302 



TEMPERATURE AND HUMIDITY 



may^be eliminated by air conditioning equip- 

 ment able to maintain quarters well below 

 the stress conditions of Table XIII. 



It should be mentioned here that the 

 A.S.H.V.E. Effective Temperature Scale is 



proximately 27°C (81 °F). In the lower 

 comfort range, the scale likewise serves to 

 equate the equivalent sensation effects of 

 humidity and temperature for contrast situa- 

 tions in which a person passes from a moder- 



70 80 



DRY BUUB TEMPERATURE 'F 



Fig. 9. American society of heating and ventilating engineers' comfort chart for still air. Both 

 summer and winter comfort zones apply to inhabitants of United States only. Application of winter 

 comfort line is further limited to rooms heated by central station systems of the convection type. The 

 line does not apply to rooms heated by radiant methods. Application of summer comfort line is limited 

 to homes, offices, and the like, where the occupants become fully adapted to the artificial air conditions. 

 The line does not apply to theatres, department stores, and the like, where the exposure is less than three 

 hours. The optimum summer comfort line shown pertains to Pittsburgh and to the other cities in the 

 northern portion of the United States and Southern Canada, and at elevations not in excess of 1000 feet 

 above sea level. An increase of 1° ET should be made approximately per 5° reduction in north lati- 

 tude. 



(Reproduced by courtesy of the American Society of Heating and Ventilating Engineers) 



in process of being revised and extended in 

 scope at the present. It has been realized 

 for^some time that the scale provides a 

 very satisfactory index of equivalent condi- 

 tion at dry-bulb temperatures above ap- 



ate dry-bulb atmosphere to a similar tem- 

 perature at high (or lower) humidity. After 

 adaptation over a period of one to two hours, 

 however, the sensations reahzed are not in 

 complete accordance with the scale. In this 



