Document kDrnbXdnQdoLmXLgjV9vkx14D

230 CHAPTER 12 ' \ 1916 Guide 231 rooni itself and objects within the room, including windows, heating and cooling equipment, and other occupants, has an important bearing, on the feeling of warmth and may alter to some measurable degree the optimum conditions for comfort previously indicated. Fig. 7 29 shows the elevation in the dry-bulb temperature of the air necessary to compensate for the lower temperature ofcthree of four side-wall surfaces, and indicates that for this condition each degree reduction in the average of the three wail surface temperatures requires an elevation of 0.3 deg in the dry-bulb temperature of the air. Studies by the A.S.H.V.E. Research Laboratory 28 .on the effect of radiation within an enclosure, including the effect of panel heatingT indicate that each degree elevation or depression of the mean ' Fig. 6. A.S.H.V.E. Comfort Chart for Still Air Note.---Both summer and winter comfort zones apply to inhabitants of the United States only. Applica tion 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 con-' ditionsT 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 Pitmburgh and to other cities in the northern -portion of the United Stated 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. ' people uncomfortable would not be acceptable. Systems should be designed to assure comfort for the maximum possible number. The results of recent tests 25 made at the A.S.H.V.E. Research Labora- tory in very hot conditions with subjects doing light work.were'in very close agreement with the effective temperature chart. Other recent work21 under similar environmental conditions, but with subjects walking 3. mph and carrying 20 lb packs indicated that the effective temperature lines should be more nearly, horizontal. It therefore appears that the slope of the ET lines may vary depending upon the rate of work being per formed. " Radiation between the occupant of an enclosure and the surfaces.of the ;. L, Fig. 7. Cooling Effect of Three Cold Walls in a Small Experimental Room, as Determined by Comparison with Sensations in a Room of Uniform , Wall and Air Temperature radiant temperature above or below the air temperature requires about 0.5 deg counterchange in effective temperature of the air. Since the mean radiant temperature of a space is affected by cold walls and win dows, as well as by the warm surfaces of heating units placed within the room or imbedded in the walls, these factors must. be compensated. Likewise, in densely occupied spaces, such as classrooms, 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. ''More recent tests25 made at the A.S.H.V.E. Research Laboratory indicate that for high effective temperatures the correction in ET neces sary per degree rise in mean radiant temperature is'not a constant, but varies with the values of effective temperature and mean radiant tem perature. At effective temperatures near the upper limit of human endurance, the' effect of radiant heat is very small. Additional studies on the physiological effects of radiant heating are contemplated. ' -