Overview - ISO 11118:2025 at a glance
ISO 11118:2025, "Gas cylinders - Non-refillable metallic gas cylinders - Specification and test methods," defines requirements for the design, materials, manufacture and testing of non-refillable metallic gas cylinders (welded, brazed or seamless) used for compressed and liquefied gases. The third edition updates and consolidates requirements for materials, sealing devices, manufacturing controls, prototype and batch testing, marking and certification. It is written to be suitable for reference in the UN Model Regulations and to support safe, compliant production and use of disposable gas cylinders.
Keywords: ISO 11118:2025, non-refillable metallic gas cylinders, specification and test methods, gas cylinder safety, sealing devices, compressed gases, liquefied gases
Key topics and technical requirements
- Scope and applicability
- Applies to non-refillable metallic cylinders where:
- test pressure ≤ 250 bar (liquefied gases) and ≤ 450 bar (compressed gases); or
- p · V ≤ 1 000 bar·litres; or
- if p > 45 bar, then water capacity V ≤ 5 l.
- Materials
- Standards for carbon and low-alloy steels, aluminium and aluminium alloys, and austenitic stainless steels; includes chemical composition and resistance requirements.
- Design and construction
- Rules for pressure-containing parts, minimum shell wall thickness verification, drawings and workmanship for welded, brazed or seamless construction.
- Sealing devices
- Requirements and prototype tests for non-refillable sealing devices (Annex A normative).
- Inspection and testing
- Prototype tests: material, tensile, burst, drop, valve-to-cylinder interface, dimensional checks.
- Batch tests and tests on every cylinder: inspection, proof pressure test, leak testing, rejection and repair criteria.
- Conformity and marking
- Type approval procedures, certificates of conformance, required manufacturing and operational markings.
- Notable updates (third edition)
- Updated normative references; minimum shell thickness verification added; simplified wall thickness calculation (fixed F factor); revised welding qualification and valve sampling/testing; clarified UN-based marking requirements.
Practical applications - who uses ISO 11118:2025
- Cylinder manufacturers (design, production, QA)
- Testing and certification laboratories (type approval, batch testing)
- Regulators and transport authorities (safety compliance, enforcement)
- Gas producers and suppliers (selection and procurement of non-refillable cylinders)
- Conformity assessors and auditors ensuring compliance with UN Model Regulations
Related standards
- ISO 7866 (refillable aluminium cylinders)
- ISO 9809 (refillable seamless steel cylinders)
- ISO 4706 (refillable welded steel cylinders)
- UN Model Regulations (transport and marking alignment)
ISO 11118:2025 helps ensure consistent safety, manufacturability and regulatory compliance for non-refillable metallic gas cylinders used across industrial, medical and consumer applications.