Document 93k1vwQ16JJov6exnkgwMjBGq

264 CHAPTER 18 1960 Guide Table 12 .... Selection of Bonnet Temperature/ Register Temperature and Register Delivery (CFM)*'b (For BuHdingt Honing a Hoot Lots Greeter than 350,000 8TC//HrJ Bogidor OeRvery Votes* in CfM pot 1000 BTU por Hr. Sennet Temp. *F *tear 2 isisaei from Sooner io Register, h Foot 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 140 170 180 190 200 210 220 230 240 140 138* 136 134 132 130 128 127 126 125 124 123 121 120 119 118 117 116 115 114 113 112 111 110 109 14.0* 14.4b 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 17.6 18.1 18.4 18.7 19.0 19.3 19.6 20.0 20.3 20.7 21.1 21.6 22.1 22.5 150 148 146 143 141 139 137 135 133 131 129 128 127 126 124 123 122 120 119 118 117 116 115 114 113 12.6 12.8 13.1 13.5 13.9 14.2 14.6 14.9 15.3 15.7 16.2 16.4 16.6 16.9 17.3 17.6 17.9 18.4 18.7 19.0 19.3 19.6 20.0 20.3 20.7 160 158 165 152 150 147 145 143 140 138 136 134 132 130 128 127 126 125 124 123 121 120 119 118 117 11.4 11.6 12.0 12.3 12.6 12.9 13.2 13.5 14.0 14.4 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 17.6 18.1 18.4 18.7 19.0 19.3 170 167 164 161 158 155 152 150 147 145 143 140 138 136 134 132 130 128 127 126 125 124 123 121 120 10.5 10.7 11.0 11.3 11.6 12.0 12.3 12.6 12.9 13.2 13.5 14.0 14.4 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 17.6 18.1 18.4 180 177 173 170 167 164 161 158 155 152 150 147 145 143 140 138 136 134 132 130 128 127 126 125 124 9.7 9.9 10.2 10.5 10.7 11.0 11.3 11.6 12.0 12.3 12.6 12.9 13.2 13.5 14.0 14:4 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 190 186' 182 178 175 172 168 165 162 159 156 153 151 148 146 143 141 139 137 135 133 131 129 128 127 9.1 9.3 9.6 9.8 10.0 10.3 10.7 10.9 11.2 11.5 11.8 12.2 12.4 12.8 13.1 13.5 13.9 14.2 14.6 14.9 15.3 15.7 16.2 16.4 16.6 200 196 191 187 183 179 176 172 169 166 163 160 157 154 151 149 147 144 142 140 138 135 133 131 130 8.6 8.8 9.0 9.2 9.5 9.8 9.9 10.3 10.6 10.8 11.1 11.4 11.7 12.1 12.4 12.7 12.9 13.4 13.7 14.0 14.4 14.9 15.3 15.7 15.9 * Rccictex temperature, Fahrenheit. <Un upper value in each group.) b Recbto- delivery volume tn cubic feet per minute per 1000 Btu. (Use lover value in each group.) ' Register delivery volume* in mImbb I ub far sero length of dock (such as Fig. 2, or Fig. 3, Chapter 21), volume (cfm), and pressure drop per 100 ft of duet. B. Return air branches. a. Select a low value of actual duct loss obtained from step b under item A for the suction loss of return duct system. b. Proceed in sizing return air branches by the same' method described for the warm air branches. C. Trunk ducts for worm air and return air tides of system. a. Add air volumes of branches to be handled by each trunk duct. b. The friction loss per 100 ft of trunk duct is deter mined by taking the smaller of the two values for friction loss for the two ducts meeting at the junc tion. - e. Determine trunk duct size by using an air friction chart, volume, (cfm), and pressure drop per 100 ft of trunk duct. . Selection of Blower. . A. Determine total cfm air delivery (the sum of all branch cfm values). B. Determine static pressure requirement. a. For furnace-blower combination units it is tbe sum of bonnet pressure and suction pressure, b; For blowers separately selected from the furnace it is the sum of bonnet pressure, suction pressure, filter loss, casing loss, losses through air washers, coils, and other devices.' . Selection of Furnace. A.' Determine register delivery (the sum of room Btu losses). B. Determine bonnet capacity. If the ductwork is all lo cated in spaces that nave oeeu included in the calcu lated heat loss, the required bonnet capacity can be .considered equal to the required Btuh register deliv ery. If the furnace and ductwork are located in spaces not included in the heat loss, tbe required bonnet capacity of the furnace can be determined from: Btuh -- (cfm) X (temperature rise) X (1.08) C. Determine allowance for pick-up load. For buildings which are heated intermittently, such as churches and auditoriums, it is customary to add from 10 to 25 per