ORD 1778 - Laserfiche WebLink

406.2 Minimum pipe size shall be 3/4 inch for copper or brass, and 3/4 inch for plastic (CPVC). 406.3 *To size piping for systems connected to a city water supply, the hydraulically calculated or pipe size method is approximate method is acceptable. 406.3.1.1 Establish system flow rate in accordance with Sec 9.401. 406.3.2 Determine water pressure in the street. 406.3.3 Select pipe sizes. 406.3.4 Deduct meter pressure. 406.3.5 Deduct pressure loss for elevation. (Building height above street feet x 0.434 = psi), (Building height above street in meters x 0.098 - bars). 406.3.6 Deduct pressure losses from city main to control valve by multiplying friction loss per foot by the total length(s) of pipe in feet (m). (Include all fittings). 406.3.7 Deduct pressure losses for piping within building by multiplying friction loss per foot by the total length in feet (m) of each size of pipe between the control valve, check valves, flow switch and the farthest sprinkler. 406.3.8 Deduct valve(s) and fitting pressure losses. Count the valves and fittings from the control valve to the farthest sprinkler. Determine the equivalent length for each valve and fitting as shown in Table IV and add these values to obtain the total equivalent length for each pipe size. 406.3.9 In multi-level buildings, these steps shall be repeated to size piping for each floor. 406.3.10 If the remaining pressure is less than the operating pressure established by the testing laboratory for the sprinkler being used, a redesign is necessary. If this pressure is higher than required, smaller piping may be used when justified by calculations. 406.3.11 The remaining piping shall be sized the same as the piping to the farthest sprinkler unless smaller sizes are justified by calculations. Exception: For sprinklered dwellings manufactured off site, the minimum pressure needed to satisfy the system design criteria on the system side of the meter shall be specified on a data plate by the manufacturer. 23