Infiltration/exfiltration testing.

A. All sanitary sewers or extensions to sanitary sewers, including manholes, shall satisfy requirements of a final infiltration test before they will be approved and wastewater flow permitted by the Chief Plant Operator and/or Superintendent of Sewers. The infiltration rate shall not exceed 35 gallons per 24 hours per mile per nominal diameter in inches. An exfiltration test may be substituted for the infiltration test; the same rate shall not be exceeded. The exfiltration test shall be performed by the applicant, under the supervision of the representative from the Town of Webster, who shall have the responsibility for making the proper and accurate measurements required.

The exfiltration test consists of filling the pipe with water to provide a head of at least five feet above the top of the pipe or five feet above groundwater, whichever is higher, at the highest point under test, and then measuring the loss of water, from the pipe section under test, by the amount of water which must be added to maintain the original level. However, under no circumstances shall the head at the downstream manhole exceed 10 feet or fill to within six inches of the top of the downstream manhole. Should this condition prevail, the test section must remain filled with water for at least 24 hours prior to taking any measurements.

Exfiltration shall be measured by the drop of water level in a standpipe with a closed bottom end, or in one of the sewer manholes serving the test section. When a standpipe and plug arrangement is used in the upper manhole in the test section, there shall be some positive method for releasing entrapped air prior to taking any measurements.B. Test section. The test section shall be as ordered or as approved, but in no event longer than 1,000 feet. In the case of the sewers laid on steep grades, the test length may be limited by the maximum allowable internal pressure on the pipe and joints at the lower end of the test section.

For purposes of determining the leakage rate of the test section, manholes shall be considered as sections of forty-eight-inch-diameter pipe, five feet long. The maximum allowable leakage rate for such a section is 1.1 gallons per 24 hours. If leakage exceeds the allowable rate, then necessary repairs or replacements shall be made, and the section retested.C. Test period. The test period during which the test measurements are taken shall not be less than two hours.D. Pipe lamping. Prior to testing, the section shall be lamped. Any length of pipe out of straight alignment shall be realigned.E. Deflection testing.

Also prior to testing, all plastic pipe in the test section shall be tested for deflection. Deflection testing shall involve the pulling of a rigid ball or mandrel, whose diameter is 95% of the pipe inside diameter, through the pipe. Any length of pipe with a deflection greater than 5% shall be replaced. The test section shall be flushed just prior to deflection testing. The test shall not be performed with a mechanical pull device.F. Low-pressure air testing alternative.(1) In lieu of hydrostatic testing (exfiltration or infiltration), low-pressure air testing may be employed. Low-pressure air tests shall conform to ASTM Specification C 828.

All sections to be tested shall be cleaned and flushed, and shall have been backfilled, prior to testing. Air shall be added until the internal pressure of the test section is raised to approximately 4.0 psig. The air pressure test shall be based on the time, measured in seconds, for the air pressure to drop from 3.5 psig to 2.5 psig.(2) Acceptance is based on limits tabulated in the "Specification Time Required for a 1.0 psig Pressure Drop" in the Uni-Bell PVC Pipe Association "Recommended Practice For Low-Pressure Air Testing of Installed Sewer Pipe."(3) Before pressure is applied to the line, all connections shall be firmly plugged.

Before the test period starts, the air shall be given sufficient time to cool to ambient temperature in the test section.(4) If the test section is below groundwater, the test pressure shall be increased by an amount sufficient to compensate for groundwater hydrostatic pressure; however, the test pressure shall not exceed 10 psi, or a lower pressure as required by the Commissioner of Public Works and/or the Chief Plant Operator and/or Superintendent of Sewers.(5) The pressure test gauge shall have been recently calibrated, and a copy of the calibration results shall be made available to the Commissioner of Public Works and/or the Chief Plant Operator and/or Superintendent of Sewers prior to testing.G.

Vacuum testing alternative.(1) In lieu of hydrostatic testing (exfiltration or infiltration), vacuum testing may be employed for testing of sewer lines and manholes. Sewer lines and manholes shall be tested separately. All sewer lines to be tested shall be cleaned and flushed, and shall have been backfilled, prior to testing. The vacuum test shall be based on the time, measured in sections, for the vacuum to decrease from 10 inches of mercury to nine inches of mercury for manholes, and from seven inches of mercury to six inches of mercury for sewers.(2) Acceptance of manholes is based on the following:Manhole Depth(feet)Manhole Diameter(feet)Time to Drop 1 inch Hg(10 inches to 9 inches)(seconds)10 or less412010 to 15415015 to 254180NOTES:For five-foot-diameter manholes, add 30 seconds to the times above.For six-foot-diameter manholes, add 60 seconds to the times above.(3) If the test on the manhole fails (the time is less than that tabulated above), necessary repairs shall be made and the test vacuum test repeated, until the manhole passes the test.(4) Acceptance of sewers (seven inches Hg to six inches Hg) is based on the time tabulated in the "Specification Time Required for a 0.5 psig Pressure Drop" in the Uni-Bell PVC Pipe Association "Recommended Practice for Low-Pressure Air Testing of Installed Sewer Pipe."(5) The vacuum test gauge shall have been recently calibrated, and a copy of the calibration results shall be made available to the Commissioner of Public Works and/or Chief Plant Operator and/or Superintendent of Sewers.