cent extra furnace capacity for wanning of the struc ture. The design procedure outlined above results in a duct system which has been described as a trunk-and-branch system. A trunk duct may or may not be reduced in size as each branch duct leaves the trunk. If tbe trunk duct is not reduced as each branch duct leaves the trunk duct, the trunk duct take-off fittings designated as EP1 to EP4 in Fig. 7 are used. The air velocity within a uniformly sized trunk duct decreases as air leaves it through the branch ducts. It is therefore desirable to reduce the trunk duct size frequently enough that the air velocity within it does not drop below about 350 fpin. The simplified procedures which have been outlined are based upon an assumed air temperature of 70 F surrounding Warm Air Heating Systems 265 Table 13___ Determination of Free Area and Total Pressure Loss of Register for 22 Deg Oeflection of Air*- Bogistor Free Atoo tn Squore Inches (Upper vote# in oodt groap) Frotpjro loss in Indtot of Wafer (tower value ht each group) Reodential Un Cto Reg. Size or F"Z"' Eqvitaioaf Up to 59 10x4 10 x 6 .01 .01 Cfm Readeofnri Uto Reg. Size or Equivalent Pressure loss 100-119 12x6 14 x 4 .02 .02 Distance -from Register to Opposite Wail Cfm 31-34 35-39 ldO-49 50-59 60-49 70-79 60-69 700-739 243 0.02 A' 1 186 127 85 0.03 006 0.11 60-69 10 x 6 .01 12 x 4 . . .02 120-129 12 x 6 14 x 6 .02 .02 740-779 271 208 141 94 0.02 0.03 0.05 0.10 70-99 10 x 6 12 x 6 .02 .02 130-169 14 x 6 .02 780-819 230 157 105 0.02 0.05 0.09 . 170-189 14 x'8 ' Distance From Register fo Opposite Wofi .02 820-859 254 173 115 0.02 0.04 0.08 Cfm 190-209 Up to 18 19-21 2224 2527 28-30j 31-34 i 35-39 *40-49 50-59 860-899 A ! 68 49 38 29 24 19 0-02 0.03 0.05 0.08 0.11 0.16 900-930 278 190 126 0.02 0.04 0.08 304 207 138 0.02 0.04 0.07 210-229 : 82 60 45 35 28 23 0.02 0.03 0.04 0.06 0.10 0.13 946-979 332 228 151 108 0.02 0-03 0.07 0.12 230-249 71 54 42 34 28 22 0.02 0.04 0.06 0.08 0.11 0-17 980-1019 360 245 163 118 0.02 0-03 0.06 0.11 250-269 84. 63 49 40- ...32 25 0.02 0.03 0.05 0.07 0.10 0-16 1020-1059 390 265 177 127 0.02 0.03 0.06 0.11 270-299 100 76 60 48 . 38' 30 0.02 0.03 D.04 0.06 0.09 0-13 1060-1099 285 190 137 0.03 0.06 0.10 300-339 96 73 60 48 370.02 0.04 0.05 0.07 0.11 1100-1139 307 204 147 0.03 0.05 0.09 , 340-379 122 95 78 61 47 33 0.02 0.03 .0.04 0.06 0.09 0.18 1140-1179 330 220 158 0.02 0.05 0.09 380-419 117 94 75 58 39 0.02 0.03 0.05 0.08 0.15 1186-1219 353 235 169 0.02 0.04 0.08 420-459 142 113 91 70 47 0.02 0.03 0.04 0.06 0.13 1226-1259 376 251 180 0.02 0.04 0.08 460-499 168 - 135 108 83 56 0.02 0.03 0.04 0.06 0.11 1266-1299 401 267 192 136 0-02 0.04 0.07 0.13 500-539 159 126 97 66 0.02 .0.03 O.Of 0.10 1306-1339 4% 284 204 144 0-02 0.04 3.07 0.13 540-579 .580-619 185 147 113 77 0.02 0.03 0.04 0.08 1340-1379 212*' 169 0.02 0.03 130 0.04 88 0.08 51 0.18 1386-1419 452 301. 217 154 109 0.02 0.04 0.06 0:12 0.22 479 319 230 163 116 0.02 0.04 0.06 0.12 0.21 620-659 ' 192 0.02 147 0.03 100 0.07 59 0.15 1420-1459 508 338 244 i72 122 0.02 0.03 0.06 0.11 0.20 666-699 . - -- 217 . 0.02 166 0.03 113 0.06 75 0.13 1466-1500 536 356 256 ' 182 129 0.02 0.03 0.06 0.10 0.19 * II register selected baaed as distance tram register to opposite wall i* onsatisfectory an account of aise or pleasure leas, it ia permissible to shift one or more eft or right In tbe tables to obtain a more suitable register. If requirement* fell ia blank apace, select two registers in place of one and divide CPU mpacity b tbe two register*.; _, .. . . b Total pressure (static plus velocity) toss is based on FLAT FACE ADJUSTABLE BAR TYPE end does NOT include atackbead. * Values on the right of line A and A' should not be used in implications such as churches, auditoriums, and concert halls. d Values on right of line B and B' should not be used in applications such aa residential work, motion mature theaters, court rooms, and schools-' * Por floor and baseboard register* where a velocity of approximately S00 PPM bused, the free ar--------------* W ~------------:-- of 0431. --. Assume a pitenure loss