Document o9Z6zpXQJJqokNe85GmMXzMBg

488 CHAPTER 19 1958'Guide mum perimeter 210 ft, and maximum length of uninsulated, feeder duct 30 ft for area served by one furnace; is the following: ' 1. Calculate the heat loss for each room using the methods explained in Ghapter 12. For subfloor and edge losses,* see Manual 3 of the National Warm Air Heating and Air Conditioning Association. .2. Determine the required furnace-bonnet capacity from the heat loss of the building. Fig. 5. Cboss-Section of Slab Construction Containing Perimeter Duct* The minimum thickness of concrete over the loop duct should be 2V6 in., and continuous mesh reinforcing not less than 6 z 6-10 gage and 18 in. wide should be placed in the concrete and centered over the duct. 3. Locate the diffusers on the plan. For best heating results, if a room has a heat loss of more than 8,000 Btuh or if it has-two or more exposed walls, use two or more diffusers. Proportion the Btuh.heat loss of,each room among all diffusers in that room. * .. 4. Locate the feeder ducts. * First, divide the heat loss of the structure by 15,000 to determine the probable number of feeders. Second, locate the ducts so that they connect with the perimeter-loop at areas of greatest heat loss or in rooms where warm floors are particularly desirable. Third, locate the feeder dilcts so that no more than 3 diffusers are in the section of loop duct between any two feeders. (The final number of feeder ducts may be larger than that originally estimated.) 5. Determine the size of feeder ducts using Table 1. Assume that the Btuh re quired by each diffuser will.be supplied by the feeder nearest it. Determine the feeder duct diameter from its length and the total diffuser Btuh delivery carried by it. 6. Determine the total diffuser free area required in each room using Table 2. Measure the length of feeder duct under each room. Add to this one-half of the length of the loop duct, and determine the total diffuser free area required. Appor tion this among all diffusers.in the room. 7. The diameter of the loop duct should be uniform and.equal to the diameter of the largest feeder duct. Perimeter-Radial Systems in Concrete Slab Construction The perimeter-radial system, Fig.! 6, is similar to the perimeter-loop system in that the supply ducts are embedded in the concrete slab. The Table 1. Diameter of Feeders in Perimeter-Loop System Length or Feeder in Feet up to 7,999 8,000 to 8,999 9,000 to.10,999 11,000 to 11,999 12,000 to 12,999 13,000 to 17,000 0-15 Feet Inches 6 6 7 7 7. 8. 16-30 Feet Inches 6 7 7 8 8 8 \ \ . .\ \ .. \ Warm Air Heating Systems `489 Table 2. Minimum Diffuser Free Area Required for PerimetertLoop^Systems SECTION A. USE THIS TABLE IF LENGTH OF FEEDER WHICH DELIVERS MAJORTORTIOIC >; OF'WARM AIR TO'ROOM IS FROM 2 TO 10 FT. . , i ; :l| ' - Heat Loss or Room - Btuh per Hr. < Length or Feeder Duct under Room Plus Vi Length or Perimeter Duct Under Room, Ft. 0-9 Ft: ' 110--19 Ft. . 20-29 Ft. 30-39 Ft. 40-49'Ft! 50-^59 Etj - 60-69 Ft: 0 to 3,999 4,000 to 5,999 6,000 to 7,999 8,000 to 9,999 10,000 to 11,999 12,000 to 13,999 14,000 to 15,999 16,000 to 17,99918,000 to 19,999 20,000 to 21,999 22,000 to 23,999 ' 24,000 to 25,999 26,000 to 27,999 28,000 to 29,999 30,000 to 31,999 32,000 to 34,000 Total Diffuser Free Area Required for Room , Square Jnches 20 32 ' 27 43 1 - 39 23 34 55 66 . 77 50 72i 45 57 68 ; 88 100 m 84 95 106 79 . 91. 102 122 118 134 "129 145 140 113 125 136 156 M51 * .147 168 163 -159 179 174 - 170 190 185 182 18 29. - 41 62 63 75 86 97 109 120 131 . 142 ; 154 165 176 25 : 20 - = 36 32 27' 48 43. * ` 38 59 54 50 . 70* ' 66 - - . .82 . . - 77 93 88 61 .'72;v 84 104 100 118 ' 111 127 122 95 108 118 138 i33 129 150 145 141 161 156 152 173 167 164 SECTION B. USE THIS TABLE IF LENGTH ; OF FEEDER WHICH DELIVERS MAJOR PORTION OF WARM AIR TO ROOM IS FROM 10 TO 20 FT. . 0 to 3,999 4.000 to 5,999 6.000 to 7,999 8,000 to 9,999 10,000 to 11.999 12,000 to 13,999 14,000 to 15.999 16,000 to 17,999 18,000 to 19,999 20,000 to 21,999 22,000 to 23.999 24,000 to 25,999 26,000 to 27.999 26,000 to 29.999 30,000 to 31.999 32,000 to 34,000 23 1836 -31 49 - ' 44 61 . 73 . 86 ' ' 56 68 81 99 94 111 106 123 118 135 i3d 148 .143 161 156 174 168 186 181 198 194 211 206 18 26 21 39 '* 34 ' 16 : 29- 51 46 ' 41 63 58 ' 53 76 71 66 89 84 79 .101 96." 91 113 108 , . 103 125 120 115 138 133 128 151 146 141 164 ` 176 188 201 . 158 171 184 - 196 154 166 178 191. 16 .24 19 36 31 .48 43 61 56 74 86 98 no . y1m23' ` 69 81 93 105 118 131 ` i48 161 -174 r 186 /144 156 168- ; 181.. SECTION C. USE THIS TABLE IF LENGTH OF FEEDER WHICH DELIVERS MAJOR PORTION OF WARM AIR TO ROOM IS FROM 20 TO 30 FT. . > 1 3,999 4,000 to 5,999 ____ 6,000 to 7,999 ,*!> to 8,999 10,000 to 11.999 12,000 to 13,999 14,000 to 151999 16,000 to 17.999 18,000 to 19,999 , 20,000 to 21.999 ^ 23,999 *4,000 to 25,999 28`SSS to 27,999 loam ^ 29,999 .899 M.000 to 34,000 27 42 57 72' 86 101 : - 116 131 145 160 175 190 205 220 234 249 21 21 36 30 51 45 66 ' ; 60` ' ; 80 74 `95 89 . 110 . 125 139 104 119 133 154 169 184 ... 148 163 178. . 199 214 228 243 193 208 222 237 24 39 54 68 83 98 113 127 142 157 172 187 202 216 231 18 33 27 21 48 62 - 77 . 42 56 71 . . 36' 50 65 92 86 *;80m-" 107 101 . 95 121 115 136 ' . 130' ^ 124 151 - : 145i';<" >139- : 166 .. .... J60. , 154 . . 181 196 210 225 175 169, . 190 184 204 ' -108 . 219 213