4. Covers and/or grates shall be left in place in the frames, for safety reasons, except
while work is being performed.
D. ACCESSORIES:
1. All accessories shall be installed in accordance with manufacturer's instructions.
2. Stubs shall be set accurately to the dimensions indicated on the drawings. Stubs
shall be sealed with suitable watertight plugs.
3.02 LEAKAGE TESTS:
A. Leakage tests shall be made by the Contractor and observed by the Engineer on each
manhole. The test shall be by vacuum or by water exfiltration as described below:
B. VACUUM TEST:
1. The vacuum test shall be conducted in accordance with ASTM C1244. Test results
will be judged by the length of time it takes for the applied vacuum to drop from 10
inches of mercury to 9 inches. If the time is less than that listed in Table 1 of ASTM
C1244, the manhole will have failed the test. Test times from Table 1 are excerpted
below.
TABLE | Minimum Test Times for Various Manhole Diameters
Diameter (Inches)
Depth (Feet) 48 60 72
Times (Seconds)
0-12 30 39 49
12-16 40 52 67
16-20 50 65 81
20-24 59 78 97
26-30 714 98 121
2. If the manhole fails the initial test, the Contractor shall locate the leaks and make
proper repairs. Leaks may be filled with a wet slurry of accepted quick setting
material. If the manhole should again fail the vacuum test, additional repairs shall be
made, and the manhole water tested as specified below.
C. WATER EXFILTRATION TEST:
1. After the manhole has been assembled in place, all lifting holes shall be filled and
pointed with an approved non-shrinking mortar. All pipes and other openings into the
manhole shall be suitably plugged and the plugs braced to prevent blow out. The test
shall be made prior to placing the shelf and invert. If the groundwater table has been
2019 Sewer Replacement Project Precast Manholes and Catch Basins
Nashua, NH 02631-7
