Unconditioned air ventilation inside an aircrew NBC suit during exposure to warm environments


  1. DuCharme, M.B.
Corporate Authors
Defence R&D Canada - Valcartier, Valcartier QUE (CAN)
The heat tolerance and thermal responses of aircrew were evaluated during their exposure to warm ambient conditions while dressed in two different NBC ensembles: the current Canadian Air Forces (CF) NBC charcoal coveralls and the LASA ventilated-NBC suit, with unconditioned ambient air circulated inside the suit and the helmet at 220 L/min. Six subjects were randomly exposed to five 6-hr periods of experimental conditions involving a 1-hr pre-flight simulation at room temperature, followed by a 4-hr flight simulation in 35 or 45ºC and 40% relative humidity(RH) ambient conditions, with a 1-hr post-flight simulation at room temperature. During the 4-hr flight simulation, the subjects simulated helicopter backender activities (cabin check, hoisting rescue, loading sonar buoys) in a climatic chamber. The five tested conditions were: LASA suit with air flow on at 35ºC (35FI); LASA suit with no air flow at 35ºC (35FO); LASA suit with airflow on at 45ºC (45FI); LASA suit with no air flow at 45ºC (45FO); and current NBC coveralls at 45ºC (45CU). During the test, heart rate (HR), rectal temperature (Tre), rate of increase in rectal temperature, mean skin temperature (Tsk), sweating rate, thermal comfort, rate of perceived exertion (RPE), relative humidity inside the clothing and tolerance time were measured. Tolerance time in the chamber, sweating rate and rate of increase in rectal temperature were similar for all conditions (average ± SE: 1.1 ± 0.2 hr; 0.65 ± 0.02 kg/hr; 1.

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Hyperthermia;heat stress;thermal comfort;helicopter aircrew;protective clothing
Report Number
DRDC-VALCARTIER-TR-2007-066 — Technical Report
Date of publication
01 Aug 2008
Number of Pages

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