Repeat the above steps until the 5-mile section of pipeline has be
tested and all leaks repaired.
Pressurize the whole 5-mile section for a 24-hour test if there is
enough time.
Anchor the end of the pipeline after the test is over or hold it down
with heavy equipment so that it cannot whip around. Warn everyone in
the area to stand clear of the line. Then empty the air from the line
by opening the gate valve at the end of the test section. Open the
gate valve as quickly as possible.
Preparations for Testing.
Before the test begins several actions
should be taken.
To ensure that the test runs smoothly, personnel
should:
Test all radios and telephones.
Check the accuracy of all gages.
Make sure enough repair clamps are on hand.
Move in fire fighting equipment.
Make sure a tank vehicle and drums are nearby in case a section of
line has to be drained.
See that shovels and material to dig and line a pipe are at the test
site in case there is a spill.
The pipeline should be divided into test sections. The usual test
length is the distance between pump stations (about 15 miles). Shorter
distances can be tested by using gate valves to divide the pipeline into
smaller segments.
During testing, line pressure in welded pipelines is measured by gages
at pump stations and at line taps between pump stations. Before the test
begins, over coupling leak clamps with pressure gages are mounted on
coupled pipelines to measure line pressure. The clamps are mounted every
one third mile, if practical. If not, they are used at least every mile.
To mount an over coupling leak clamp for a pressure test, personnel
should:
Remove the vent plug and put a pressure gage in the vent plug hole.
Loosen the split ring coupling on the pipeline.
Remove the gasket or push a nail under the gasket to make a small
leak. (The nail should not damage the gasket and should not get in
the way of the over-coupling leak clamp.)
Remove nuts and bolts from the over coupling leak clamp.
Fit the two halves of the leak clamp and the two part gaskets over and
around the split ring coupling.
Put the large side bolts back in on each side of the clamp and tighten
them.
Tighten smaller packing bolts around the housing on the leak clamp to
form seal between the gaskets and the pipe.
PART C - PIPELINE PATROLLING
When put into service, pipelines are patrolled by at least two people.
The patrols look for leaks and signs of a leak such as an oil slick on a
stream and/or dead or wilted plant life nearby. They report all leaks on
12-109
QM 5099
Previous Page
