3.13
CATHODIC PROTECTION
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NOTE: Cathodic protection is mandatory for
underground metallic gas distribution lines. The
type and design of cathodic protection will be in
accordance with TM 5-811-7. Stations will be
provided for testing the cathodic protection system.
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Cathodic protection shall be provided for all metallic gas piping installed
underground and shall be installed as specified in [Section 13110ACATHODIC
PROTECTION SYSTEM (SACRIFICIAL ANODE)] [Section 13112A CATHODIC PROTECTION
SYSTEM (IMPRESSED CURRENT)].
3.14
TESTS
3.14.1
Destructive Tests of Plastic Pipe Joints
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NOTE: Destructive tests of plastic pipe joints are
provided as a designer option. Destructive tests
are considered useful in assuring that good joints
will be made. Delete the paragraph if this option
is not exercised.
**************************************************************************
Each day, prior to making polyethylene heat fusion joints or fiberglass
adhesive joints, a joint of each size and type to be installed that day
shall be made by each person performing joining of plastic pipe that day
and destructively tested. At least 3 longitudinal straps shall be cut from
each joint. Each strap shall be visually examined, shall not contain voids
or discontinuities on the cut surfaces of the joint area, and shall be
deformed by bending, torque, or impact, and if failure occurs, it must not
initiate in the joint area. If a joint fails the visual or deformation
test, the qualified joiner who made that joint shall not make further field
joints in plastic pipe on this job until that person has been retrained and
requalified. The results of the destructive tests shall be recorded to
include the date and time of the tests, size and type of the joints,
ambient conditions, fusion iron temperature and names of inspectors and
joiners.
3.14.2
Pressure and Leak Tests
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NOTE: Specify correct test pressure (including
Class Location) to be used for tests of gas line
systems in accordance with ASME B31.8. Test
pressures should recognize the weakest component of
each system tested for the design pressure, the
maximum allowable operating pressure, and the gas
supplier's maximum operating pressure.
The test pressure will be 150 percent of the maximum
operating pressure or 350 kPa (50 psig), whichever
is greater. However, the maximum test pressure must
not be more than three times the design pressure of
the pipe.
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SECTION 02556A
Page 26
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