Document p2vzLbrma26w0Q240e58X6G8X

750 CHAPTER 56 1959. Guide FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT LENGTH Water Services FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT. LENGTH 751 Fig. 4.... Flow Chart for Fairly Rough Pipe1 been found, for example, that a 1-tn., 90-deg elbow introduces a loss equivalent to 22 ft of straight 1-in. pipe. Therefore, for each 1-in., 90-deg elbow, 22 ft of 1-in. pipe are added to the total length of 1-in. pipe. Estimated pressure losses for pipe fittings and valves in terms of equivalent pipe length are shown in Table 4. Table 5 lists the equivalent lengths for various special types of apparatus and fittings. The loss in water meters varies considerably with the design even in meters of the same nominal size. The values given in Table 5 are ample for the well-known meters now on the market. The water demand for hose bibbs or other large demand Fig. 5___ Flow Chart for Rough Pipe1 fixtures taken off the building main is frequently the cause of inadequate water supply to the upper floor of a building. This condition may be prevented by siring the distribution system so that the pressure drops from the street main to all fixtures are the same. It is good practice to maintain the building main of ample size (not less than l in. where possi ble) until all branches to hose bibbs have been connected. Where the street main pressure is excessive and a pressure reducing valve is used to prevent water hammer or excessive pressure at the fixtures, it is frequency desirable to connect hose bibbs ahead of the reducing valve. The principles involved in sizing either up-feed or down-