b) Check for pressure drop
If there is no drop in pressure then the test is deemed a success.
If the pressure drops then the leak must be located. See following page.
However, if there is a change in the ambient temperature between the pressurizing stage
and the time when you check for a drop in pressure then you will have to adjust your
calculations accordingly since a change of 1°C can account for a pressure change of
Compensating adjustment value:
(temperature at time of pressurizing – temperature at time of checking) × 0.01
Time of pressurizing: 4.00MPa 25°C
24 hours later: 3.95MPa 20°C
The pressure drop in such a case is deemed to be zero (successful test).
4.00 Mpa x 24hr
15 Mpa x 5min
0.3 Mpa x 3min