Document xzr6yg9nazXKLRnaKYRv3mRD6

228. CHAPTER 12 1949 Guide dicated. Since the mean radiant temperature of a space is affected bycold walls and windows, as well as by the warm surfaces of heathlg units placed within the room or imbedded in the walls, these factors must be compensated. Likewise, in densely occupied spaces, such as classrooms, 5physiblogica.l Principles 229 ihents of offices employing large numbers of workers (Fig. 11). On the whole women of all age groups studied prefer ah effective temperature for comfort 1.0 deg higher than men. All men and women over 40 years of age prefer a temperature 1 deg ET higher than that desired by personsp. below this age. The persons serving in all of these studies were repre sentative of office workers dressed for air conditioned spaces in the summer season and engaged in the customary office activity. On the basis of present knowledge, for different geographical regions and age groups, the most popular temperature varies from a low of 66 deg ET in winter to a high of 73 deg ET in summer. The spread for summer comfort is 69 to 73 deg ET. Note.---Both summer and winter comfort cones apply to inhabitants of the United States only. Applica tion of winter comfort line is further limited to rooms heated by oentral 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 con' ditions. The line does not apply to theaters, department stores, and the like where the exposure is less than 3 hours. The optimum summer comfort line shown pertains to Pittsburgh and to other cities in the northern portion of the United States and Southern Canada, and at elevations not in excess of 1000 ft above sea level. An increase of one deg ET should be made approximately per 5 deg reduction in north latitude. 1 theaters and auditoriums, temperatures somewhat lower than those indicated by the comfort line may be desirable because of counter radiation between the bodies of occupants in close proximity to each other. Such radiation will also elevate the mean radiant temperature of the room. . Many field studies23 have been made to determine the optimum indoor effective temperature for both winter and summer in several metropolitan districts of the United States and Canada in cooperation with the manage- The A.S.H.V.E. Technical Advisory Committee on Sensations of Comfort, ascribes a spread of 3 deg in the optimum effective-temperature for summer cooling to geographical location. However, it should be recognized that variations in sensation of comfort among individuals may be greater for any given location, as shown in Fig. 11, than variations, due to a difference in geographical, location. The available information in.dicates that changes in weather conditions over a period of a few days do not alter the optimum indoor temperature. Sudden chilling (shock) of persons entering a cooled and air conditioned space during the summer months, may at times be important. It is due to the rapid evaporation of perspiration which accumulated on the ;skin and in the clothing dining previous subjection to hot and'humid'Outside conditions. .While studies1^ have shown that'for healthy individuals this shock is not harmful under some conditions it may be unpleasant of