(a) General.
(1) City will determine if, and to what level, testing is required.
(2) Clean and flush pipe system of foreign matter prior to testing.
(3) Notify city a minimum of 48 hours prior to testing.
(4) Perform tests in the presence of city.
(5) Length of line to be tested at one time shall be subject to approval of city.
(6) Pipe sections shall not be accepted and placed into service until specified test limits have been met.
(7) Repair defects in the pipe system. Make repairs to the same standard as specified for the pipe system.
(8) Retest repaired sections until acceptance.
(9) Repair visible leaks regardless of the test results.
(b) Storm drainage.
(1) Test gravity lines between manholes or junction boxes.
(2) Light testing. Mains will be checked by city for displacement after the trench has been filled to two feet above the pipe and tamped as specified, and upon completion of the project. Test will be as follows:
a. A light will be flashed between the ends of the pipe section being tested.
b. If the illuminated interior shows any misalignment, or other defects as designated by city, defects shall be repaired.
(3) General.
a. Infiltration shall not exceed 100 gallons per inch of diameter, per mile of pipe, per 24 hours. City may require flow measurement for verification of infiltration.
b. Verify that maximum infiltration rate shall not be surpassed by air testing as follows.
(4) Low pressure air test.
a. Air testing of sewer mains shall conform to UNI-B-6 and the following requirements:
b. Perform initial air test when each section of main is complete, but prior to installation of service wyes. Test as construction proceeds.
c. Wet interior surfaces of porous pipe material prior to testing.
d. Safety.
1. Provide a superintendent who has experience in low-pressure air testing of gravity sewer mains.
2. Follow safety recommendations of air testing equipment manufacturer.
3. Properly brace sewer plugs during testing. Test plugs prior to use in air testing.
4. No one shall be allowed in manhole or trench when pipe is under pressure.
5. Pressurizing equipment shall include a regulator and a pressure relief valve, which are set no higher than 9 psig. Monitor gauges continuously to assure that the pressure does not exceed 9 psig.
e. Equipment.
1. Sewer plugs shall be specifically designed for low pressure air testing.
2. Use two separate air hoses.
i. One to connect the control panel to the sealed line for introducing the air.
ii. One from the sealed line to the control panel to provide constant monitoring of the air pressure in the line.
iii. If pneumatic plugs are used a separate line shall be used to inflate the plugs.
3. As a minimum the above ground air testing equipment shall include a shutoff valve, pressure regulating valve, pressure relief valve, input pressure gauge, and a continuous monitoring pressure gauge having a pressure range from 0 to at least 10 psig.
4. Continuous monitoring pressure gauge shall be at least 4 inches in diameter with minimum divisions of 0.10 psi and an accuracy of +/- 0.04 psi.
5. Monitoring gauges shall be subject to calibration as deemed necessary.
6. Air used for testing shall pass through a single above ground control panel.
f. Testing.
1. Groundwater determination. Immediately prior to each air test, determine groundwater level by a method acceptable to the Engineer. Adjust pressure used in air test in accordance with groundwater level.
2. Apply air slowly to the test section until the pressure reached is 4.0 psi plus an adjustment of 0.433 psi for each foot of ground water above the crown of the pipe. Internal air pressure, including adjustment for ground water, should never exceed 9.0 psi.
3. When the above-required pressure is reached, throttle air supply to maintain internal pressure for at least two minutes to permit stabilization.
4. When pressure has stabilized at required pressure, shut off air supply.
5. While observing the continuous monitoring pressure gauge, decrease pressure approximately 0.5 psi from required pressure.
6. At this reading timing shall commence with a stopwatch and allowed to run until pressure has dropped 1.0 psi or allowable time has lapsed. Line shall be “Acceptable” if the pressure drop does not exceed 1 psig in the time prescribed for the test in Standard Detail, Low Pressure Air Testing for Gravity Sewer Mains.
(Ord. of 11-7-16, No. 10-16)