(a) Supervision.
(1) All sewers must be tested by the contractor under the supervision of the Engineer prior to acceptance by the owner.
(2) Test for the owner's acceptance must be conducted at least 30 days after the full backfill is placed, although the contractor is free to conduct his own unofficial test prior to that time. The cost of testing is paid for in the price bid for pipe.
(3) If the tests are not passed, the contractor shall be required to locate and remedy the defects in construction causing the infiltration and/or deflection; and the test shall be performed again on any section failing the initial infiltration and/or deflection test. Sections, or the system will not be conditionally accepted, until a satisfactory infiltration and/or deflection result is obtained.
(4) It is understood that each manhole to manhole section must be tested and determined by the Engineer to conform to requirements of the specifications before the section is included in the month estimate at full contract price. It is further understood that if the tests do not fall within the limits specified, the Contractor will be required to do such work as may be necessary to insure conformance even to the extent of reconstruction of the defective section or sections.
(5) All visible leakage in sewers or manholes shall be repaired, even though tests may have been satisfactory.
(b) Gravity Sewers.
(1) All gravity sewers will be tested by the low pressure air exfiltration leakage methods.
(2) In all subsequent references to test pressure, a pressure adjustment shall be made where ground water is above the sewer line being tested, by adding 0.433 psi pressure for each foot the ground water level is above the invert of the pipe, based upon the maximum for the test section. The contractor shall make provisions for determining the ground water level and the level shall be confirmed by the engineer.
(3) Test procedures shall be as follows: The section of pipe to be tested shall be plugged at each end. The ends of all branches, wyes, and laterals shall be sealed or plugged. All plugs shall be braced to prevent slippage or blowout. One of the plugs provided shall have an inlet tap or other provision for connection of an air hose.
(4) Connect one end of the air hose to the inlet tap on the plug and the other end to portable air control equipment, which shall consist of pressure gauges and valves to control the rate at which air flows into the test section and to monitor the air pressure within the test section. Pressure gauges shall have minimum graduations of 0.1 psi and an accuracy of plus or minus 0.04 psi. The air control equipment shall be connected to a source of air supply such as an air compressor.
(5) Air shall be applied slowly to the test section until the pressure reaches four psig (pounds per square inch, gauge), plus adjustment for ground water. The pressure inside the pipe shall not exceed five psig, plus adjustment for ground water When the pressure inside the test section reaches 4.0 psig, the air pressure shall be throttled so that the internal pressure is maintained between 4.0 and 3.5 psig for at least two minutes to permit temperature stabilization.
(6) Upon expiration of the two minute period, the air supply shall be shut off or disconnected and the pressure allowed to drop to exactly 3.5 psig. At the exact time 3.5 psig is reached, a stop watch shall be started and the time required to drop exactly 2.5 psig shall be determined.
(7) Make proper pressure adjustments for ground water, where applicable, in determining the beginning and end of the period for the 1.0 psig pressure drop. The permissible time allocation for the 1.0 psig pressure drop shall be calculated on the basis of the diameter and length of the main sewer tested and no adjustment shall be made for service connections included in the test.
(8) The air test for the test section shall be considered acceptable if the time elapsed for the 1.0 psig pressure drop, as previously specified, is equal to or greater than the time, in minutes, indicated on the following table:
Length of Main Line Tester
Pipe diameter (inches) | 100 Feet | 200 Feet | 300 Feet | 400 Feet | 500 Feet | 600 Feet |
6 | 2 | 2 | 2 | 2-2/3 | 4-1/3 | 5 |
8 | 4 | 4 | 4 | 5-1/4 | 6-1/2 | 7-3/4 |
10 | 4-3/4 | 4-3/4 | 7 | 8 | 10 | 12 |
12 | 5-3/4 | 5-3/4 | 8-3/4 | 11-1/2 | 14-1/2 | 17-1/4 |
15 | 7-1/4 | 9 | 13-1/2 | 18 | 22-1/4 | 26-3/4 |
18 | 8-1/2 | 13 | 19-1/4 | 25-3/4 | 32-1/4 | 38-1/2 |
21 | 10 | 17-1/2 | 36-1/4 | 35 | 43-3/4 | 52-1/2 |
24 | 13 | 23 | 34-1/2 | 46 | 57-1/2 | 69 |
(c) Time in Minutes.
