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HYDROSTATIC TESTING - PIPELINES
We test a wide variety of pipelines. Some are new lines tested before production and therefore
tested to higher test pressures and some lines are already in service and thus are subject to
testing limitations, such as production valves and other fittings. Some lines are above ground,
some below ground, some over water, and some under water.
We often test oil, diesel fuel, and
methanol lines at fuel docks in various places along the Gulf Coast. We also test liquid mud
lines and completion fluid lines at "mud" docks in AL, MS, LA, and TX.
Pipeline test pressures
are regulated by the Code of Federal Regulations. Generally the test pressures must be one and one
half times the maximum allowable working pressure. The maximum allowable working pressure is
the maximum pressure that any source in the pipeline system can exert if all pressure
outlets are suddenly closed. For example, if the pressure source is a pump whose maximum pressure
is 80 PSI and we add an inertia factor of 10 PSI caused by the sudden closure of valves, the
maximum allowable working pressure would be 90 PSI. The minimum test pressure would be one and
one half times 90 PSI, or 135 PSI. Of course a pipeline can be tested to higher pressures provided
all components in the system are rated for such test pressures. Test pressures are held for
varying lengths of time depending on the customer's wish. Generally, in order to record pressures
and time accurately, a chart recorder is used to make a printout which shows the pressure on the
line and the length of time the line has pressure on it. Also, a dead weight indicator, either
manual or digital, which gives a very accurate reading of actual pressures on the line, is
used and the pressures are recorded at pre-determined intervals during the test process. Drops in
pressure may indicate a leak in the system or may be caused by ambient temperature fluctuations.
Increases in pressure may be the result of a rise in ambient temperature.
After we test a line
and it passes the test, metal tags bearing a serial number, the maximum allowable working pressure,
and the test date are affixed to each termination point in that particular test. For example, if
the pipeline tested is a test between two valves, we would affix a tag with the same serial number
to each terminating point (valve) of the test. If the pipeline branches to more termination points,
more tags bearing the same serial number would be affixed.
Some customers also like to have the
test information paint stenciled on the pipe itself, perhaps in several places.
After testing
and tagging the pipelines, test documents are issued which record all the tests done at the facility
identifying the tests by the serialized tags on the pipeline. The test documents are signed by the
technician and only the copy kept for the regulatory agency has our Company seal applied over the
technician's signature. This assures the regulatory agency that the test document is not a copy.
Click Here for information about Hydrostatic Transfer Hose Testing
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