ISO 11114-5:2022

Overview

ISO 11114-5:2022 - "Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 5: Test methods for evaluating plastic liners" specifies laboratory and cylinder-level test methods to evaluate plastic materials used as liners in composite and Type 5 gas cylinders. The standard defines how to assess gas compatibility risks (as identified in ISO 11114-2) using reproducible procedures and reporting requirements. It does not cover compatibility issues between plastic liners and certain test fluids (e.g., water).

Key technical topics and requirements

• Scope and intent
  • Focus on test methods for plastic liners and plastic matrix materials for Type 5 cylinders.
  • Designed to support material selection and validation against risks described in ISO 11114-2.
• Two test levels
  • Specimen (coupon) tests - Clause 5: used to compare materials or assess local variations.
  • Cylinder tests - Clause 6: mandatory to determine overall liner suitability in service-like geometry.
• Principal tests described
  • Permeation (permeability) test: procedures for disc samples, test cell design, detection methods (permeated volume, mass spectrometry, gas concentration in fixed volume, pressure rise) and calculation of permeability coefficient.
  • Swelling / blistering test: methods to detect localized delamination or bubbles in liner material.
  • Ageing test: procedures to evaluate changes in material properties over time.
  • Liner collapse tests: assessment when internal cylinder pressure falls below atmospheric pressure.
  • Cylinder-level permeability, collapse, and blistering evaluations with defined procedures and evaluation parameters.
• Specimen preparation and controls
  • Typical disc dimensions (external diameter 40–80 mm; exposed face ~30 mm), manufacturing/process traceability, and conditioning recommendations (e.g., dehumidify/outgas - heating to ~65 °C under vacuum until mass loss criteria).
  • Test cell components: elastomer O‑rings, wire‑mesh support (consistent contact area), sintered metal support and sealing strategies to ensure reproducible results.
• Reporting
  • Requirements for recording test-gas analysis, specimen dimensions, procedures and interpretation of results (see Clause 8).

Practical applications

• Selecting and validating plastic liner materials for composite and Type 5 gas cylinders.
• Defining acceptance/rejection criteria during R&D, production qualification and type testing.
• Informing design validation with realistic permeation, swelling and ageing performance data.
• Supporting compliance documentation for regulators, certification bodies and clients.

Who should use this standard

• Cylinder manufacturers and composite liner fabricators
• Materials and polymer engineers
• Accredited testing laboratories and quality assurance teams
• Design engineers and conformity assessment bodies
• Regulatory authorities and procurement specialists

Related standards

• ISO 11114-2 (compatibility risk considerations)
• Design standards referenced for complementary requirements (e.g., ISO 11515, EN 12245)
• Plastic test standards cited (ISO 178, ISO 527, ISO 3167, etc.)

Keywords: ISO 11114-5, plastic liners, gas cylinders, test methods, permeation test, swelling blistering, liner collapse, Type 5 cylinders, compatibility testing.