An evaluation program was undertaken to choose new materials for NASA's propellant handlers' ensemble (PHE) used in the operations involving the transfer of hypergolic fuels and other hazardous chemicals. NASA currently uses an encapsulating suit constructed of a chlorobutyl rubber/Nomex® material in conjunction with a liquid air self-contained breathing apparatus (SCBA). The inventory of 300 suits and SCBAs are subjected to approximately 8000 wearings per year, and require an extensive maintenance and recycling program to ensure their continued effectiveness.
A review of existing NASA suit requirements and applications indicated a number of parameters important in the selection of the suit materials and seam construction. Other ensemble clothing items such as visors, gloves, boots, and suit closure systems were also considered. Performance criteria were developed based on existing NASA specifications and requirements in the National Fire Protection Association standard on vapor-protective suits (NFPA 1991). A life cycle cost analysis of the suits provided the range of material/suit costs based on expected service life. This information was used to develop a new specification that was submitted to industry for soliciting material candidates.
Baseline performance data were generated for the existing chlorobutyl rubber/Nomex material and related suit materials. A rating system was developed to assist selection and testing of replacement materials.