STP1479

    Pneumatic Impact Ignition of Sebum Oil Film in High-Pressure Oxygen

    Published: Jan 2006


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    Abstract

    Whenever oxygen systems are assembled or maintained, a risk of introducing contamination arises. Potential contaminants include oils from a person's hands and body left behind in the form of fingerprints. The oil on the surface of skin is a complex mixture of sebum oil, lipids, sweat, and environmental materials. In high-pressure systems, heat from rapid pressurization is a high-risk ignition mechanism for the sebum contaminant. The rapid pressurization or pneumatic impact ignition of hydrocarbon-based oil contaminant in high-pressure oxygen has been widely studied. This study investigated the rapid pressurization ignition of sebum contaminant in high-pressure oxygen. The pneumatic impact ignition test of sebum contaminant was conducted according to NASA-STD-6001 Test 14. The ends of stainless steel cylindrical rods were coated with synthetic sebum at varying surface concentrations, and impacted with 27.6 MPa oxygen. The results show that there is a threshold level of sebum contaminant for ignition by rapid pressurization. The level of sebum contaminant that can be expected to be deposited by handling oxygen system components, an analysis on sebum oil properties and associated fire hazards, and the threshold levels of sebum contaminant required for rapid pressurization ignition in a high-pressure oxygen system are presented and discussed.

    Keywords:

    pneumatic impact, rapid pressurization ignition, sebum contaminant, adiabatic compression, high-pressure oxygen, ignition threshold, ignition probability


    Author Information:

    Tapia, SA
    Project Leader, NASA Johnson Space Center White Sands Test Facility, Las Cruces, New Mexico

    Smith, SR
    Mechanical Engineer, Honeywell Technology Solutions Inc., NASA Johnson Space Center White Sands Test Facility, Las Cruces, New Mexico

    Hshieh, F-Y
    Materials and Combustion Scientist, Honeywell Technology Solutions Inc., NASA Johnson Space Center White Sands Test Facility, Las Cruces, New Mexico

    Stoltzfus, JM
    Project Manager, NASA Johnson Space Center White Sands Test Facility, Las Cruces, New Mexico


    Paper ID: STP37637S

    Committee/Subcommittee: G04.01

    DOI: 10.1520/STP37637S


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