Document nkkkMZOJYX7MnrYQLGeBYEQz1

438 CHAPTER 21 , 1949 Guide v /r-'* 1 </fatal shield ex- tenting Of beyond casing ";-:y 0\j--Ov.\r Girth'S 1 ' ^ z-~-a---ir space- open. Insulated with airspace or cov ered with magne sia, asbestos, or sand Inner finer-from fop cosing ring to grate level ffetof casing Fio. 3. Details of Fubnace Bonnet, Casino, and Foundation (Fbom Gbavity Code and Manual) The selected types of boots are shown in Fig. 2 and their resistances ex pressed in equivalent elbows are shown in Table 5. It is essential that free areas, be maintained- throughout fittings. Figs. 3 and 4 show recommended practice as given.in the N.W.A.H. & A.C. Assn. For construction; design features, and ratings of gravity ' furnaces see Chapter 18. Carrying- Capacity The: Btu carrying capacities of the selected warm air and return air 1 combinations are shown-in Tables 6, 7 and 8. The selected types of return air ducts and fittings are shown in Fig. 5. z* or /el fillJoints taped with \ asbestos paper ''Tight collar Insulated with 3 layers of air cellasbestos paper whenpipe passes thru unheaTed space. Fig. 4. Details op Bonnet and Lbadeb op Gbavity Warm-Aib Fubnace yj (Fbom Gravity Code and Manual) "Gravity^Warm Air Systems 439 Table 6. -Warm AibCarryingCapacity.BtuDelivered,First Story Registers* Length of Leader Pipe--in Feet . Combi nation No. No. OF Elbows 4 FT 6 Ft 8 Ft 10 Ft 12 Ft 14 FT 16 Ft 18 Ft 20 Ft 22 Ft 24 Ft 1 2 3 4 5 1 2 3 4 5 1 2 34 5 1 2 3 4 5 1 2' 3 4 5 6.020 5,850 5,680 5,510 5,340 5,170 5,000 4,830 4,660 4,490 4,320 7.620 7.400 7.180 6,970 6,760 6,540 6,320 6,110 5,890 5,680 5.460 1 9.400 9,140 8,870 8,600 8.340 8,070 7,810 7,540 7,270 7.010 6,740 13,350 12.970 12.590 12,210 11,830 11,450 11,080 10,700 10,320 9.950 9,560 17,520 17,020 16,530 16,040 15.550 15,050 14,550 14,050 13,560 13,060 12,560 5.850 5.660 5,490. 5.330 5,160 5,000 4.840 4,670 4,510 4.340 4,180 7,360 7,150 *6,940 6,730 6,520 6.320 6.110 5.910 5,700 5,500 5,290 2 - 9,090 8,840 8,580 8.320 8,060 7.800 7,550 7.290 7.040 6.780 6,520 12,910 12,540 12,170 11,800 11,430 11,060 10,690 10.320 9.950 9,580 9,210 16,940 16,450 15,990 15,500 15,040 14,550 14,080 13.600 13,120 12,650 12.150 5,020 5,460 5,310 5,150 4.990 4,830 4,670 4.510 4.350 4,190 4.030 7,120 6,910 6,710 6.510 6,310 6.110 5.900 5.700 5.500 5.300 5,100 3 8,780 8,530 8.280 8.030 7.780 7.530 7,290 7,040 6.800 6.550 6.300 12,450 12,100 11.750 11,400 11,050 10.700 10.350 10,000 9.650 9,300 8.950 16,360 15,900 15,440 14,970 14,510 14,050 13.600 13,130 12,600 12,200 11,750 5,420 5.260 5,110 4,960 4,800 4.650 4,500 4.350 4.190 4,040 3.890 6.860 6,660 6,460 6,270 6,080 5.890 5.690 5.500 5,300 5,110 4,910 4 8,460 8,200 7.980 7.740 7.500 7.260 7.020 6.780 6,550 6,310 6.070 12,010 11,670 11,330 10,990 10,650 10.310 9,970 9,630 9.290 8,950 8.610 15,770 15,320 14.8S0 14.420 13,990 13.540 13.100 12,650 12.200 11.750 11,310 5,240 5,090 4,940* 4,790 4,640 4,500 4,350 4,200 4.050 3,910 3.760 6,630 `6.440 6,250 6,060 5.880 5,690 5,500 5.320 5,130 4,940 .4,750 5 . 