Document wKK7px4YLNQ6ja86Xedz6K4d4

68 CHAPTER 5 1962 Guide And Data Book Table 5.... Bfuh Capacities and Cftn of Individual Duds in Perimeter Systems _____________ Used in Crawl-Space or Basement Construction (Concluded)______________________________ Section C For 6'htdi individual Round Pipe and for Baseboard Diffoen Only Bonnet Pressure 0.15 tn. Static Bonnet Temperature 170 P No. of Sbon Actual length el Pipe From Sonnet fo Oifhrter--feet 5 to 13 20 25 30 35 40 45 50 55 60 65 70 75 80 0 Btuh Cfm 8570 8000 7450 6910 6420 5960 5560 5150 4800 4450 4160 109.0 107.2 105.5 103.7 102.0 100.4 98.8 97.5 96.1 94.8 93.5 1 Btuh Cfm 2 Btuh Cfm 3 Btuh Cfm 4 Btuh am 5 Btuh am 6 Btuh Cfm 8700 8100 7550 7000 6520 6060 5630 5250 4860 .4630 4220 3930 105.5 104.0 102.3 100-7 99.2 97.6 96.2 95.0 93.6 92.3 91.1 90.0 8890 8270 7700 7160 6660 6200 5750 5350 4980 4620 4300 4000 3700 102.8 101.3 99.8 98.2 96.7 95.3 94.0 92.7 91.5 90.2 89.0 87.8 86.5 8440 7870 7320 6820 6350 5880 5460 6070 4700 4350 4020 3710 3440 98.4 96.8 95.3 93.9 92.5 91.3 90.0 89.0 88.0 86.9 85.8 84.7 83.5 8690 8080 7500 6980 6500 6030 5580 5180 4800 4450 4120 3820 3520 3250 95.8 94.4 93.0 91.6 90.3 89.0 87.8 86.7 85.7 84.6 83.7 82.6 81.6 80.5 8940 8320 7740 7200 6680 6190 5720 5320 4920 4550 4220 3890 3600 3350 3100 93.4 92.2 91.0 89.8 88.5 87.3 86.2 84.8 83.8 82.8 81.7 80.8 79.9 79.0 78.0 8580 7960 7380 6850 6350 5880 5440 5040 4660 4320 4000 3670 3400 3150 2930 90.0 89.8 87.6 86.5 85.5 64.2 83.1 82.0 80.9 80.0 79.0 78.0 77.3 76.5 76.0 Tb Equivalent Leaxtb Value* (Bed *ad Included in cwlcuUtiag thb table ore: Difluaer end Boot 100 ft; Plenum Take-off -- 20 ft; Each Elbow " 14 ft. For each II ft nf KiW All elm valaee ere based on etaadard air. This is a preliminary estimate of tbe number of diffusers needed. 4. Measure the length and count the number of elbows in each feeder duet. Determine Btuh capacity of each feeder duct from Table 4. Use Table 4 (Section A) for side-wall and floor diffusers and Table 4 (Section B) for baseboard diffusers. 5. If the total Btuh capacity of all feeders to each room or area equals or exceeds the heat loss of that room or area, the number of feeders initially chosen is satisfactory. If the heat loss exceeds the Btuh capacity of the feeders, use and locate additional diffusers and feeder-ducts. 6. Tbe cfm values in Table 4 are used for designing the return-duct system. Perimeter-Radial System m Crawl Space or Base ment Construction The perimeter concept of warm air heating has been ap plied to crawl-space and basement homes by locating the diffusers in the perimeter location and by warming the area underneath the floor of such structures. Although the con struction of the crawl space and the foundation wall is the responsibility of the architect and the general contractor, it is important that the engineer check the construction to make certain that it will not adversely affect the perform ance of the heating system. Details on crawl-epace con struction are shown in Manual 4 of the National Warm Air Heating and Air Conditioning Association* Tbe crawl space or basement should be heated to provide warm floors. A simplified design procedure* for an individual duct sys tem is summarized as follows: 1. Calculate the heat loss of each room or area using the explained in Chapter 25 of the 1961 Guide And Data Boos. Consider tbe basement or crawl space as a part of the structure and calculate its beat loss. Information in Manual Jl# supplements th-t contained in Chapter 25, particularly with respect to crawl-space heat losses. 