In brief
- A pressure test only proves the pipe if a supervisor watches the gauge, records the pressure at the start and end of the hold, and walks the line while it is under pressure.
- Undetected installation defects, such as a dry joint or a fitting pushed home without solvent, pass a short test and leak months later once the trench is backfilled.
- The client can close the gap by holding the test before backfill, asking for the gauge readings in writing, and checking the joint log against the delivered pipe.
Contents
A crew fills the pipe, watches the gauge for a few minutes, and backfills the same afternoon. The problem sits in the record that was never kept, not in the pipe itself. Make the test something you can read back: who watched the gauge, what it said at the start and the end, and how long the trench stayed open.
Why does the test pass before the defect shows?
A line can hold pressure for a short hold and still contain a joint that will leak under service. Solvent-welded joints can weep slowly, and a gauge with a wide scale may not move enough in ten minutes to notice. A fitting pushed home without solvent can sit tight against the pipe and only open when the ground moves or the line takes its working pressure.
General practice is to hold the test for a defined period and record the pressure at the start and at the end, with the gauge readable and in date. Confirm the hold time and the allowed drop against the project specification or the engineer. A test that is watched only at the start is a fill, not a test. Ask for the gauge serial number as well, so the same gauge can be checked against its calibration sticker next time the crew calls a test.
What does weak supervision miss on site?
Weak supervision misses the joint that was never made off properly. If nobody walks the trench while the line is under pressure, a damp patch at a fitting stays hidden until the pipe is buried. A slow weep at a thrust block may not show on the gauge at all in a short hold.
Ask the supervisor to log each joint as it is made, with the fitting type and the pipe length. Compare that log with the pipe and fittings delivered to site. Test records, delivery notes and the joint log together tell you whether the work was checked. Keep the joint log on site, not in an office across town, so a walk of the trench can be matched against it the same afternoon.
How do you check the test before backfill?
Hold the test before backfill and keep the trench open until the readings are written down. Ask for the gauge serial number, the start pressure, the end pressure, the time and the name of the person who watched it. Walk the line yourself while it is under pressure and look for damp ground, bubbles at fittings, and movement at thrust blocks.
If the contractor cannot produce the record, check what your contract says about testing and who holds the records. A line that was tested without a witness is only a claim.
What to do next
Ask the site supervisor for the last pressure test record on the current line. Read the start pressure, the end pressure, the hold time and the witness name. Then check the joint log against the pipe delivered.
Frequently asked questions
Who should witness a pipe pressure test in Berbera?
The role that signs the test record is set by the project specification or the engineer. General practice is that someone independent of the installation crew watches the gauge and walks the line while it is under pressure. Ask the project engineer which role that is on your contract.
What should a pressure test record show?
The gauge reading at the start, the reading at the end, the hold time, the date, and the name of the person who watched. Ask for the record before backfill.
Can a buried pipe still be tested later?
A buried line can be tested again, but a leak found after backfill costs more to expose and repair. Hold the test before backfill where the contract allows.
Local reporting: this article is written for building work in Berbera and Somaliland. Ground conditions, prices and rules differ between places; confirm the details for your own site.