of plastic resin shall be 0.91 mm 36 mils for pipe sizes 150 mm 6
inches and larger, and 0.58 mm 23 mils for pipe sizes under 150 mm
6 inches.
b.
Fittings and Other Surfaces: Fittings, couplings, regular
surfaces, damaged areas of extruded polyethylene coating and
existing piping affected by the Contractor's operations shall be
protected by the application of tape. Surfaces to be tape wrapped
shall be clean, dry and grease free. Tape conforming to FS
L-T-1512 and of the type specified below shall be applied over a
primer compatible with the tape and the extruded polyethylene
coating.
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NOTE: Polyethylene heat shrink sleeves can be used
for welded joints and pipe with factory applied
polyethylene coating in lieu of protective tape;
however not recommended for systems with numerous
bends.
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(1) Fittings, Couplings, and Regular Surfaces: Tape shall be
initially stretched sufficiently to conform to the surface to
which it is applied, using one layer lapped at least 25 mm one
inch.
Tape shall overlap the extruded polyethylene coated piping 80
mm
3 inches at all joints. A second layer, lapped at least 25 mm
one
inch, with a tension as it comes off the roll shall be applied
and
pressed to conform to the shape of the component. Tape shall
conform to FS L-T-1512, Type II, 0.51 mm 20 mils nominal
thickness. Do not wrap joints until completion of pressure
testing.
(2) Damaged Areas of Extruded Polyethylene Coating: Residual
material from coating shall be pressed into the break or trimmed
off. Tape shall be applied spirally and one-half lapped as it is
applied. Tape shall extend 80 mm 3 inches beyond the damaged
area. A double wrap of one full width of tape shall be applied at
right angles to the pipe axis in a manner to seal each end of the
spiral wrapping. Tape shall conform to FS L-T-1512, Type II, 0.51
mm 20 mils nominal thickness.
(3) Existing Piping Affected by the Contractor's Operation:
Wrap
to 80 mm 3 inches beyond the point of connection.
c.
Flanges, Valves, and Irregular Surfaces: These items shall
receive coal tar base coating conforming to MIL-C-18480 applied to
a minimum dry film thickness of 0.76 mm 30 mils.
2.1.10.2
Cathodic Protection
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NOTE: Cathodic protection is required for all parts
of an underground storage tank system that are made
of steel (except for FRP coated steel tanks) and
that are in contact with the ground. Cathodic
protection shall be designed by a licensed corrosion
engineer or cathodic/corrosion protection specialist
certified by the National Association of Corrosion
Engineers (NACE) in accordance with the current
SECTION 15192N
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