3.5.5.2
Plastic Duct
Duct joints shall be made by brushing a plastic solvent cement on insides
of plastic coupling fittings and on outsides of duct ends. Each duct and
fitting shall then be slipped together with a quick one-quarter-turn twist
to set the joint tightly.
3.6
MANHOLES AND HANDHOLES
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NOTE: When preparing Section 16375A, ELECTRICAL
DISTRIBUTION SYSTEM, UNDERGROUND for a project
specification, the designer will edit the guide
specification as necessary to suit the specific
airfield or heliport installation. Note that
airfield type manholes, vaults, handholes, and their
associated frames and covers require a design for a
maximum single wheel load of 22,680 kg (50,000
pounds) or dual wheel load of 40,820 kg (90,000
pounds). Use steel conforming to ASTM A 36/A 36M,
for covers to airfield manholes, vaults, and
handholes. Use ductile iron for frames conforming
to ASTM A 536, grade 65-45-12.
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The manholes and handholes shall be as specified in Section 16375A
ELECTRICAL DISTRIBUTION SYSTEM, UNDERGROUND.
3.7
WELDING
The welding of supports and metallic ducts and welding or brazing of
electrical connections shall be formed by qualified welders.
3.8
CABLE MARKERS
Cable markers or tags shall be provided for each cable at duct entrances
entering or leaving manholes or handholes and at each termination within
the lighting vault. Cables in each manhole or handhole shall have not less
than two tags per cable, one near each duct entrance hole. Immediately
after cable installation, tags shall be permanently attached to cables and
wires so that they cannot be accidentally detached.
3.9
FRANGIBLE REQUIREMENTS
Frangible supports, couplings, and adapters shall be installed as indicated
or specified. At the 300 m 1000 foot cross bar and beyond, approach lights
shall be mounted up to 1.8 m 6 feet above concrete foundation on threaded
frangible couplings and 53 mm 2 inch electrical metallic tubing (EMT). For
mounting heights greater than 1.8 m 6 feet, approach lights shall be
mounted on low-impact resistant frangible towers as indicated.
3.10
ELEVATED AIRFIELD AND HELIPORT LIGHTS
Elevated lights shall be frangibly mounted, not to exceed 350 mm 14 inches
in height except where higher mounting is permitted in snow accumulation
areas. Equipment exceeding 350 mm 14 inches in height shall be frangibly
mounted as indicated.
SECTION 16526A
Page 36
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