306 



TEMPERATURE AND HUMIDITY 



the total insulation of the clothed man has 

 been analyzed by Burton (8). 



The mitten illustration emphasizes the 

 diflficulties which are met in trying to pro- 



greatly in excess of what is practically pos- 

 sible if the hand is to remain functionally 

 useful. If the time of exposure is limited to 

 two to three hours, protection may be pro- 



IMET, 



3 MET. 



INSULATION OF 



THE TISSUES 



0.I5-K).8 CLO. 



INSULATION 

 OF THE 

 CLOTHES 

 -4 CLO. 



INSULATION OF 

 THE AIR 

 0.8— 0.2 



(f) <s> 



6 MET. 6 MET. 



HOW MANY CLO. UNITS NEEDED ? 



BROKEN UNES— 3.0CLa •_ 

 iO r 



ANY EXPOSURE^ AT REST 

 6 MOUR EXPOSURE^ AT REST 



^ 



BEST POSSIBLE MITTEN^ GOOD FOR 



2-3 HOURS^AT REST 



12 3 4 HOURS 



FALL OF BODY TEMPERATURES IN FLYING 

 CLOTHING OF 2 TO 2.5 CLO. AT 0* TO 10* F 



STRENUOUS EXERCISE, NO MITTEN NEEDE D 

 '^RELATIVE SIZE OF MITTENS NEEDED FOR' 

 DIFFERENT EXPOSURE TIMES AT -ZO^F 



Fig. 11. Graphic illustration of the interdependence of level of heat production, grade of insulation, 



and severity of exposure on the adequacy of protective clothing 



(Redrawn from A. C. Burton, 8) 



vide adequate insulation for the hands at 

 an environmental temperature of — 20°F 

 ( — 28.9°C). With this exposure, at rest, the 

 amount of insulation required by the hand is 



vided with gloves whose bullc is within prac- 

 tical limits. Finally, if exercise is strenuous, 

 the glove may be dispensed with. The mit- 

 ten illustration and the graph in the lower 



