In special circumstances, and at the request of the BOH, a low-pressure
air test shall be performed on sewer lines in accordance with the
following guidelines:
A. Low-pressure air shall be introduced into the sealed pipe line until
the internal air pressure reaches four psi or greater than the average
back pressure of any groundwater that may be over the pipe. At least
two minutes shall be allowed for the air pressure to stabilize.
B. The requirements shall be accomplished by performing the test as
follows: The time required in minutes for the pressure to decrease
from 3.5 to 2.5 psig (greater than the average back pressure of any
groundwater over the pipe) shall not be less than the time shown for
the given diameters in the following table:
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Table 1: Pipe Diameter in Inches/Minutes
|
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|
Inches
|
Minutes
|
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|
4
|
2.0
|
|
6
|
3.0
|
|
8
|
4.0
|