineers for cylinders and valves
• Testing laboratories and QA teams
• Regulatory authorities and compliance officers
• Gas industry safety and procurement specialists

Related standards

• ISO 11114-1 - compatibility of metallic materials
• ISO 11114-3 - autogenous ignition test for non‑metallic materials in oxygen
• ISO 10297 - cylinder valve specification and type testing
• ISO 21010 - cryogenic compatibility (excluded from Part 2)

Keywords: ISO 11114-2:2021, gas cylinders, non‑metallic materials, material compatibility, valve seals, composite cylinders, oxygen compatibility, elastomers, plastics, lubricants, safety.