I.P.S. Pressure/Irrigation (P.I.P) Installation Guide - JM Eagle

5.4 Making Leakage Tests
The purpose of a leakage test is to establish that the section of line to be
tested—including all joints, fittings, and other appurtenances—will not leak
or that the leakage established is within the limits of the applicable leakage
allowance. Leakage, if any, is usually involved in joints at saddles, valves,
transition fittings, adaptors and not usually in pipe joints. Normal operating
pressure is usually applied for tests. This should be maintained as constant
as possible throughout the testing period. Measurement of the amount of
additional water pumped in during the test will provide a measurement of the
amount of leakage, if any. In setting up a section of line for testing, air relief
valves should be provided. Air trapped in the line during the test will affect
test results and can cause damage to the pipeline and/or injury to workers.
Generally, the engineer will establish the duration of the test, the allowable
leakage, and indicate the appropriate methods and procedures for testing.
If not, a two-hour test is recommended and the allowable leakage shall be
determined by the following formula:
L = (ND P) / 7400
L is the allowable leakage, in gallons per hour; N is the number of joints in
the length of pipeline tested; D is the nominal diameter of the pipe in inches;
and P is the average test pressure during the test in pounds per square inch
gauge (PSIG). Leakage values determined by the above formula are shown
in Table 7.
Consideration should be given to any valves isolating the test section. Many
waterworks valves are not designed for leak-proof operation. Leakage
through these valves can distort actual leakage figures.
IRRIGATION & I.P.S. PRESSURE INSTALLATION GUIDE
41