The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Plumbing Repairs And Utilities
Inspect all installations, alterations and repairs of supply connections to potable-water systems carefully for potentially dangerous connections. (See fig. 14.) These may be roughly classified under three heads: interconnections between two piping systems; fixtures having over rim supplies with inadequate air gaps; and fixtures having under rim water supply connections that may be- come submerged or partially submerged when the fixture is used.
a. INTKKCONNECTIONS. Avoid direct interconnections between piping system for potable water and any piping system that may carry nonpotable water. When potable water must be used as an emergency .supply for a fire-protection system, prevent reverse flow .by either of the following methods :
(1) Connect the two piping systems through a tank open to air. Connect tank directly to supply lines of fire-protection system and supply potable water to tank through a float valve or a manually operated valve. Install a safe air gap between potable-water supply outlet and flood level of tank.
(2) Connect the two piping systems with a backflow-protection unit built and operated to meet National, State, or municipal sanitary codes. This unit normally consists of hydraulically-operated valves, using the hydraulic-balance principle of operation. The valves open gradually, remaining fully open as long as pressure at valve inlet is greater than pressure at valve discharge. This unit also includes vacuum-breaker valves to prevent creation of a vacuum within either supply line. Maintain these valves in accordance with manufacturers' directions.
b. DANGEROUS OVERRIM SUPPLY OUTLETS
(I) Fixtures with over rim water supplies, such as lavatories, sinks, and laundry trays, are sometimes improperly installed so the supply outlet extends too near the rim to prevent back-siphon age from the fixture. Correct this by providing a safe air gap. (See figs. 12 and 13.)
(2) Hose connections and extensions are dangerous in bathtub hand sprays, kitchen sink sprays, mortuary tables, bedpan washers, dental-cuspidor saliva ejectors, or similar installations where the outlet end of the hose may be submerged in the contents of the fixture. (See (1) and 2, fig. 14.) Remove hose and its attachment if its use is not essential; if it is essential, install an approved, permanently attached backflow preventer between supply outlet and hose and above fixture rim.
