Overview
ISO/TR 13086-2:2017 - "Gas cylinders - Guidance for design of composite cylinders - Part 2: Bonfire test issues" provides guidance on the safety and performance of composite pressure cylinders when exposed to fire. The technical report explains the phenomena that control cylinder behaviour in bonfire or engulfing-fire scenarios, summarizes existing fire-test approaches, and proposes an optimized method for qualifying cylinders that use pressure relief devices (PRDs), including thermally activated devices. It is intended to give designers and stakeholders a practical baseline understanding to operate composite cylinders safely in service.
Key Topics
- Composite materials and construction
- Typical reinforcement fibres: glass, aramid, carbon; common resins: epoxy, vinyl ester.
- Typical liners: steel, aluminium, HDPE, polyamide (PA).
- Laminate thickness typically ranges from 3.2 mm to 50 mm and affects heat transfer and time-to-failure.
- Fire behaviour and temperatures
- Fire sources vary (diesel, gasoline, natural gas, tyres, wood) and flame temperatures vary by fuel.
- Material thresholds noted in the report: aramid strength loss above ~425 °C (decompose ~500 °C), carbon oxidation ~600 °C, resin pyrolysis onset around 300 °C, glass melting ~1 725 °C; natural-gas flame temperature cited ~1 960 °C.
- Pressure relief devices (PRDs) and venting
- Role and activation behaviour of thermally and pressure-activated relief devices in preventing rupture.
- Considerations for testing cylinders with PRDs installed to represent in-service protection.
- Fire-test methods and optimization
- Review of standardized fire tests and variability between fuels and configurations.
- Proposal of an optimized test methodology using thermally activated PRDs and procedures to better replicate realistic bonfire scenarios.
- Statement of safety
- Topics operators must understand: materials, fires, PRDs, insulation, valves, venting, single vs. multiple-cylinder systems, and interactions among these.
Applications
- Design validation and safety assessment of composite gas cylinders for industrial, transport, and consumer uses.
- Development and qualification of PRDs and fire-protection systems for cylinder assemblies.
- Test laboratories and manufacturers conducting bonfire/fire exposure tests on full-scale cylinders filled with representative gases.
- Standards committees, conformity assessors, and regulatory bodies evaluating fire-safety performance and test methods.
Related standards
- Prepared by ISO/TC 58 (Gas cylinders), Subcommittee SC 3 (Cylinder design). ISO/TR 13086-2 complements other composite cylinder standards and test methods addressing mechanical, leak and pressure integrity; refer to committee publications for normative test standards and additional parts of the ISO 13086 series.
Keywords: composite cylinders, bonfire test, fire testing, pressure relief device (PRD), thermally activated relief, composite laminate, gas cylinder safety.