8,180 7.950 7,720 7.490 .7.260 7,030 6,800 6,560 6,330 6,100 5.860 11,610 11,290 10,950 10,620 10.300 9,970 9.640 9.320 8,990 8.660 8,320 15;2S0 14,800 14.380 13,950 13,520 13.090 12,650 12,230 11,800 11,370 10.940 Additional values for 6 and 7 elbows are given in original Manual.' Table 7. Warm Air Carrying Capacity,- Btu Delivered, Second Story Registers* Length of Leader Pipe--in Feet Combi nation No. b. No. OF Elbows 4 Ft 6 Ft 8 Ft 10 Ft 12 Ft 14 Ft 16 Ft 18 Ft 20 Ft 22 Ft 24 Ft 11-22 12-24 14 15 16 11-22 1&24 14 15 16- 12-24 15 16 11-22 ' 12-24 15 16 11-22 14 16 . 8.370 8.140 7,900 7,670 7,430 7.190 6,950 6.710 6.470 6,240 6,000 10,040 9,760 9,470 9; 190 8.900 8.620 8,330 8,050 7,770 7.480 7.200 1 11,710 11.380 11,050 10,720 10,390 10.060 9.720 9,390 9,060 8,730 8.400 16,200 15.750 15,300 14,840 14,380 13.920 13.460 13.000 12,550 12,100 11.640 18,920 18.390 17,850 17,310 16.780 16,240 15.710 15,180 14,640 14,100 13,670 7.940 7.720 7.600 7.280 7,050 6,830 6,600 6,370 6,150 5.930 6.700 9,540 9,270 9.000 8.730 8,460 8,190 7,920 7,650 7,380 7,110 6,840 2 11,120 10.810 10.500 10,180 9.870 9.550 9,230 8,920 8,610 8.290 7,980 15,400 14.970 14,530 14,100 13.670 13,230 12,800 12,360 11.930 11.500 11,070 17,980 17.470 16,960 18,450 15.950 15,430 14.830 14,420 13,910 13,400 12,890 7,530 7,320 7,110 6.900 6,680 6.470 6,250 6.040 5,830 5.620 5,400 9,030 8.780 8,520 8,270 8.010 7.750 7,500 7,240 6,990 6.730 6,470 3 10,530 10,240 9,940 9.650 9.350 9,050 8,750 8.450 8.160 7.860 7,560 14.580 14.180 13,780 13,370 12.950 12,530 12,120 11,710 11,300 10.890 10,480 17,040 16,550 16,070 15,580 15,110 14,620 14,140 13,660 13,180 12.700 12.210 7,120 6,920 6,720 6,520 6,310 6.110 5.900 5,700 5.500 5.300 5.100 8.530 8,290 8,050 7.810 7,570 7.330 7.080 6.840 6,600 6,360 6,120 4 9.950 9,670 9,390 9.110 8,830 8.550 8.260 7,980 7.700 7,420 7,140 13,780 13,390 13,000 12.610 12.220 11.830 11,440 11.050 10,670 10.280 9.890 16,080 15,620 15,170 14,710 14,260 13.810 13,350 12,900 12,440 11,980 11,530 6,700 6.510 6.320 6,130 5,940 5.750 5,560 5,370 5,180 4,990 4,800 8,040 7.810 7,580 7,350 7.130 8.900 6.670 6,440 6,220 5,990 5,760 5 9,370 9,110 8,850 8,580 8.310 8.050 7.780 7.510 7,250 6.980 6,720 12,970 12.600 12,240 11,870 11,500 11,140 10.770 10.400 10,040 9.680 9,310 15,140 14.710 14.280 13,850 13,420 13,000 12,570 12.140 11,710 11,280 10,850 * When floor registers are used, see Fig. 2. b No. 21 for Btu values multiply 11-22 values by 0.83. * No. 23 for Btu values multiply 12-24 values by 0.83.