Document 37MMOZ61orQy4MzK585v6jv3

868 CHAPTER 50 1948. Guide Table 1. Demand Weights of Fixtures in Fixture Units3 Fixture or Group1* Occupancy Type op Supply Control Stall or wall urinal______________ Office, etc._______________ Faucet____ Flush^valve for closet-__ Weight in Fixture Units 10 5 10 5 3 2 4 4 3 4 6 3 1 2 2' 8 6 2 2 3 -3 For supply outlets likely to impose continuous demands, estimate continuous supply separately and add to total demand for fixtures. . b For fixtures not listed, weights may be assumed by comparing the fixture to a listed one using water in similar quantities and at similar rates. ' ... .. . * The given weights are for total demand. For fixtures with both hot and cold water supplies, the weights for maximum separate demands may be taken as the listed demand for the supply. Fig. 1. Estimate Curves for Demand Load No. 1 for system predominantly for flush valves. No. 2 for system predominantly for flush tanks. Water Services 869 Table 2. Performance Requirements of Water Meters Size In. Normal Test-Flow Limits GPM Minimum Test-Flow GPM a H i IX-------------------------- > 3 4 a 1 to 2 to . 3 to 5 to 20 34 53 100 . 8 to 160 16 to 315 28 to 500 48 to 1,000 i2 i*2 2 4 7 12 *.American Water Works Association Standards: Registration. The registration on the meter dial shall indicate the quantity recorded to be not less than 68 per cent nor more than 102 per .cent of the water actually passed through the meter while it is being tested at rates of flow within the specified limits herein under normal test flow limits: There shall be not less than 90 per cent of the actual flow recorded when a test is made at the rate of flow set forth under minimum test flow. serious extent, Fig. 5 may be used safely to estimate carrying capacity of copper tubing2. SIZING OF COLD WATER SUPPLY PIPING In order to apply the foregoing principles to the sizing of the supply pipes in the usual up-feed system, it is necessary to ascertain the minimum pressure in the street main, and from this should be subtracted the mini mum pressure required for the operation of the topmost fixture. (A pressure of 15 psi is ample for flush valves but reference should be made to the manufacturers' requirements. A minimum of 8 psi should be allowed for other fixtures.) The pressure differential thus obtained will be available for overcoming pressure losses in the distributing system and in overcoming the difference in elevation between the water main and the highest fixture. The pressure losses in the distributing system will consist of the pressure losses in the piping itself, the pressure losses in the pipe fittings, and the pressure losses in the water meter, if any. Estimated pressure losses for disc-type meters for various rates of flow are given in Fig. 6. Flow limits for disc-type meters, which may be regarded as the limits of recommended ranges in capacities, are given in Table 2. For information on other types of meters the manufacturers should be consulted. Table 3. Allowance in Equivalent Length of Pipe for Friction Loss in Valves and Threaded Fittings Diameter op Fitting In. 90 Deg Standard Ell Ft h~ - % 1 - ImK--- - . - .. 9. 2K------3. .. . 3H--------------- 4. . 5 6 i 2 2.5 3 4 5 7 8 10 12 14 17 20 Equivalent Length op Pipe for Various Fittings . 45 Deg Standard Ell Ft 0.6 1.2 1.5 1.8 2.4 3 4 5 6 7 8 10 12 90 Deg Side Tee Ft Coupling or Straight Run of Tee Ft 1.5 3 4 5 6 7 10 12 15 18 21 25 30 0.3 0.6 0.8 0.9 1.2 1.5 2 2.5 3 3.6 4.0 5 6 Gate Valve Ft 0.2 0.4 0.5 0.6 0.8 1.0 1.3 1.6 2 2.4 2.7 3.3 4 Globe Valve Ft 8 15 20 25 35 45 55 65 80 100 125 140 165 Angle Valve Ft 4 8 12 15 18 22 28 34 40 50 55 70 80