(a) Low Pressure Air Acceptance Test.
(1) The contractor shall furnish all equipment and personnel to conduct an acceptance test using low pressure air. The test shall be conducted after backfilling and under the supervision of the Superintendent.
(2) All branch fittings and ends of lateral stubs shall be securely plugged to withstand the internal test pressures. The section of line being tested shall also be securely plugged at each manhole. All stoppers shall be adequately braced when required.
(3) Air shall be slowly supplied to the plugged pipe line until the internal air pressure reaches 4.0 pounds per square inch greater than the average back pressure of any ground water that may submerge the pipe. At least two minutes shall be allowed for temperature stabilization before proceeding further.
(4) The rate of air loss shall then be determined by measuring the time interval required for the internal pressure to decrease from 3.5 to 2.5 pounds per square inch.
(5) The pipe line shall be considered acceptable if the time interval for the 1.0 PSI pressure drop is not less than the holding time listed in the following air test table.
Minimum holding time in seconds required for pressure to drop from 3.5 to 2.5 PSIG.
Pipe Diameter | ||||||||||||||
Length of line in feet | 4 | 6 | 8 | 10 | 12 | 15 | 18 | 21 | 24 | 27 | 30 | 33 | 36 | 39 |
25 | 4 | 10 | 18 | 28 | 40 | 62 | 89 | 121 | 158 | 200 | 248 | 299 | 356 | 418 |
50 | 9 | 20 | 35 | 55 | 79 | 124 | 178 | 243 | 317 | 401 | 495 | 599 | 713 | 837 |
75 | 13 | 30 | 53 | 83 | 119 | 186 | 267 | 364 | 475 | 601 | 743 | 898 | 1020 | 1105 |
100 | 18 | 40 | 70 | 110 | 158 | 248 | 356 | 485 | 634 | 765 | 851 | 935 | ||
125 | 22 | 50 | 88 | 138 | 198 | 309 | 446 | 595 | 680 | |||||
150 | 26 | 59 | 106 | 165 | 238 | 371 | 510 | |||||||
175 | 31 | 69 | 123 | 193 | 277 | 425 | ||||||||
200 | 35 | 79 | 141 | 220 | 317 | |||||||||
225 | 40 | 89 | 158 | 248 | 340 | |||||||||
250 | 44 | 99 | 176 | 275 | ||||||||||
275 | 48 | 109 | 194 | 283 | ||||||||||
300 | 53 | 119 | 211 | |||||||||||
350 | 62 | 139 | 227 | |||||||||||
400 | 70 | 158 | ||||||||||||
450 | 79 | 170 | ||||||||||||
500 | 88 | |||||||||||||
550 | 97 | |||||||||||||
600 | 106 | |||||||||||||
650 | 113 | 170 | 227 | 283 | 340 | 425 | 510 | 595 | 680 | 765 | 851 | 935 | 1020 | 1105 |
To be used in testing one diameter only.
(b) Exfiltration Acceptance Test.
(1) The contractor shall furnish all equipment including the water and personnel to conduct an acceptance test using water. The test shall be conducted after backfilling and under the supervision of the Superintendent.
(2) In the exfiltration test, the inlet end of the upstream and downstream manholes shall be closed with a watertight plug, and the sewer along with the upstream manhole shall be filled with water until the elevation of the water in the upstream manhole is two feet higher than the top of the pipe in the section being tested, or two feet above the existing ground water in the trench whichever is the higher elevation. The exfiltration will be determined by measuring the amount of water required to maintain the above stated water elevation for a period of one hour from the start of the test. The entire length of section to be tested shall be filled and maintained full of water for a period of approximately twenty- four hours prior to the start of the test.
(3) Leakage in excess of 200 gallons per inch diameter per mile of pipe per day when measured and tested by methods herein described on any section including manholes shall be deemed to unsatisfactory performance.
(4) The allowable leakage is based on a maximum difference in elevation of eight feet between the level of water at the upper manhole and the invert of the pipe being tested in the lower manhole. If the difference in elevation exceeds eight feet, the allowable leakage shall be increased five percent (5%) for each one foot in excess of eight feet.
(c) It is understood that each section, as above described, must be tested and determined by the Superintendent to conform to this section before such section or sections may become part of the City system. It is further understood that, if the leakage does not come within the limits specified, the owner or contractor will be required to do such work as may be necessary in order to insure conformance even to the extent of reconstructing the defective section or sections. The method of testing is at the direction of the Superintendent.
(d) Before any section of an abandoned sewer system may be put into use as part of the City system, it must be tested and accepted by the Superintendent as meeting requirements of this chapter.
(Ord. 12-2-74-A. Passed 1-20-75.)