(A) Each manhole shall be visually inspected for leakage or evidence thereof. If the manhole shows leakage, it shall be repaired to the satisfaction of the town and reinspected and retested at the contractor’s expense.
(B) Manholes will be checked by the town after installation and again before the one-year warranty period ends. If manholes show signs of leakage, they shall be vacuum tested by an approved company and repaired at the contractor’s expense.
(C) The contractor shall test all manholes using the Standard Test Method for Concrete Sewer Manholes by the Negative Air pressure (Vacuum) Test.
(1) Scope.
(a) This section covers procedures for testing precast concrete manhole sections using the vacuum test method to demonstrate the integrity of the installed materials and the construction procedures. This test method is used for testing concrete manhole sections utilizing mortar, mastic, or gasketed joints and is intended to be used as a preliminary test to enable the contractor to demonstrate the condition of the concrete manholes prior to backfill. It may also be used to test manholes after backfilling; however, the contractor must correlate the testing with the connector supplier.
(b) This test method is the companion to metric Test Method C1244M; therefore no SI equivalents are shown in this test method.
(2) Reference documents.
(a) ASTM standards:
1. C822, Terminology Relating to Concrete Pipe and Related Products/2;
2. C924, Practice for Testing Concrete Pipe Sewer Lines by Low-pressure Air Test Method/2; and
3. C969, Practice for Infiltration and Exfiltration Acceptance Testing of Installed Precast Concrete Pipe Sewer Lines/2.
(b) This practice is under the jurisdiction of ASTM C-13 on concrete pipe, most recent edition.
(3) Procedures.
(a) 1. All lift holes and any pipes entering the manholes are to be plugged. A vacuum will then be drawn and the vacuum drop over a specified time period will be used to determine the acceptability of the manhole.
2. The test head shall be placed at the top of the manhole in accordance with the manufacturer’s recommendations.
3. A vacuum of 10 in. of mercury shall be drawn on the manhole, the valve on the vacuum line of the test head will be closed and the vacuum pump shut off. The time shall be measured for the vacuum to drop to 9 in. of mercury.
4. The manhole shall be considered to pass if the time for the vacuum reading to drop from 10 in. of mercury to 9 in. of mercury meets or exceeds the values indicated in Table D.
5. If the manhole fails the initial test, necessary repairs shall be made using an approved method. The manhole shall then be retested until a satisfactory test result is obtained.
(b) Use or failure of this vacuum test shall not preclude acceptance by appropriate water infiltration or exfiltration testing if approved by the town.
(Ord. 2019-8-26(A), passed 8-26-2019)