Upon completion of the sewer or a portion thereof, the Service Director shall require that the sewer be tested by means of a “low pressure air test for sanitary sewers” under the procedure known as the Ramsier Procedure. The procedure shall be as follows:
(a) Clean pipe to be tested by propelling snug fitting inflated rubber ball thru the pipe with water;
(b) Plug all pipe outlets with suitable test plugs. Brace each plug securely;
(c) If the pipe to be tested is submerged in ground water, insert a pipe probe by boring or jetting, into the backfilled material adjacent to the center of the pipe, and determine the pressure in the probe when air passes slowly through it. This is the back pressure due to ground water submerged over the end of the probe. All gauge pressures in the test should be increased by this amount;
(d) Add air slowly to the portion of the pipe installation under air test until the internal air pressure is raised to 4.0 PSIG.
(e) After an internal pressure of 4.0 PSIG is obtained, allow at least two minutes for air temperature to stabilize adding only the amount of air required to maintain pressure.
(f) When pressure decreases to 3.5 PSIG, start stop-watch. Determine the time in seconds that is required for the internal pressure to reach 2.5 PSIG. Minimum permissible pressure holding times for funs of single pipe diameter for the systems of four, six or eight-inch lateral in combination with trunk lines are indicated in the following table in seconds.
(Ord. 0-26-1978. Passed 7-17-78.)
NCPI AIR TEST TABLES MINIMUM HOLDING TIME IN SECONDS REQUIRED FOR PRESSURE TO DROP FROM 3.5 TO 2.5 PSIG. | ||||||||||||||
PIPE DIAMETER (inches) | ||||||||||||||
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 | 478 |
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 | |||||||||
275 | 48 | 109 | 194 | 283 | ||||||||||
300 | 53 | 119 | 211 | 283 | ||||||||||
350 | 62 | 139 | 227 | 283 | ||||||||||
400 | 70 | 158 | ||||||||||||
450 | 79 | 170 | ||||||||||||
500 | 88 | 170 | ||||||||||||
550 | 97 | 170 | ||||||||||||
600 | 106 | 170 | ||||||||||||
650 | 113 | 170 | 227 | 283 | 340 | 425 | 510 | 595 | 680 | 765 | 851 | 935 | 1020 | 1105 |
Note: To be used when testing one diameter only
(g) The air test may be dangerous if, because of ignorance or carelessness a line is improperly prepared. It is extremely important that the various plugs be installed and braced in such a way as to prevent blow outs. Inasmuch as a force of 250 pounds is exerted on an eight inch plug by an internal pipe pressure of five PSI, it should be realized that sudden expulsion of a poorly installed plug or of a plug that is partially deflated before the pipe pressure is released can be dangerous.
As a safety precaution, pressurizing equipment should include a regulator set at ten PSI to avoid over-pressurizing and damaging an otherwise acceptable line. No one shall be allowed in the manholes during testing.
(h) All sewer mains which will become part of the Municipal sewer system will be televised before acceptance by the Municipality. All television work will be done between eighteen to twenty-one months after the sewer has been installed at the contractors expense. A copy of the report will be given to the Service Director for his review.