Document VJ1oY55vv1ZeJ8Qpmo07Lr6LN

80 CHAPTER 5 1962 Guide And Data Boole Table 14.... Determination ofFree Area and Total Pressure Loss of Register for No Deflection of Air** Register Free Air m Sqwn indies (Upper vafae in eodi group) Pressure loss in Inches of Water Column (lower value h each group) Oisfance from Register fo Opposite WoO Ofcfaace from Register te Opposite WeO 17-21 22-24 25-27 26-30 3!-34|35-39 40-49 50-59 60-49 35-39 40-49 50-59 l*n-AO 7(1--70 190*-209 i t I1 62 47 37 30 24 18 0.02 0.03 6.04 0.06 0.09 0.15 660-699 i ' I 1' 210 143 95 69 49 0.02 0.03 0.07 0.12 0.22 210t-229 76 58 45 36 29 22 0.02 0.02 0.04 0.05 0.08 0.12 700-739 236 160 107 77 54 0.02 0.03 0.06 0.11 0.21 230-249 69 53 43 34 26 0.02 0.03 0.04 0.07 0.11 740-779 262 179 119 86 61 0.02 0.03 0.06 0.10 0.18 250L269 '81 63 50 40 31 21 0.02 0.03 0.04 0.06 0-09 0.18 780-819 291 198 132 95 67 0.02 0.03 0.05 0.09 0.17 270`-299 93 73 59 47 36 24 0.02 0.02 0.03 0.05 008 0.16 820-859 320 218 145 105 74 0.02 0.03 0.05 0.08 0.15 300<-339 95 77 61 46 32 0.02 0.03 0.04 0 06 0.12 860-899 352 0.02 240 0.02 160 0.04 115 0.08 81 * 0.14 340`-379 120 97 77 59 40 0.02 0.02 0.03 0.05 0.10 900-939 385 262 175 128 89 0.01 0.02 0.04 0.07 0.13 380M19 119 ' 95 .73 50 0.02 0.03 0.04 0.08 940-979 419 285 190 137 97 0.01 0.02 0.04 0.07 0.12 420*-459 149 114 88 60 0.02 0.03 0.04 0.07 980-1019 455 309 206 148 105 0.01 0.02 0.04 0.06 0.11 460M99 171 136 105 71 0.02 0.02 0.03 0.06 1020-1059 493 335 223 161 113 0.01 0.02 0.03 0.06 0.11 500`-539 160 123 84 0.02 003 0.05 1060-1099 530 361 241 173 123 0.01 0.02 003 0.06 0.10 540*-579 186 143 97 65 47 1100-1139 571 388 258 186 132 93 0.02 0.02 0.05 0.09 0.17 0.01 0.02 0.03 0.05 0.09. 0.17 580M519 620`-659 213 164 111 74 64 0.02 0.02 0.04 0.08 0.15 180 127 85 61 0.02 0.04 0.07 0.14 1140-1179 1180-1219 416 277 199 141 100 0.02 0.03 0.05 0.08 0.16 446 297 214 151 ior 0.02 0.03 004 0.08 0.15 AB Footnotes for Table 14 * If reebte'selected based on distance from register to opposite wail is unsatisfactory on aeooont cl m or pressure loss, it is permissible to shift one or more spaces left or right in the tables to obtain a more suitable register. If requirements tell in blank space, select two register* b, place of one and divide CFH capacity between the two registoa. b Total Wesson (static pins velocity) loss b based on FLAT FACE ADJUSTABLE BAB TYPE ana does NOT include stnrlrhrerf ' Values on the right of line A and A' should not be used in applications suob a* eburcbea, eaditartnm*, and concert' halls. 4 Values on tight of line B and B' should not be osed in applications such a* residential work, motion picture theaters, court rooms, end schools. * For floor and baseboard. registers where a velocity of approximately 100 FPM b used, the free area -- --or approximately,--j-- . Assume a pressure loss of &0L f For any volume under 290 CPU use Table 13. 1220-1259 1260-1299 1300-1339 1340-1379 1380-1419 1420-1459 1460-1500 476 317 228 161 116 0.02 0.03 0 04 0.07 0.14 507 338 243 172 122 0.01 0.02 0.04 0.07 0.13 539 359 258 183 130 0.01 0.02 0.04 0.07 0.12 382 274 195 138 0.02 0.04 0.07 0-12 403 290 206 146 0.02 0.03 0.06 0.12 308 218 155 0.03 0.06 0.10 324 230 163 0.03 0.06 OHO Warm Air Heating Systems 81 Table 15.... Suggested Bonnet Pressure Inches of Water Intel CFM Through -Aaf One Pod Suggested flannel Pressor* la. Water Tohd CFM Through Any One Duel Suggested flannel Pressure la. Water 800-1000 1000-1200 1200-1800 1800-2400 2400 to 3500 0.10 0.10 0.10 0.13 0.14 3500 to 5000 5000 to 7500 7500 to 10,000 10,000 to 12,000 12,000 to 14,000 0.15 025 0.375 0.500 0.750 the ducts. Hence, ducts need not be insulated except as fol lows: 1. Supply ducts: A. Located in enclosed, unhealed spaces--1 in. of insula tion. B. Located in spaces exposed to outdoor temperature-- 2 in. of insulation. 2. Return ducts--1 in. of insulation when not located in heated space. The procedure for larger systems may also be used to design perimeter systems in which the trunk duct is em bedded in the concrete slab floor, usually just inside the foundation wall.19 In such systems the branch ducts are usually very short and consist only of the take-off fitting, the diffuser boot or stackhead, and a short length of riser. The trunk is installed in the same manner as the loop duct in a smaller installation, and is often insulated to reduce heat loss and prevent overheated floors above the duct. Perimeter in sulation must be used between the foundation wall and duct. automatic controls Air stratification, high bonnet temperatures, excessive flue gas temperatures, and heat ovemm-or lag in a properly de signed system, can be largely eliminated through' proper care in.the planning and installation'of the control system Best results are obtained when the fan is operated as con tinuously as possible, coupled with frequent; short cycles of burner operation. Controls usually employed are: 1. A room thermostat located in the occupied space at a point where there is good air circulation and where the tempera ture is representative of the area being controlled. It is the operating control which initiates the starting and stopping of toe burner. It is frequently of the timed, two-position type. Refer to Chapter 13 of the 1961 Guide And Data Boos for more information on types of room thermostats. 