STP1040

    Oxygen Compatibility of Pressure Regulators for Gas Cylinders

    Published: Jan 1989


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    Abstract

    Accidents are occasionally reported to occur due to violent ignition of oxygen pressure regulators on opening the gas cylinder valve.

    These ignitions can be attributed either to oil contamination, to particle impact or to “adiabatic compression” i.e. rapid pressurization of oxygen when opening the cylinder valve.

    Since oxygen regulators, like any oxygen equipment, are normally specially cleaned to remove traces of oil, greasy products and combustible materials, prevention of “oil contamination ignition” mainly consists in advising customers to avoid contamination in service. Particle impact ignitions can be avoided by using dust caps over the cylinder valve outlets during transport, in-line filters and by advising users to momentarily “crack” the cylinder valve before connecting the regulator.

    In this paper we concentrate mainly on investigating the conditions which could lead to ignition by “adiabatic compression”. Numerous tests have been carried out in L'AIR LIQUIDE's Laboratory to try to explain how such ignitions occur and how to avoid them. The influence of the materials used in the construction of regulators has been studied, i.e. non-metallic and metallic materials (including aluminum). This influence although very important, has been found to be closely related to and affected by the regulator internal design.

    Examples of solutions to prevent such ignition are reported in this paper.

    Another important aspect discussed is the influence of the testing equipment and procedure used to establish the ability of a regulator to resist adiabatic compression. There are already some national Standards in Europe (Germany, France, etc) or international Standard (ISO) which specify ignition test methods, however, it has recently been determined that they are not adequately precise or reliable. In fact, some tests carried out according to these Standards have produced different results (regulator acceptable or non-acceptable) depending on which laboratory performed the test. In this paper, we identify the important parameters which must be taken into account when performing the tests.

    Keywords:

    oxygen pressure regulators, ignition, adiabatic compression, oxygen compatibility, Standards, testing procedure, selection guide


    Author Information:

    Barthélémy, H
    L'AIR LIQUIDE Direction Technologie, Centre de Technologie et d'Expertises, Le Blanc Mesnil,

    Delode, G
    L'AIR LIQUIDE Direction Technologie, Centre de Technologie et d'Expertises, Le Blanc Mesnil,

    Vagnard, G
    L'AIR LIQUIDE Direction Technologie, Centre de Technologie et d'Expertises, Le Blanc Mesnil,


    Paper ID: STP24932S

    Committee/Subcommittee: G04.02

    DOI: 10.1520/STP24932S


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