2. Determine the required furnace-bonnet capacity from the heat loss of the building. 3. Locate the diffusers on the plan. Allow at least one dif fuser for each exposed wall in each room or area of building, and locate them preferably beneath window areas. For resi dential installations limit each diffuser to a maximum of 7/300 Btuh. 4. Determine the required Btuh delivery of each diffuser. Where more than one diffuser is used per room, proportion the heat lorn equally among all diffusers. 5. Measure length and count number of elbowa in each dud. From Table 5, determine the duct size (5 or 6-in. diameter) needed. Section A is for 5-in. duct. Section B is for 6-in. dud using side-wall or floor diffusers, and Section C is for 6-in. dud using baseboard diffusers. Perimeter Extended-Plenum Systems in Crawl- Space or Basement Construction The considerations involved in the design of extendedplenum systems are esentially the same as those of the in dividual pipe system. A amplified design procedure is sum marized as follows: 1. Calculate the heat loss of each room or area using the method explained in Chapter 25 of the 1961 Guide And Data Book. Consider the basement or crawl space as a part of tbe structure and calculate its heat loss. Information in Manual Jta supplements that contained in Chapter 25, particularly with respect to crawl-space heat losses. 2. Determine the required furnace-bonnet capacity from the heat loss of the building. 3. Locate the diffusers on the plan. Allow at least one dif fuser for each exposed wall in each room or area of building, and preferably beneath window areas. For residential installa tions limit each'diffuser to a maximum of 7,000 Btuh. 4. Determine the required. Btuh delivery of each diffuser. Where more than one diffuser ta used per room, proportion the heat loss equally among all diffusers. 5. Measure the length of each duct and count number of elbows from the extended plenum to the diffuser. Note whether top or side plenum take-offs are to be used. From Table 6. determine the duct size needed. (Note: Use that section of Table 6, Sections A to F, which applies both to the type of plenum take-off and diffuser to be used.) 6. The cfm values in Table 6 are used with Table 7 for y^arm 'Air Heating Systems 69 Table 6.... Healing Capacities and Cfm of Brandi Ducts in Extended Plenum Perimeter Systems Sedtoft K Sid* Taka-off to 5-bx* Round PIpa forSida-waO, Floor, ond Bareboard Dttfwoo Extended-Plenum Pressure 0.11 in. Static at ISO F_________ Furnace-Plenum Pressure 0.15 in. Static at 170 P Actoaf Uftgfb hen tslended-ffeima to Dffuret--feel 0 2'. 3 4 5* 6 5 10 15 20 Btuh . am Btuh ~ am Btuh am ' Btuh am Btuh Cfm Btuh ` am Btuh . Cfm 8960 97.2 8100 93.1 8070 7290 88.4 ' 65.2 7340 6650 81.1 .78.6 6810 75.0 6180 73.0 6350 70.4 5750 68.8 5970 65.2 5400 64.8 5660 . 