STP986

    Ignition of PTFE-Lined Hoses in High-Pressure Oxygen Systems: Test Results and Considerations for Safe Design and Use

    Published: Jan 1988


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    Abstract

    Because of their flexibility and robust construction, high pressure hoses are a part of the equipment for industrial gas producers and users need to fill and to use gas cylinders. For oxygen service, a polytetrafluoroethylene (PTFE) lined hose is generally used because PTFE is one of the best ignition resisting plastic materials in oxygen. This type of hose has been used successfully in gaseous oxygen systems by the major gas producing companies for many years, but recently many incidents have been reported in Europe involving PTFE lined hose ignitions, mainly associated with oxygen distribution manifolds. In this paper we try to analyze the different causes of PTFE hose ignitions in oxygen service (oil contamination, particle effects, heat of compression, and so forth) taking into account the incident reports. Numerous tests have been carried out in L'air Liquide's laboratory (oil contamination measurements, pneumatic impact tests with oxygen, and so forth) on many hoses produced by many manufacturers from different countries. Results and types of failure have been analyzed by taking into account the effect of hose quality, particles, fittings, pressure, and temperature. It appears that ignitions reported on oxygen client manifolds are probably due to an “adiabatic compression” process, though they were at times initially attributed to particle effects (particle impact or static electricity) or to poor mechanical behavior. To prevent such incidents, solutions are proposed for medical and industrial applications.

    Keywords:

    oxygen, ignition, ignition temperature, oxygen compatibility, gaseous tests, pneumatic impact tests, particle impact, oil contamination, flexible hoses, manifolds, PTFE, stainless steels, copper alloys


    Author Information:

    Barthelemy, H
    Safety and reliability group managers, L'air Liquide, Paris,

    Vagnard, G
    Safety and reliability group managers, L'air Liquide, Paris,


    Paper ID: STP26755S

    Committee/Subcommittee: G04.01

    DOI: 10.1520/STP26755S


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