Download AWWA standard for resilient-seated gate valves for water by American National Standards Institute.; American Water Works PDF

By American National Standards Institute.; American Water Works Association

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Extra info for AWWA standard for resilient-seated gate valves for water supply service

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The valve box should be installed so as not to transmit shock loads or stress to the valve. The valve box should be centered over the operating nut of the valve with the box cover flush with the surface of the finished area or such other level as directed by the owner. Valve boxes should be designed so that a traffic load on the top of the box is not transmitted to the valve. 3 Valves buried in unusually deep trenches should have special provisions for operating the valve. Either a riser on the stem to permit use of a normal key or a notation on valve records that a long key will be required.

5 Hydrostatic testing To prevent time lost searching for leaks, it is recommended that valve excavations not be backfilled until after pressure tests have been made. After installation, it is desirable t o hydrostatically test newly installed piping sections, including valves, at some pressure above the system design pressure. The test pressure should not exceed the rated working pressure of the valve. After the test, steps should be taken t o relieve any trapped pressure in the body of the valve.

Sec. 3 Aboveground Installations Valves installed aboveground or in a plant piping system should be supported and aligned to avoid damage to the valves. Valves should not be used to correct the misalignment of piping. Sec. 4 Inspection After installation and before pressurization of the valve, all pressure-containing bolting (bonnet, seal plate, packing gland, and end connections) should be inspected for adequate tightness to prevent leakage. In addition, an inspection should be made for adequate tightness of all tapped and plugged openings to the valve interior.

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