THERMOREGULATORY RESPONSE TO WEARING ENCAPSULATED PROTECTIVE CLOTHINGDURING SIMULATED WORK IN VARIOUS THERMAL ENVIRONMENTS

This investigation assessed the thermoregulatory impact of performing simulated tasks normally encountered during chemical accident clean-up while wearing chemical protection clothing under various representati ve thermal loads. A Drager 500 (D) suit was worn with a self-contained breathing apparatus (SCBA) external to the suit, while both a Trelleb org Trellchem(R) Super Extra (T) and a James North MZ500 (J) suit requ ired the SCBA to be worn inside the suit. The D suit was unventilated, while the T and S suits were ventilated with the subject's exhaled ai r. The T suit also was ventilated via a 2 L/min flow of air from the S CBA. Subjects were six firefighters. Each simulation lasted for 30 min utes and involved tasks such as drum rolling, drum carrying, walking, and hose dragging. The trials were conducted at 11.3, 17.1, and 23.8-d egrees-C WBGT. The overall mean peak heart rate was 128.1 +/- 2.80 bre aths/min and was elicited while performing lifting tasks. Nonsignifica nt differences (p > 0.05) were observed for both the average heart rat e and sweat rate. Mean skin temperature, mean body temperature, and te mperature within the suit cavity were significantly higher when wearin g the D suit compared to wearing T or J suits; differences between the T and J suits were nonsignificant. Suit type did not significantly af fect rectal temperature, which also failed to exceed the American Coun cil of Governmental Industrial Hygienists' (ACGIH) standard of 38.0-de grees-C. These data illustrate that the D suit significantly retarded heat dissipation as measured by mean body temperature in comparison to the T and J suits, though not enough to differentially affect core te mperature or elevate it above the ACGIH limit.