Design and Construction Standards - Tualatin Valley Water District

Water Mains Section 31. Straddle blocks shall be poured monolithically against the pipe and undisturbednative soil.2. Straddle blocks shall be poured around a minimum of two “Megalug stylefollowers” in accordance with Section 3.2.e.4 and installed per manufacturer’srecommendations.3. Ensure that no unrestrained joints exist between the straddle block and pipesections or fittings that are to be removed.4. Ensure concrete straddle blocks have cured sufficiently before removing pipesections or fittings or otherwise inducing a load on the straddle block.5. See Detail 200.3.4 Hydrostatic Testing, Flushing, and Disinfectiona. Hydrostatic Test1. All pipelines intended to carry potable water shall be tested and disinfected beforeplacing in service.2. The Contractor shall perform pressure and leakage tests on all newly laid pipe inaccordance with District Standards. The District Engineer or Inspector shall benotified a minimum of 24 hours prior to testing and shall monitor the tests.3. The extents of pipeline sections to be tested will be determined by the DistrictEngineer.4. The tests shall be conducted after the trench has been completely backfilled andcompacted.5. Equipment and Materials:i. Two approved graduated containers.ii. Pressure gauges measuring in two-pound increments to max test pressure.iii. Pump capable of providing adequate pressure for test procedure.iv. Suitable hose and suction as required.6. Test Procedurei. After the trench has been backfilled and compacted, fill the pipe with waterwith an approved method that protects the existing distribution systemfrom possible contamination. The new mains being testing shall remainisolated from the existing water system.ii. At the section of the line with the lowest elevation, use a pump to apply atest pressure of 150 psi or 1.5 times the normal working pressure,whichever is greater. Verify required static pressure with TVWD inspector.iii. Isolate the pump and hold the pressure in the line for 60 minutes, unlessotherwise directed by the District Engineer.iv. At the end of the test period, operate the pump until the test pressure isagain obtained.TVWD Water System Standards June 2012 Page 3-10