Design Guide for Community Water Systems - The Water, Sanitation ...

f. Cables, power conduits, antenna brackets or similar devices shall beinstalled inside properly constructed conduits. Properly designed bracketsmust secure these to the storage structure.7.0.16. Disinfection of Unpressurized Finished Water Storage StructuresDisinfection of unpressurized finished water storage tanks and reservoirsfollowing construction, repairs, painting, or other maintenance shall be donein accordance with the latest edition of the AWWA Standard for Disinfectionof Water-Storage Facilities, AWWA C652.a. At least one sample shall be analyzed to indicate microbiologicallysatisfactory water before the facility is placed into operation.b. Disposal of chlorinated water from the tank shall be in accordance withMissouri Clean Water Commission requirements to protect aquatic life.7.1. Tanks and Reservoirs for Finished Water Storage7.1.1. Fire Protection.Public water supplies that provide fire protection shall have finished waterstorage tanks, reservoirs, and other facilities with sufficient capacity toprovide minimum design needed fire flow for the length of fire duration andshall provide adequate storage to meet diurnal peak flow with fire flow beingconsidered.a. The minimum allowable design needed fire flow and design supply workscapacity are 250 gallons per minute for a fire duration of two hours.b. Other commonly used design needed fire flows with the equivalent firedurations are listed in section 7.5.7.1.2. No Fire Protection.Public water supplies that do not provide the fire protection shall havesufficient finished water storage to meet the minimum design operatingpressure and flow for the diurnal flow pattern on the design maximum usageday with all well pumps, treatment plants, high service pumps, booster pumps,or other equipment that affect pressure and flow in operation. This can beachieved by the following methods:a. Provide finished water elevated storage with nominal capacity equal to orgreater than one day’s average demand. For standpipes, the volumeabove the elevation, which provides 20 psig at the tower base, shall becounted as nominal capacity. (This method does not requiredocumentation or estimation of diurnal flow pattern or design maximumday usage.)b. Provide ground level finished water storage with nominal capacity equalto or greater than one day’s average demand. Duplex high service pumpswith capacity capable of meeting design instantaneous peak flow with theAug. 29, 2003Page 139