wrapped before it is placed in its final position shall have the wrapping
protected at sling points with roofing felt or other approved heavy
shielding material, or shall be handled with canvas slings. Damaged
wrapping shall be repaired as specified. Pipe in straight runs shall be
wrapped spirally, half-lapping the tape as it is applied. For pipe smaller
than 100 mm 4 inches, one layer half-lapped shall be used. For pipe 100 mm
4 inches and larger, two layers half-lapped shall be used with the second
layer wrapped opposite-hand to the first. Joints, coupling fittings, and
similar units and damaged areas of wrapping shall be wrapped spirally
beginning with one complete wrap 75 mm 3 inches back from each edge of the
corresponding size of straight pipe. On irregular surfaces such as valves
and other accessories, one layer half-lapped and stretched sufficiently to
conform to the surface shall be applied, followed by a second layer
half-lapped and applied with tension as it comes off the roll.
3.5.3.5
Coating Inspection and Testing
After field coating of the pipe joints, the entire pipe shall be inspected
with an electric holiday detector having an operating crest voltage of from
12,000 to 15,000 volts when using a full-ring, spring-type coil electrode.
The holiday detector shall be equipped with a bell, buzzer, or other
audible signal which operates when a holiday is detected. Detected
holidays in the protective covering shall be repaired. Occasional checks
of holiday detector potential will be made by the Contracting Officer to
determine suitability of the detector. The inspection for holidays shall
be performed just before covering the pipe with backfill and every
precaution shall be taken during backfill to prevent damage to the
protective covering. Equipment and labor necessary for inspection shall be
furnished by the Contractor.
3.5.4
Installing Buried Piping
Pipe and accessories shall be handled carefully to assure a sound,
undamaged condition. Care shall be taken not to damage coating when
lowering pipe into a trench and when backfilling. Nonmetallic pipe shall
be installed in accordance with pipe manufacturer's instructions.
Underground pipelines shall be laid with a minimum pitch of 25 mm/15 m 1
inch/50 feet. Horizontal sections shall have a minimum coverage of 450 mm
18 inches. Piping shall be free of traps and shall drain toward tank. The
full length of each section of underground pipe shall rest solidly on the
pipe bed. Piping connections to equipment shall be as indicated, or as
required, by the equipment manufacturer. Tank connections shall be made
with two elbow swing joints [or flexible connectors] to allow for
differential settlement. The interior of the pipe shall be thoroughly
cleaned of all foreign matter before being lowered into the trench and
shall be kept clean during installation. The pipe shall not be laid in
water or when the trench or weather conditions are unsuitable. When work
is not in progress, open ends of pipe and fittings shall be securely closed
so that water, earth, or other substances cannot enter the pipe or
fittings. Any pipe, fittings, or appurtenances found defective after
installation shall be replaced. Threaded joints shall be made with tapered
threads and shall be made perfectly tight with joint compound applied to
the male threads only. This requirement shall not apply for the gauging
hatch or similar connections directly over the tank where the line
terminates in a fitting within a cast-iron manhole designed to allow for
differential settling. Where steel piping is to be anchored, the pipe
shall be welded to the structural steel member of the anchor and the
abraded area shall be patched with protective coating or covering as
specified. Piping passing through concrete or masonry construction shall
SECTION 15555A
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