lowing table, town pressures may be readily brought to feet of head, and the results ascertained. 70 30.32 28.15 IIO 47.64 155 66.27 198 66.70 84.90 85 33 85.76 241 104.39 242 104.83 199 86.20 67.14 200 243 105.26 244 105.69 86.63 245 106.13 67.57 201 87.07 246 106 56 157 68.00 202 87.50 247 106.99 158 68.43 203 87.93 248 107.43 159 68.87 204 69.31 116 50.24 89.23 251 108.73 117 50.68 207 89.66 252 109.16 118 51.11 163 70.61 208 90.10 253 109.59 119 51.54 164 71.04 209 90.53 254 110.03 120 51.98 165 71.47 210 90.96 255 110.46 121 52.41 166 71.91 211 91.39 256 110.89 33.35 122 52.84 167 72.34 212 91.83 257 111.32 33.78 123 53.28 168 72.77 213 92.26 258 111.76 79 34.21 124 53.71 169 73.20 214 92.69 259 112.19 80 34.65 125 54.15 170 73.64 215 93.13 260 112.62 81 35.08 126 54.58 171 74.07 216 93.56 261 113.06 16.02 82 35.52 127 55.01 172 74.50 217 93.99 262 113.49 16.45 83 35.95 128 55.44 74.94 218 94.43 263 113.92 16.89 84 36.39 129 55.88 174 75.37 219 94.86 264 114.36 40 17.32 85 36.82 130 56.31 175 75.80 220 95.30 265 114.79 17.75 86 37.25 131 56.74 176 76.23 221 95.73 266 115.22 18.19 87 37.68 132 57.18 177 76.67 222 96.16 267 115.66 88 38.12 133 57.61 178 77.IC 223 96.60 268 116.09 44 19.05 89 38.55 134 58.04 179 77.53 224 97.03 269 116.52 90 39.98 135 58.48 180 77.97 225 97.46 270 116.96 173 Head in feet x .433 lbs. per square inch; and inversely, pounds per square inch x 2.3 feet of head. Areas.-Areas of pump plungers or pipes of different diameters, and the gallons displaced in every foot 205 88.36 249 107.86 88.80 250 108.29 of travel, or contained in a foot length of pipe, are given below: The above table also answers for cubic contents of pipe. Thus a pipe 10 inches diameter contains 3.393 imperial gallons in a foot length, which result multiplied by 10 gives lbs. weight of water, or being divided by 6.23 is turned into cubic feet. Jets. A table of the delivery of water in jets or fire streams. Giving pressure at nozzle, with quantity and pressure necessary to throw good effective streams various distances through different size nozzles, using 100 feet of ordinary 24-inch rubber-lined hose and smooth nozzles. N. B. The above pressures are based on the supposition that the hose is coupled direct to the stream flowing; if, however, the hose is coupled to a long pipe, then an allowance must be made of an amount equal to friction loss. See succeeding table of losses by friction. The pressures given are indicated pressures, not effective pressures. fective pressures would be slightly greater. Ef The distances given are for effective fire streams adapted for fire purposes, and are not for mere isolated drops. 66 Discharge. A table of the cubic feet discharged through an ordinary orifice, not like a fire-jet or what is technically known as a vena-contracta," but such as a mill-gate or shuttle, under a direct head of water immediately above it. The following amounts are 64 per cent. of the theoretical, and are correct for all parallel openings, such as those cut in planks, mill-races, etc. The Measurement of a Water Supply Derived from Pipes. -In estimating the results to be derived from a town supply it is not sufficient to take into account merely the known head or fall of the system, as the loss due to friction in the pipes is a considerable item to be deducted, and is very greatly increased by bends or turns in the pipes or by restriction in size at any part of the passage. An immense amount of calculation has been devoted to the settlement of the results of water flowing in pipes. In the case of a town supply it is naturally very difficult for a consumer to ascertain the real conditions under which his supply reaches him, and he can reach a conclusion best by measuring the amount delivered at his tap in a given period, and then by attaching a pressure-gauge by means of a temporary joint he may ascertain the pressure. From 10 to 12 feet of head is absorbed in friction per mile of pipe. |