2. A fan thermostat located in the bonnet of the furnace to start the fan at a bonnet temperature 10 to 15 deg above room temperature and stop the fan at about 15 deg below the cut-in point. The lower settings are used for high side-wall register in stallations and the higher settings for baseboard register install*bons. For most satisfactory performance these settings should be as low as is feasible without resulting in drafts. 3. A high Hmit control, also in the bonnet of the furnace, to top- the burner independently of the room thermostat if the temperature exceeds 200 F. The fan.thermostat and high hmit control are sometimes combined into a single unit. 4. A humidistat to regulate the moisture supplied to the ^oonis on systems which are equipped with humidifying means. Awa may be of the room type, usually located adjacent to the room thermostat, or it may be of the insertion type located in the main return air duct. 5. Primary and limit controls for the various types of gas burners, oil burners and coal burners (stokers) should be pro vided as required, and are discussed in Chapter 42 of the 1961 Guide And Data Book. adjustment of system More even room temperatures will result if the controls are adjusted to produce long period fan operation. This is accomplished in automatically-fired forced warm air heat ing systems when the control arrangement is of the type where the room thermostat controls the fire, and the blower control (fan switch) controls the blower operation. This procedure as outlined in detail in Manual 6 of the National Warm Air Heating and Air Conditioning Association, is as follows:* 1. Adjust the fuel input in proper relation to the heat loss of the structure. 2. Determine the temperature rise through the furnace. 3. Adjust the air volume to produce a temperature rise through the furnace of about 99 deg. 4. If adjustable, set the fan switch differential to a minimum of about 15 deg. 6. Adjust the fan switch cut-out point as low as practicable. 6. Balance the system by adjusting dampers to produce even temperature distribution between rooms. 7. Set the room thermostat at the desired room temperature. Close control of room temperature is facilitated by the use of a room thermostat having a narrow operating differential. The heat anticipating thermostat is such a device. WARM AIR CHUNG PANEL SYSTEMS Warm air ceiling panel heating systems utilise a false ceil ing suspended 314 in. from the ceiling joists which have previ ously. been covered oh the bottom with sheets of plaster board. Special hangers are used to suspend the false ceiling or heating panel from the joists. Steel supporting'rods are installed through these hangers and metal Lath is attached to the rods. The lath is then plastered to a thickness of Y* in., making a completely sealed air space above the ceiling. Warm air is delivered to this sealed space through a stand ard warm air duct, installed in the usual manner. The air is then circulated over the entire ceiling being guided by sheet-met&l baffles. After the air has pased over the ceiling, it is returned to the furnace through a return air duci for reheating. The system is closed, and no air is introduced into tiie heated space from the panel. (See also Chapter 10, Panel Heating.) Because a warm air ceiling panel system involves a differ ent type of ceiling construction, its installation is practically limited to new construction. Only automatically-fired and thermostatically-controlled furnace-blower units may-be used with this system. The standard automatic heating con trols consisting of a room thermostat, temperature limit con trol, blower control (fan switch), and primary control are all that are required. While warm air filing panel heating has particular advantages in one-story utility room houses, it can be just as effectively installed in one- and two-story houses with basements. Complete design and installation procedure is given in Manual 7-A of the National Warm Air Heating and Air Conditioning Association.1* SUMMER OPERATION During hot summer periods a slight cooling effect may sometimes be obtained by the circulation of basement air through the system. This beneficial effect is due to both the increased air movement in the occupied spaces and the small reduction in dry-bulb temperature brought about by