Document 06rpzeG77yp489gnYLry9qrvk

American. Society of Heating and Ventilating Engineers Guide, 1929 Table 5. Pipe Sizes for Underground Supply Mains Based on a Velocity of 10,000 Ft. per Minute--[Continued.) Gags Pressure Lb. Lb. Steam per Minute Total B.t.u. above 200 Deg. Fare, per Hr. Pips Loss B.t.u. per Hour, per Ft. Length Bare Covered (10% of Bare) Lb. Steam Condensed per Hour per Ft. Length 0 10 20 40 60 80 100 120 140 160 180 . 200 0 10 20 40 60 80 100 120 140 160 180 200 74.6 122 167 256 345 427 514 606 690 770 870 950 134 218 298 458 617 765 917 1080 1230 1375 1550 1700 6 in. Pipe 4,504,000 7,260,000 10,020,000 15,360,000 20,880,000 26,040,000 31,440,000 37,260,000 42,480,000 47,400,000 53,700,000 58,800,000 8 in. Pipe 7,980,000 12,960,000 17,940,000 27,540,000 37,560,000 46,680,000 56,160,000 66,480,000 75,300,000 84,600,000 95,400,000 105,600,000 585 719 852 1037 1186 1311 1428 1528 1620 1694 1785 1872 760.7 936.7 1109.5 1351 1543 1707 1859 1988 2107 2207 2325 2443 58.5 71.9 85.2 104 119 131 143 153 162 169 178 187 76.1 93.7 110.9 135.1 154.3 170.7 185.9 198.8 210.7 220.7 232.5 .244.3 0.0604 0.0755 0.0918 0.1135 0.1320 0.1470 0.1630 0.1760 0.1880 0.1980 0.2110 0.2230 0.0785 0.0985 0.118 0.147 0.171 0.191 0.212 0.229 0.244 0.258 0.275 0.291 0 10 20 40 60 80 100 120 140 160 180 200 0. 10 20 40 60 80 100 120 140 160 180 200 211 345 '474 730983 1210 1455 1670 1960 2180 2470 2700 297 485 664 1020 1372 1700 2040 2410 2750 3060 3460 3800 10 in. Pipe 12,420,000 19,520,000 28,380,000 43,860,000 59,760,000 73,800,000 89,100,000 102,600,000 120,600,000 134,400,000 152,400,000 166,800,000 949 1170 1384 1685 1927 2132 2322 2486 2635 2755 \ 2903 3051 12 in. Pipe 17,460,000 28,860,000 39,900,000 62,100,000 83,400,000 103,800,000 124,800,000 148,200,000 169,200,000 182,400,000 213,600,000 235,200,000 1125 1387 1641 1999 2240 2529 2753 2945 3121 3266 3440 3616 94.9 117.0 138.4 168.5 192.7 213.2 232.2 248.6 263.5 275.5 290.3 305.1 0.0978 0.1230 0.1480 0.1840 0.2130 0.2390 0.264 0.286 0.306 0.323 0.343 0.364 112.5 ' _138.7 cf64.1 199.9 224.0 252.9 275.3 294.5 312.1 326.6 344.0 361.6 ; 0.116 0.146 0.175 0.218 0.248 0.284 0.314 0.340 0.362 0.383 0.406 0.430 210 Chapter XI--Central Heating Systems The offset lengths which are required for expansion in the case of wrought iron pipe may also be used for brass pipes, using in each case the actual amount of expansion in the piping. CAPACITY OF RETURNS WITH VARIOUS GRADES In general, return lines when installed follow the contour of the land and Table 3 gives sizes of return pipes'for various grades. It is evident that at points where the grade is great, smaller pipes can be installed. Table 4 gives the number of pounds of steam condensed to water for various steam pressures which can be used in determining the size of steam main or return line. Table 5 gives the capacity of various sizes of pipes under various steam velocity of 10,000 ft. per minute. The pipe loss will not vary under other velocities. For other velocities, the capacity may be determined by dividing by 10,000 and multiplying by actual velocity. HEATING CONDUITS Conduits for steam pipes buried underground should be water-proof, able to withstand earth loads and take care of the expansion and con traction of the piping without strain or stress on the couplings, also without affecting the installation or conduit. Expansion of the piping must be carefully controlled by means of anchors and expansion joints or betids so that the pipes can never come in contact with the conduit. Anchors can be anchor fittings or U-shaped steel straps which partially encircle the pipes and are firmly bolted to a short length of structural steel set in concrete. In laying out conduits of this type the following points should be borne in mind: 1. The conduit should be laid out in successive straight runs between manholes or anchor pits. 2. An anchor should be placed wherever the line changes direction. 3. An expansion joint offset or bend should be placed between each two anchors. 4. Manholes should be provided at each expansion joint. Where slip joints are used manholes should be vented. 5. Branches should be taken off at or near an anchor. 6. If the distance between buildings is 150 ft. or less and the steam line contains high-pressure steam, it may be anchored in the basement of one building and allowed to expand into the basement of the second building. If the steam line contains low-pressure steam (up to 4-ib. pressure), this method may be used if buildings are 250 ft. or less apart. 7. If the distance between buildings is between 150 ft. and 300 ft. and the steam line contains high-pressure steam, the lines should be anchored midway between the buildings and allowed to expand into the basements of both buildings. If the steam line contains low-pressure steam this method may be used if buildings are between 250 ft. and 600 ft. apart. No manhole is required at the anchor, and a blind pit is all that is necessary. 8. For longer lines, manholes must be located according to judgment and depending upon the expansion value of'the type of expansion joint or bend that is used. The minimum number of manholes will be required when an expansion bend or 211 X