Abstract
A standard one-piece firefighter proximity suit (jumpsuit style) was tested for heat accumulation and hood compartment ventilation. Large increases in temperature of the skin and hood compartmental air were recorded. Oxygen and carbon dioxide were monitored and hypoxic conditions found. Using the O2 and CO2 data, mathematical regression analyses were performed to predict the time exposures allowed for firemen entering various ambient atmospheric conditions. The short permissible exposure periods predicted for the proximity suit suggests limited usefulness and the need for immediate improvements in the design of the suit.