(a) General.
(1) Clean and flush pipe system of foreign matter prior to testing.
(2) Notify the city a minimum of 48 hours prior to testing.
(3) Perform tests in the presence of the city.
(4) Length of line to be tested at one time shall be subject to approval of the city.
(5) Pipe sections shall not be accepted and placed into service until specified test limits have been met.
(6) Repair defects in the pipe system. Make repairs to the same standard as specified for the pipe system.
(7) Retest repaired sections until acceptance.
(8) Repair visible leaks regardless of the test results.
(b) Pressure mains.
(1) The city shall approve the source, quality, and method of disposal of water to be used in test procedures.
(2) Obtain city's permission 48 hours prior to filling or flushing of pipe system with water from city's water system. City shall operate valves connected to the existing water system. Keep pipe interior clean during construction to minimize the amount of water required for flushing. Where large quantities of water may be required for flushing, city reserves the right to require that flushing be done at periods of low demand.
(3) Pressure test in accordance with AWWA C600 for ductile iron pipe and AWWA C605 and M23 for PVC pipe and the following.
(4) Make pressure tests between valves. Furnish suitable test plugs where line ends in “free flow.”
(5) Provide air vents at the high points in the line section to be tested for releasing of air during filling. Service corporation stops may be used for air vent when located at a high point. Leave corporation stops in place after testing and note locations on as-constructed drawings.
(6) Allow concrete blocking to reach design strength prior to pressure testing.
(7) Force main shall be completely filled with water, all air expelled from the pipe, and the discharge end of the pipeline shall be plugged and adequately blocked before hydrostatic test begins.
(8) Upon completing a section of pipe between valves, test pipe by maintaining for a two hour period a hydrostatic pressure equal to 1.5 times the system working pressure or 150 psi, whichever is greater.
(9) Test pressure shall not vary by more than +/- 5 psi for the duration of the test.
(10) No length of line shall be accepted if the leakage is greater than that determined by the following formula based on the appropriate test pressure:
a. L = Allowable leakage per 1,000 feet of pipe in gallons per hour.
b. D = Nominal diameter of the pipe in inches.
c. 100 psi: L = D x 0.07.
d. 150 psi: L = D x 0.08.
e. 200 psi: L = D x 0.09.
f. 250 psi: L = D x 0.10.
(c) Gravity sewer mains.
(1) Test gravity lines between manholes.
(2) Light testing. City will check for displacement of pipe as follows:
a. A light will be flashed between the ends of the pipe section being tested.
b. If the illuminated interior shows misalignment, or other defects as designated by the 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. Engineer 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 including services to right-of-way. 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 four inches in diameter with minimum divisions of 0.10 psi and an accuracy of +1- 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 stop watch 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, S-1.21, Low Pressure Air Testing for Gravity Sewer Mains.
(5) Deflection test for SDR 35 and C-900 PVC Pipe.
a. Measure for deflection of pipe no sooner than 30 days after installation and backfill.
b. Deflection shall not exceed 5% of pipe diameter. Maximum allowable long term deflection shall be 5%.
c. Measure deflection with an approved “GO-NO-GO GAUGE” method or by an approved recording deflectometer. Verify gauge on site prior to testing.
(6) When gravity sewer mains do not meet the required minimum separation from wells, water mains or streams, hydrostatic testing shall be performed as follows:
a. The source, quality, and method of disposal of water to be used in test procedures shall be approved by the city.
b. Obtain city's permission 48 hours prior to filling or flushing of pipe system with water from city's water system. City shall operate valves connected to the existing water system.
c. Air test line, as described above, prior to hydrostatic testing.
d. Provide taps for filling and pressurizing the line. Service corporation stops may be used. Include cost of taps in price of testing. Leave corporation stops in place after testing and note locations on As-constructed drawings.
e. Suitable means for thrust restraint shall be installed for testing.
f. Test for each manhole reach.
g. Test pipe by maintaining for a two-hour period a hydrostatic pressure of 150 psig.
h. Test pressure shall not vary by more than +/- 5 psi for the duration of the test.
i. Pressure test in accordance with AWWA C600 for ductile iron pipe and as described above.
(Ord. of 11-7-16, No. 10-16)