Measurements of Hypergolic Fuels' and Oxidants' Permeation through Commercial Protective Materials. Part 1. Inhibited Red Fuming Nitric Acid and Unsymmetrical Dimethylhydrazine

Protective equipment is used by Air Force and NASA personnel who participate in hypergolic propellant transfer and loading operations that entail potential exposure to hypergolic vapor or liquid. Forty materials sections of protective suits, gloves, boots and a hood window that are now used or are under consideration for future use in hypergolic propellant transfer operations were tested to determine their resistance to permeation by the fuel, unsymmetrical dimethylhydrazine HDMH, after exposure to liquid UDMH, and their relative resistance to permeation by nitrogen dioxide N02 after exposure to the liquid oxidant, inhibited red fuming nitric acid IRFNA. The material sections were clamped in a static test cell that permitted the fabric to be exposed to the fuel or oxidant on one side while UDMH or N02 permeation was monitored by an electrochemical analyzer on the other side. The experiments were discontinued after 90 min if no permeation was detected. A new material section was used in each test the test section was neither preconditioned nor was exposure repeated. Only one suit fabric of the nine resisted both N02 and UDMH permeation for the full 90 min of the tests. One resisted both N02 and UDMH permeation for the full 90 min of the tests. One resisted UDMH for 90 min and was permeated rapidly in 2 min by N02, two resisted UDMH and N02 permeation from 20 to 30 min, and others were permeated in less than 5 min by both propellants.