5120 63.0 61.5 7310 89.4 ` 6580 82.2 6020 76.0 5600 , 71.0 5210 67.0 4900 63.2 4630 60.2 6550 86.0 5950 79.3 5460 73.9 5070 69.2 4740 65.4 4440 62.0 4190 59.1 25 30 5900 83.0 5400 76.9 4950 71.9 4610 67.3 4300 64.0 4040 60.7 3800 58.0 5310 81.2 4880 74.6 4600 70.0 4200 65.8 3900 62.5 3670 59.4 3430 56.9 35 4800 77.7 4400 72.5 4070 68.2 3800 64.4 3530 62.1 3330 58.3 3100 55.9 40 4330 75.5 3980 70.7 3680 66.6 3420 63.1 3180 60.0 2990 57.4 2800 55.1 45 50 3900 73.1 3510 71.1 3550 3200 68.9 67.1 3300 64.1 2980 63.7 3080 ; 61.7 2870 58.8 2770 60.2 2570 57.7 2770 56.2 2410 65.3 2520 54.0 2270 53.0 55 60 3170 69.3 2850 67.8 2900 65.7 2620 64.2 2680 62.3 2410 61.0 2480 59.0 2230 58.2 2300 . 2070 56.7 55.9 2160 54.4 1930 53.7 2040 52.2 1800 51.8 Note: Where toy of the fint three run from the extended-plenum exceed! 10 ft and 3 elbowa, count 3 extra elbowa for that run. Tbe Equivalent length Values used and included in cslcuUtin* this table ere: DiSuaer and Boot * 35 ft; Tapered Extended-Plenum Starting Collar. Elbow - 12 ft; aia. Tako-off . ft. * Section B. Top Take-off to 5-lndi Roond Pipe for Side-wad, Floor, and Baseboard DJffwer* Extended-Plenum Pressure 0.1S in. Static at 160 F Furnace-Plenum Pressure 0.16 in. Static at 170? No. of Show* 5 0 Btuh 7070 am 77.8 1 Btuh 6570. Cfm 72:6' 2 Btuh 6180 Cfm 68.4 3 . Btub 5800 am 64.4 4 : Btuh 5490 Cfm 61.2 5 . Btub - . 5200 Cfm 58.5 6 Btuh 5000 am 56.0 Aefvol length front xteeded-fteatm to Piffvrer Feet 10 15 20 6400 75.6 5800 73.4 5260 71.4 5970 70.8 5400 68.9 4890 67.2 5610 66.8 5080 65.2 4590 63.7 5250 . 4750 . 4310 63.1 61.8 60.5 4960 . 4500 60.0 58.8 4080 57.8 4710 57.5 4280. 3870. 56.5 55.5 4520 . 5100 55.0 54.0 3700 53.4 25 4800 69.5 4430 65.6 4160 62.3 3900 59.3 3700 56.7 3510 54.5 3350 52.4 30 35 40 45 50 4350 68.0 3940 66.4 4010 64.2 3640 62.8 3770 61.1 3410 60.0 3540-' 3200 58.3 57.1 3340 55.8 3020 54.9 3180 S3.7 2880 52.9 3010 2700 51.7 51.0 3550 64.8 3290 61.5 3080 58.7 2890 56.3 2720 54.1 2580 52.1 2440 50.5 3190 63.4 . 2950 60.3 2770 57.6 2600 55.5 2440 53.3 2310 51.4 2160 59.7 2870 62.0 2650 59.0 2480 56.4 2340 54.7 2200 -52.6 2060 50.7 1910 49.1 55 2580 60.6 2380 58.0 2210 55.3 2100 53.9 1970 51.9 1830 50.0 1700 48.6 Note: Where any of the first three runa from the extended-plenum caxceda 20 ft and 3 elbowa, count t extra elbowa for that nut. Tbe Equivalent Length Valoea need and included in ralrniating this table are: Diffuasr and Boot 83 ft; Each Elbow - 13 ft- Too Takeoff - SO ft TaDered Extended-Plenum Startin* Collar. '^ 60 2310 59.5 2140 57.0 2000 54.4 1870 53.2 ' 1750 51.1 1640 49.5 1551 48.1 the extended-plenum system. No one extended plenum a exceed 35 ft in length. design of Return Duct System for Perimeter In stallations With perimeter systems designed in accordance with the foregoing simplified procedures, there is a circulating head of only 0.05 in. water available on the return ride C^the system. It is therefore necessary that the return ducts be adequately sized and be as short and straight as practicable. The return grilles may be centrally located, and the ducts may be located in the attic or other unheated spaces pro vided they are adequately insulated. Return air may be