Document LpMYrBxnyBNg2arV5Ey2meBDw
246
CHAPTER 18
1959 Guide
Table 6.. .. Heating Capacities and Cfm of Branch Duds in Extended-Plenum Perimeter Systems (Continued)
Section C Side Take-Off to 6-Inch Sound Pipe for Baseboerd Diffuser* Only
Extended-Plenum Pressure 0.16 in. Static at 160 F
Furnace-Plenum Pressure 0.16 i . Static at 170 F
Actual length from Extended-Plenum to Diffuier Feel
5 10 15 20 25 30 35 40 45 50 55 60
0
Btuh
9800
9100
8430
7820
7230
6700
6200
5730
5320
4920
4550
4210
Cfm
106.6 104.4 102.3 100.3 98.5 96.8. 95.0 93.1
91.7 90.0 88.5 87.2
1
Btuh
9230
8550
7930
7360
6800
6300
5830
5400
5000
4620
4280
3960
Cfm
100.4
98.7
97.0
95.3
93.7.
92.0
90.4
88.9
87.6
86.2
84.9
83.8
2
Btuh
8740
8100
7500
6960
6420
5960
5510
5110
4730
4390
4050
3750
Cfm
96.5
93.8
92.2
90.6
89.4
88.0
86.5
85.2
84.0
82.8
81.6
80.6
3
Btuh
8300
7690
7130
6600
6110
5680
5240
4850
4500
4170
3840
3560
Cfm
91.0
89.5
88.0
86.7
85.5
84.2
83.0
82.0
80.9
79.8
78.8
77.9
4
Btuh
7930
7350
6800
6290
5830
5400
5000
4620
4270
3940
3630
3370
Cfm . 86.8
85.5
84.2
83.3
82.0
81.0
80.0
79.1
78.0
77.0
76.1` 75.3
5
Btuh
7600
7020
6500
6020
5580
5160
4770
4410
4080
3770
3470
3190
Cfm
83.6
82.5 81.3
80.2
79.1
78.1
77.1
76.4
75.3
74.4
73.5
72.8
6
Btuh
7300
6760
6260
5780
5350
4950
4560
4200
3900
3580
3300
3040
Cfm
80.4
79.5
78.4
77.5
76.3
75.3
74.4
73.5
72.8
72.0
71.2
70.6
Note: Wtere toy of the first three rone from the extended-plenum exceeds 30 ft end 9 elbow*, count 3 extre elbow* for that run. tim Equivalent Length Values used end included in ~this table ere: Diffuser end Boot -- 100 ft; Eech Elbow -- 11 ft; Side Take-off = 10 ft.
Tapered Extanded-neaum Starting Collar.
Section D. Top Take-Off to 6-btdi Round Pipe for Baseboard Diffusers Only
Extended-Plenum Pressure 0.16 in. Static at 160 F
Furnace-Plenum Pressure 0.15 in. Static at 170 F
Actual length from Extended-Plenum to Piffvrer Feet
5 : 10 15 - 20 25 30 35 ' 40 45 . 50 55 60
0
1
2 3 4 5 '6
Btuh Cfm
Btuh Cfm
Btuh Cfm
Btuh Cfm
Btuh Cfm
Btuh Cfm
- Btuh Cfm
8700 95.0
8260 90.2
7880 86.3
7560 83.0
7260 80.0
7000 77.3
6770 74.6
8050 93.2
7640 88.8
7290 85.0
7000 82.0
6700 79.1
6470 76.3
6230 73.8
7450 91.7
6900 90.0
7090 87.5
6560 86.2
6750 6250 84.0 82.9
6470 81.0
5980 79.8
6200 78.1
5740 77.2
5970- 5490 75.4 74.5
5740 73.0
5290 72.2
6400 88.6
6080 85.0
5800 81.7
5540 79.0
5290 76.2
5070 73.8
4890 71.3
5910 8T.3
5630 83.7
5380 80.5
5130 78.0
4900 75.2
4700 72.8
4500 70.5
5470 86.0
5200 82.6
4980 79.6
4740 76.9
4510 74.3
4320 71.9
4140 69.8
5160 84.7
4820 81.7
4590 78.7
4380 76.0
4160 73.5
3990 71.2
3820 69.0
4670 83.5
4470 80.4
4260 77.6
4060 75.1
3850 72.7
3600 70.2
3520 68-3
4300 82.4
4140 79.4
3940 76.7
3730 74.2
3560 71.9
3400 69.3
3240 67.5
4000 81.3
3720 80.2
3830 78.4
3530 77.5
3620 75.8
3340 74.9
3430 73.3
3170 72.5
3290 71.0
3020 70.2
3120 68.7
2870 68.1
2980 - 2760 66.9 66.1
Note: Where any of the first three runs from tte extended-plenum exceeds 20 ft end 2 elbows, count 3 extra elbows for the! run. The Equivalent Length Tmluee used |m| included in calculating this table era: Diffuser and Boot 100 ft; Eheh Elbow 14 ft; Top Tate-off Hit
Tapered Extended-Plenum Starting Collar.
wall For such systems, the combinations of parts selected as standard by the National Warm Air Heating and Air Con ditioning Association are shown in Tables 9 and 10.
A simplified method for selecting the combinations of branches, boots, stacks, and registers, is given in Manual 7 of the National Warm Air Heating and Air Conditioning Association.' In this method, the sizes of the branch ducts
are obtained from two tables giving their Btu capacities. The proper combination of parts for each branch can be deter mined if the following information is available.
