Line Tightness Test

LINE TIGHTNESS TESTING works as follows :

  1. The line is taken out of service and pressurized. A drop in pressure over time, preferably one hour, suggests a possible leak.

  2. Suction lines are not pressurized very much during a tightness test (less than 15 pounds per square inch).

  3. Tightness tests must be conducted at least very 3 years.

  4. Most line tightness tests are preformed by a testing company; you just observe the test.

  5. Some tank tightness tests can be performed so as to include a tightness test of the connecting piping.

  6. For most tightness tests, no permanent equipment is installed.

  7. Line must be taken out of service for the test, ideally for several hours, to allow line to stabilize before the test.

  8. In the event of a trapped vapor pocket, it may not be possible to conduct a valid tightness test. There is no way to tell definitely before the test begins if this will be a problem. Longer more complicated piping runs with many risers and dead ends are more likely to have vapor pockets.

LEVEL OF LEAK DETECTION REQUIRED

For suction pipe: must detect leak as small as 0.1 g/hr

For pressurized pipe: must detect leak as small as 0.1 g/hr when line pressure is 1.5 times its normal operating pressure.

COST

When performed at the same time as a tank tightness test, a typical line tightness test costs about $50 - $100, depending on the length and complexity of the piping.

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