Document 60XGavjNB6VxoRQqyLjOK79

American Society of Heating and Ventilating Engineers Guide, Table 2. Condition of Sensible Perspiration for Persons Seated at for Various Atmospheric Conditions'* 41 Atmospheric Condition DEGREE Of PERSPIRATION 95 PER CENT R. H. 20 PER cun R ^ Forehead clammy.......................................... .Body clammy...... .......................................... Body damp......... ......... .................................. Beads on forehead.............................. .......... . Body wet................ ........................................ Perspiration on forehead runs and drips.. Perspiration runs down body......... .......... E. T. 73.0 73.0 79.0 80.0 84.5 88.0 88.5 D. B. 73.6 73.6 79.7 80.8 85.4 89.0 89.5 W. B. 72.4 72.4 78.4 79.4 84.0 87.6 88.1 75.0 75.0 81.0 87.0 86.5 94.0 90.0 87.0 87.0 97.5 109.4 108.5 125.2 116.0 Forty per cent of subjects registered degree of perspiration equal to or greater'than indicated? " b" Thermal Exchanges between the Human Body and its Atmospheric Environment," by F. C Hnnnu W. W. Teague, W. E. Miller, W. P. Yant {American Journal Physiology, Vol. 88, No. 3, April/iooS* pp. 386-406). ' 134,000 B.t.u. latent heat and 1,000 X 905 = 905,000 grains or 129 lb. of water vapor will be added per hour to the air in the auditorium. These sensible and latent heat joss additions may also be found as follows: T(^, effective temperature of the condition 75 deg. dry-bulb and 63.5 deg. wet-bulb is 7oJ deg. effective temperature. From Fig. 6 find 403 B.t.u. as the total heat added to the air by a- person for 70.3 deg. effective temperature. From Fig. 9 find the percentage of sensible and latent heat at 75 deg. dry-bulb to be 66.5 per cent and 33.5 per cent. The sensible heat added to the air in the auditorium is 1,000 X 0.665 X 403 = 267 995 B.t.u. per hour. The latent heat added is 1,000 X 0.335 X 403 = 135,005 B.t.u. per hour. Solution--Problem 1-B: From Figs. 7 and 8, respectively, the sensible and latent heat losses per person for 85 deg. dry-bulb are found to be 164 and 225 B.t.u. per hour. The water vapor added to atmosphere is 1,520 grains per hour. The audience will then add 164,000 B.t.u. sensible heat, 225,000 B.t.u. latent heat and 1,520,000 grains or 217 lb. of water vapor to the air in the auditorium per hour. Problem S: Neglecting the gain or loss of heat to an auditorium by transmission or infiltration through the walls, windows and doors, how many cubic feet of outside air, with 65 deg. dry-bulb, 59 deg. wet-bulb and 63.1 deg. effective temperature must be added per hour to an auditorium containing 1,000 people in order that the inside shall not exceed 75 deg. dry and 65 deg. wet-bulb, respectively? Table 3. Condition of Sensible Perspiration for Persons Working at Hard Labor for Various Atmospheric Conditions Atmospheric Condition Degree or Perspiration* 95 Per Cent Relative Humidity 20 Per Cent Relative Humidity E.T. D.B. W.B. E. T. D.B. W.B. Forehead clammy ........:.-.______________ Body clammy.......... .. .......... ............................... Body damp _____ ________________________ Beads on forehead..................... ........................ Rnriy wpf ...... ............. .......... ..... . ... Perspiration on forehead runs and drips Perspiration runs down body.................................. 59.0 50.0 60.0 68.0 69.0 78.5 79.0 59.4 50.2 60.3 68.5 69.6 79.3 79.8 58.3 49.3 59.3 67.5 68.5 78.0 78.5 69.5 57.0 62.5 76.0 71.0 82.0 81.0 80.5 61.6 69.6 91.0 82.8 100.5 99.8 56.5 44.2 49.5 63.4 53.0 70.2 69.0 Forty per cent of subjects registered degree of perspiration equal to or greater than indicated. '' Chapter 26--Ventilation Standards Problem S: Figs. 7 and 8 give 265 B.t.u, sensible heat and 905 grains of _ as the additions per person with 75 deg. dry-bulb in the auditorium. ThereSSSTnOO B.t.u. of sensible heat and 905,000 grains of moisture will be added to the a'i'AaHthnega0u.2d4itoasriuthme pspeer chioficurh. eat of air, 2.4 B.t.u. per pound of air will be required to zthe dry-bulb temperature from 65 to 75 deg. and ^ = 110,400 lb. of air or $400 X 13.4 = 1,479,000 cu. ft. of air per hour will be required. This is equivalent ~~ -l.479.00Q_ _ 24.7 cu. ft. per person per minute. The moisture content of the inside air as taken from a psychrometric chart is 76 grains 06&,, noOunXd Wof dry air and that of the outside condition is 65 grains so the increase in # QQk fWJ ooisture content will be 11 grams per pound of dry air. ~j~ = 82,300 lb. of dry air r approximately 83,000 lb. of air at the specified condition will be required. This is ijuivalent to 83,000 X 13.4 = 1,112,000 cu. ft. of air per hour or = 18.5 a .,Tfth.eohf iagihreprevromluimnueteopf 2e4r .p7ecrsuo.nf.t. per person per minute will be required to keep the ty-bulb from rising above the 75 deg. specified. The wet-bulb will, therefore, not rise o tEhxeammapxilmesum1-oAf 6a5nddeg1. -B demonstrate that while the effective tempera ture, and, hence, the feeling of warmth arid rate of total heat loss, does not differ greatly in the two cases, the relative proportion of sensible and latent heat loss is reversed. In order to maintain the air conditions stipulated the air conditioning equipment must remove 61.6 per cent more sensible heat in (1-A) than in (1-B); and 67.8 per cent more latent heat or water vapor in (1-B) than in (1-A). In (1-A) 66.5 per cent of the total heat loss is sensible while in (1-B) only 42.5 per cent of the total loss is sensible. > SYNTHETIC AIR CHART The form of the Synthetic Air Chart has been slightly modified since it was originally adopted by Hie Society and the form here presented is the one in use at the present time. (See Synthetic Air Chart, by E. Vernon Hill, A.S.H.V.E., Transactions, Vol. 23, 1917). h ---------- ' DesTjorcchemerrsiippu.SlttytiisIoannonntshfteeooteatiffsdctttsAhoh*afe'eirrse^CCpC4pehhhlaoaaaktriitrrtnett;gidsodofensthaigecnhevdaernfto,tirlaanmtidoentahsoeufraianirgrcotohonemdaitaiiorsncgsoonoadsdi,taiobwnahsdomoleradiinnedttaeifirfnmeeridenneintd, iThpiesricsednotangeebbyapslios.ttin(Fgitge.s1t 0d)a.ta for all known factors that make up the air conditions, ese factors with their proper weights are arranged in vertical columns across the chart. The base of each column represents ideal conditions, or 100 per cent perfect. The umns are seven in number, and the first six are indicated by the capital letters, 111 kiw.v__, B, C, D,E,FA. = the Effective Temperature Diff~erence, o-r t-he,,ammoouunntt of variation from the ideal effective temperature. B -- Dust Particles per Cu. Ft. DC --= BPaecrcterniata.ge of freedom from objectionable odors. - . rorts oer 10,000.