1. Location of room, that is, whether on first or second story. 2. Actual horizontal length of duct from bonnet to boot, in feet. 3. Btu loss from room to be heated.
i
1
Warm Air Hearing Systems
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Table 6... - Heating Capacities and Cfm of Branch Ducts in Extended-Plenum Perimeter Systems (Concluded)
Section E. Side Take-Off to 6-tnch Rawed Pipe for Side-well end Boor Diffuser*
Extended-Plenum Pressure 0.16 *. Static at 160 P
Furnace-Plenum Pressure 0.15 in. Static at 170 P
Actual length from fxtcuded-flenun to Diffuser--Feet
5 10 15 20 25 30 35 40 45 50 55 60
0 Btuh Cfm
8600 7930 7310 6740 6230 123.2 120.0 116.8 114.0 111.4
1 Btuh Cfm
8560 117.4
7900 114.5
7290 112.1
6720 109.2
6200 107.0
5740 104.8
2 Btuh Cfm
8510 112.7
7890 110.0
7300 107.6
6740 105.3
6230 103.1
5750 101.0
5310 99.0
3 Btuh Cfm
8540 108.2
7900 105.8
7300 103.6
6780 101.5
6270 99.6
5800 97.8
5360 95.9
4960 94.0
.4
Btuh Cfm
8580 7970 104.0 101.9
7370 99.8
6820 97.8
6330 96.0
5850 94.5
5410 92.8
5000 91.1
4620 89.7
6 Btuh Cfm
8720 100.2
8080 98.3
7490 96.7
6940 6440 94.8 _ 93.0
5960 91.4
5490 90.0
5080 88.7
4690 87.2
4320 85.0
6
Btuh
8900
8240
7630
7060
6550
6070
5600
5190 : 4800
4430
4100
Cfm
97.0
95.1
93.4
91.9
90.2
88.8
87.3
86.2
85.0
83.8
82.6
Note: Wter* any of the firxt three mo* from tte extended-plenum exceed* 20 ft end 2 elbow*, count 2 extre elbow* for that run. The Equivalent Length ValtM wed and included in --1-wUtim this table are: Diffuser and Boot - 40 ft; Each Elbow = 14 ft; Side Tate-off -- 20 ft.
Tapered Extended-Plenum Starting Collar.
5800 109.1
5340 102.8
4960 97.4
4610 92.5
'4300 88.3
4020 84.7
3810 81.5
Soction F. Top Take-Off to 6-lnd) Round Pipe for Side-wall and Boor Diffuier*
Extended-Plenum Pressure O.tt in. Static at 160 F
Furnace-Plenum Pressure 0.15 in. Static at 170 F
Actual Length from Extended-Plenum to Diffuier -feet
5 10 15 20 25 30 35 40 45 50 55 60
0 Btuh Cfm
8430 *111.2
7800 108.8
7210 106.3
6660 104.4
6170 102.2
5700 100.2
5270 98.4
4910 96.7
1 Btuh Cfm
8450 107.2
7840 105.0
7250 102.8
6700 100.7
6210 98.9
5730 97.0
5300 95.1
4900 93.4
4560 91.9
2 Btuh Cfm
8530 7900 103.2 101.1
7320 6800 99.0 97.2
6280 95.4
5790 93.8
5350 92.1
4960 90.6
4590 89.0
4250 87.8
3 Btuh Cfm
8660 8020 99.7- 97.8
7430 96.0
6900 94.2'
6370 92.4
5900 90.8
5450 89.4
5030 88.0
4650 86.7
4300 85.3
3990 84.2
4
Btuh
8810 "8180 7580
7010
6500
6000
5550
5150
4750
4400
4070
3780
Cfm
96.0
94.4
92.8
91.2
89.7
88.0
86.8
85.7
84.3
83.1
82.0
81.1
5
Btuh
8390
7770
7200
6650
6160
5700
5280
4890
4500
4170
3840
3580
Cfm
91.4 -90.0
88.5
87.2
85.8
84.5
83.2
82.4
81.0
80.0
79.0
78.3
6
Btuh
7980
7380
6840
6340
6880
5430
5020
4650
4290
3970
3660
3400
Cfm
87.5 -88.2
85.0
83.8
82.5
81.4
80.2
79.4
78.3
77.3
76.3
75.6
Note: Where any of tte first three rhns from the extended-plenum exceed* 20 ft and 3 dhow* ecmnt 3 extre dhow* for that run.
The Equivalent
Value* used ^ included in caloalating this table are: Diffuser and Boot 40 ft; Each Elbow 14 ft; Top Take-off GOlt
Tkpercd Extended-Plenum Storting Cedar.
4. Equivalent lengths in feet of all fittings and of the register. Fig. 7 shows the values of equivalent lengths of fittings com monly used for domestic systems.
This simplified method is applicable to structures having heat losses not in excess of approximately 120,000 Btu per hour. The capacities shown in Tables 9 and 10 are bared upon the most reliable data pertaining to friction losses and temperature drops in ducts. They are also based upon a 100 deg temperature rise of the air, and a static pressure
available for overcoming friction losses in the external duct system alone of 050 in. of water. The use of this method requires that the fan in the fan-furnace assembly will be capable not only of overcoming the resistance of the external duct system alone, but also the resistances imposed by the
blower inlet, the filter, and the furnace casing. Tables 9 and 10 are applicable for the selection of both
warm air and return air branches. A depth of 8 in. has been adopted as the standard for trunk ducts, and where a branch