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Described below is the procedure for air testing sewer lines to demonstrate the integrity of the ' <br /> installed material and the construction methods. <br /> *Summary of Method-The section of the sewer line to be tested is plugged. Low-pressure air is <br /> introduced into the plugged line. The amount and rate of air loss is used to determine the <br /> acceptability of the section being tested. <br /> *,Preparation of the Sewer Line- Flush and clean the sewer line prior to testing, thus serving to ' <br /> wet the pipe surface as well as clean out any debris. A wetted interior pipe surface will produce <br /> more consistent results. Plug all pipe outlets to resist the test pressure. Give special attention <br /> to stoppers and laterals. Testing to include all completed sewers including sewer services if <br /> included as a part of the work. <br /> *Procedures - Determine the test duration for the section under test by computation from the <br /> applicable equations shown in ASTM C 828, or from prepared air test tables. The pressure- <br /> holding time is based on an average holding pressure of 3 psi (21 kPa)gage or a drop from 3.5 <br /> psi(24 kPa)to 2.5 psi(17 kPa)gage. <br /> Add air until the internal air pressure of the sewer line is raised to approximately 4.0 psi (28 kPa) ' <br /> gage. After an internal pressure of approximately 4.0 psig is obtained, allow time for the air <br /> pressure to stabilize. The pressure will normally show some drop until the temperature of the <br /> air in the test section stabilizes. <br /> When the pressure has stabilized and is at or above the starting test pressure of 3.5 psi (24 <br /> kPa)gage, commence the test. Before starting the test,the pressure may be allowed to drop to ' <br /> 3.5 psig. Record the drop in pressure for the test period. if the pressure has dropped more <br /> than 1.0 psi (7 kPa) gage during the test period, the line is presumed to have failed. The test <br /> may be discontinued when the prescribed test time has been completed even though the 1.0 ' <br /> prig drop has not occurred. <br /> *Safe -The air test may be dangerous if, because of lack of understanding or carelessness, a <br /> line is improperly prepared. ' <br /> It is extremely important that the various plugs be installed and braced in such a way as to <br /> prevent blowouts. Inasmuch as a force of 250 lb. (1112N)is exerted on an 8-in. (203-mm) plug ' <br /> by an internal pipe pressure of 5 psi (34 kPa), it should be realized that sudden expulsion of a <br /> poorly Installed plug or of a plug that is partially deflated before the pipe pressure is released <br /> can be dangerous. <br /> As a safety precaution, pressurizing equipment may Include a regulator or relief valve set at <br /> perhaps 10 psi (69 kPa)to avoid over-pressurizing and damaging an otherwise acceptable line. <br /> No one shall be allowed in the manholes during testing. <br /> * able-The air test table below has been prepared utilizing applicable equations from ASTM C <br /> 828. It is based on an allowable air loss of 0.003 0/min•ft2 of internal pipe surface, a maximum ' <br /> air loss per test section of 3.5 Amin and a minimum significant air loss per test section of 2.0 <br /> Amin. (Test sections of such length that an air loss of 3.5 Amin would be exceeded using <br /> the allowable loss of air per square foot of internal pipe surface may be tested in segments <br /> where total air loss would be between 2.0 and 3.5 ft 3/min.) It applies when testing one pipe <br /> SANITARY SEWER LINES: DETAILED SPECIFICATIONS FOR INSTALLATION SS-8 <br /> 10/15/49 <br />