Overview
ISO/TR 13086-1:2011 - "Gas cylinders - Guidance for design of composite cylinders - Part 1" provides technical guidance for designing fibre-reinforced composite gas cylinders with emphasis on stress rupture reliability and burst ratios related to test pressure. The Technical Report consolidates field experience, test-program results, and calculation/verification approaches to support development and revision of standards for composite pressurized cylinders.
Key topics and technical requirements
- Definitions and concepts
- Stress rupture: time-dependent fibre failure under sustained tensile load.
- Stress ratio: minimum fibre strength (from burst testing) divided by fibre stress at working pressure.
- Burst ratio: ratio of minimum required burst pressure to working pressure.
- Material scope
- Guidance covers common reinforcement fibres: glass, aramid, and carbon, noting their different stress-rupture behaviors.
- Recommended stress ratios
- Tabled stress ratios intended to achieve a reliability of 0.999999 over the cylinder lifetime (typical examples from the report):
- Glass: Type 2 - 2.65; Type 3 & 4 - 3.50
- Aramid: Type 2 - 2.25; Type 3 & 4 - 3.00
- Carbon: Type 2, 3 & 4 - 2.25
- Analysis and verification
- Stresses can be determined by finite element analysis or closed-form methods accounting for material non-linearities.
- Strain verification using strain gauges (see ISO 11439:2000 Annex G) and Annex A guidance for verifying stress ratios.
- Test programs and reliability
- Summarizes stress rupture test programs and explains how differing fibre chemistry and construction affect lifetime under load.
- Notes the influence of temperature (resin glass transition), environmental exposure, and resin properties on stress rupture.
Applications and users
ISO/TR 13086-1:2011 is practical for:
- Cylinder designers and structural engineers developing composite pressure vessels
- Manufacturers of Type 2/3/4 gas cylinders (breathing air, CNG, hydrogen, vehicle tanks)
- Test laboratories and certification bodies verifying burst and stress-rupture performance
- Standards committees and regulators harmonizing safety factors and test methods
- Materials engineers assessing fibre/resin choices for long-term reliability
Practical value: use this guidance to select appropriate stress ratios, design for load-sharing liners, plan stress-rupture test programs, and verify strain and burst behavior for safe, durable composite cylinders.
Related standards
- ISO 11439 (verification/strain gages)
- ISO/TS 15869, ECE R-110, ANSI/CSA NGV2 and other cylinder standards referenced in the report
- ISO 10286 (terminology used in the document)
Keywords: ISO/TR 13086-1:2011, composite cylinders, stress rupture, burst ratio, test pressure, gas cylinders, glass fibre, aramid, carbon fibre, stress ratio, cylinder design.