Background: It is important to examine the microclimate of a pilot's clothing to evaluate the heat stress the clothing imparts on a pilot, but problems arise with regard to individual variation (phenotype of the pilot, sweating dose, wear condition of the flight coveralls, etc.).
Hypothesis: The present study used a Japanese type sweating mannequin (TOM-III) to evaluate the microclimate of flight coveralls.
Methods: TOM-III (TOYOBO, Co., Ltd., Tokyo, Japan) has a characteristic Japanese human body type, and the sweat rate and body temperature can be regulated (240 g of sweat per hour, 36.0 degrees C). The microclimate of the clothing was evaluated by means of 20 temperature/humidity sensors located on the surface of the mannequin skin. TOM-III wore four different assemblies of clothing (CWU-66/P USAF chemical defense flight coverall; JASDF summer-type flight coverall which is similar to the nonchemical defense USAF flight coverall; ordinary 100% cotton underwear; and CWU-66/ P with cotton underwear). We put TOM-III in climatic chamber (21.2 +/- 0.5 degrees C, 50.0 +/- 3.0% relative humidity (RH), 0.1 m air flow x s(-1), dressed in test clothing, and measured the inside temperature (IT) and inside relative humidity (IRH) of the clothing for 60 min (10 min non-sweating, 30 min sweating and 20 min non-sweating).
Results: Approximately 5 min after the onset of sweating, the IRH of the CWU-66/P (38.0%) was lower than JASDF flight coverall (42.1%; p < 0.01). At the end of the sweating period, the IRH of the CWU-66/P and the JASDF flight coverall were 46.2% and 52.6%, respectively (p < 0.01). The results indicated that the CWU-66/P flight coverall was better suited for heat stress than the JASDF summer-type flight coverall.
Conclusions: TOM-III may be useful for microclimate evaluation and/or the development of clothing without considering individual variation against various climatic conditions.