(1) Time for intermediate lengths shall be interpolated.
(2) The air test shall be unacceptable if the elapsed time is less than the stated period, defects shall be corrected and the line retested. Unless the air test fails due to a leaking plug, a TV inspection of the test section shall be conducted to determine the cause of the failure, this shall be at the expense of the contractor.
(3) If an infiltration leakage test is used rather than an air test, the maximum rate of infiltration is 200 gallons per inch diameter per mile of pipe, per 24 hours. This test is to be conducted when the height of the ground water is four feet or more above the elevation of the crown of the pipe at the upstream and of the section of pipe to be tested. If the ground water does not provide sufficient head, the contractor shall flood the trench to obtain specified external head. The measuring device shall be V-notch weir or other measuring device approved by the engineer.
(4) All tests for acceptance shall be conducted with the engineer present. Safety precautions shall be carefully observed by the contractor during air testing, recognizing the danger from plugs blowing out and from loading the sewer line with the full pressure of the compressor. No one shall be allowed in manholes during testing.
(5) All sewers must be tested for infiltration. When this cannot be achieved in sections of sewers that are being replaced in the same trench as the existing sewers, and upon approval of the engineer, the lines must be televised internally to verify leakage points. Water head of at least four feet must be applied over the sewer during this procedure. Televising shall be limited to periods between midnight and 6:00 a.m. Leaking points must be repaired as previously explained. This process may not be substituted in areas where air or leakage tests are feasible.
(d) Deflection Test.
(1) If PVC or ABS pipe is used deflection tests will be run not less than thirty days after final full backfill has been placed. The test required on all PVC and ABS pipe deeper than twelve feet at points between two manholes and at depths shallower than twelve feet if the pipe has a stiffness of less than 200 psi.
(2) Where possible, electronic equipment shall be used to measure and record the deflection in flexible pipe. No pipe shall exceed a deflection of 5%.
(3) If such equipment is not available, the deflection test can be run by use of mandrels, having a diameter equal to 95% of the inside diameter of the pipe pulled through the sewer line without mechanical pulling devices. Mandrels shall be constructed with at least nine evenly spaced arms or prongs. A metal proving ring shall be provided to verify the accuracy of the mandrel to the Engineer. The contractor length of the mandrel shall be eight inches for eight-inch pipe, and ten inches for ten-inch and twelve-inch pipe.
(4) If any section of conduit exceeds a deflection of five percent, it shall be the Contractor's responsibility to make the necessary corrections to the satisfaction of the engineer. The costs of all materials, equipment, labor, and all incidentals necessary for making the deflection test and for making any necessary corrections or replacement shall be included in the price of the pipe. The deflection test is required to conditional and final acceptance. At the discretion of the engineer, it may be required that the PVC and ABS sewers be tested for deflection before expiration of the one-year maintenance bond. A conduit, which has deflected more than 5%, must be corrected to the satisfaction of the engineer by the contractor.
(e) Force Main Testing.
(1) A leakage test shall be applied to all force mains. The force main shall remain isolated from adjacent force mains and a pressure of at least 100 pounds per square inch shall be applied by pumping clean water from a clean container through one-inch corporation stops installed in the ends of the force main, with the contractor to provide an initial pressure of 110-120 psi.
(2) The pressure test shall be in an afternoon and the pressure shall be on for eighteen hours and then the pressure shall be maintained at 100 psi or more for an additional six hours by pumping water from the container. A minimum test pressure of 100 psi shall be assured by pumping until a pressure 110-120 psi is attained. At the end of the six-hour period the water used shall be measured and the loss by leakage shall not exceed 75 gallons per inch diameter per mile of pipe per 24 hours.
(3) If the force main does not pass the leakage test, the leaks shall be located and repaired and the testing procedure repeated.
(4) The cost of furnishing all material, labor, equipment and the total volume of water for testing is included in the price of the force main.
(Ord. 89-15. Passed 6-19-89.)