Design and Construction Standards - Tualatin Valley Water District

Valves and Valve Boxes Section 43. Wrap valve body in three layers of 8-mil polyethylene sheet secured withpolyethylene tape prior to backfilling.4. Jointsi. Joints shall conform to ANSI/AWWA C600. Valves shall be installed inaccordance with Standard Detail 3.ii. Faces of flanges shall be cleaned thoroughly before flanged joint isassembled. After cleaning, the gasket shall be inserted and the nutstightened uniformly around the flange.iii. After tightening nuts, three full threads shall be showing on the end of thebolt where it is exposed beyond the nut.iv. Joints shall be tested with the adjacent pipeline for leakage. If joints leakunder test, valves shall be disconnected and reconnected, and the valveand/or pipeline retested.b. Gate and Butterfly Valve Boxes1. Center the valve boxes and set plumb over the wrench nuts of the valves. Valveboxes shall not rest on the valve body. Set the valve box covers flush with thesurface of the finished pavement.2. Cut extensions to the proper length so that the valve box does not ride on theextension when set at finished grade.3. Backfill shall be the same as specified for the adjacent pipe. Place backfill aroundthe valve boxes and thoroughly compact to a density equal to that of the adjacenttrench, avoiding damage to or displacement of the valve box. Misaligned valveboxes shall be excavated, centered, plumbed, and backfilled at the Contractor'sexpense.4. Where the valve is located in an unpaved area, the Contractor shall pour a concretepad around the valve box. The concrete shall be 24 inches square by 4 inchesthick, and shall be placed on a base of four inches of compacted crushed rock.Crushed rock shall meet the requirements of Section 2.2.b. Refer to Detail 3 forconcrete pad.5. Valve boxes shall be installed in conformance with Standard Detail 3.c. Air and Vacuum Release Valve Boxes1. Thoroughly compact the gravel beneath the concrete box and set the box so that itconforms to the elevation of the ground.2. Place at least 12 inches of crushed rock beneath the air release valve. Crushedrock shall meet the requirements of Section 2.2.b.3. Allow at least six inches of clearance between the street ell and the box top.4. Test and disinfect air valve assemblies in conjunction with the pipeline.TVWD Water System Standards June 2012 Page 4-5