Overview
ISO/TR 19811:2017 - Gas cylinders - Service life testing for cylinders and tubes of composite construction - is a technical report from ISO/TC 58/SC 3 that documents existing service life test programmes for composite cylinders and tubes used in the transport of dangerous goods (sea, air, land). The report applies to composite designs with a water capacity up to 3000 L and a design life greater than 15 years. Its purpose is to summarize national practices, compare approaches, and assess the feasibility of harmonizing service life testing or developing an ISO deliverable.
Key topics
- Scope and definitions: Clarifies terms such as design life (approved maximum years) and service life (years permitted in service).
- Two principal testing approaches:
- Approach 1: Repetition of selected destructive tests from type approval on a prescribed sample of representative cylinders; may also include non‑destructive inspections on each cylinder.
- Approach 2 (statistical): Test samples (Annex A: typically at least five cylinders) using slow burst and/or load cycle (fatigue) tests, with statistical extrapolation of degradation and defined acceptance criteria to estimate residual service life.
- Sampling and testing practices: National authorities provided varied sampling sizes, sampling intervals (e.g., tests before or after 15 years), and test types (hydraulic burst, flaw/drop tests, cyclic loading).
- Statistical criteria: Annex A outlines statistical methods - degradation curve extrapolation, minimum survival-rate targets and confidence intervals (including a unilateral 95% confidence level) - to justify extension of service life up to the design life.
- Regulatory context: Linked to the UN Recommendations on the Transport of Dangerous Goods, which require service life programmes for composite cylinders exceeding 15 years.
Applications and users
ISO/TR 19811:2017 is practical for:
- Cylinder and composite tube manufacturers designing type-approval test programmes and production surveillance.
- Competent authorities and type-approval bodies evaluating service life evidence for composite cylinder approvals.
- Testing laboratories conducting destructive and non‑destructive tests (burst, fatigue, leak testing).
- Fleet operators, gas suppliers and safety engineers assessing lifecycle safety, inspection intervals and end‑of‑life criteria for composite pressure vessels.
- Standards committees and regulators considering harmonization of service life requirements for transportable composite cylinders.
Related standards
- ISO 10286 (terminology)
- ISO 11119 series (composite cylinder design standards)
- ISO 11623 (periodic inspection and testing)
- EN 12245 and applicable national regulations referenced by member countries
ISO/TR 19811:2017 is a practical reference for understanding current national service life testing practices and the technical basis for extending composite cylinder service beyond 15 years under transport regulations.