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
Keywords: ISO 11114-5, plastic liners, gas cylinders, test methods, permeation test, swelling blistering, liner collapse, Type 5 cylinders, compatibility testing.
Open preview (PDF)Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 5: Test methods for evaluating plastic liners