boiler exhausts shall be constructed as shown in the drawings and shall be
configured as a WBC or WBC array. The circumferential penetration welds
are primary shield welds and shall be inspected and tested as indicated.
2.8.3
Waveguide Penetrations
Waveguide penetrations for dielectric fibers or hoses shall be implemented
in the same manner as piping penetrations. Dielectric hoses or pipes shall
be converted to metal waveguide piping before penetrating the shield.
Conductors, such as wires and fiber cable strength members, shall not pass
through the waveguide opening.
2.9
GROUNDING STUD
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NOTE: Grounding stud will be provided only for
small (under 100 square meters (1,000 square feet)
of floor area) bolted and welded enclosures.
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Enclosure shall have 13 mm 1/2 inch diameter stud circumferentially welded
to each side of the shielding penetration plate.
2.10
PENETRATION PLATES
Penetration plates shall be minimum 6 mm 1/4 inch thick and sized as shown
on the drawings. The penetration plate shall overlap the shield
penetration cutout dimension by a minimum of 150 mm 6 in on each side. The
penetration plate shall be [welded] [bolted] to the HEMP shield [with
continuous circumferential EM welds.] [with bolts 75 mm 3 in on center.]
2.11
GALVANIZING
Galvanizing, when practical and not otherwise indicated, shall be
hot-dipped processed after fabrication. Galvanizing shall be in accordance
with ASTM A 123/A 123M, or ASTM A 653/A 653M, as applicable. Exposed
fastenings shall be galvanically compatible material. Electrolytic couples
and dissimilar metals that tend to seize or gall shall be avoided.
2.12
EM SHIELDED CABINETS AND PULL BOXES
Cabinets and pull boxes shall be modified NEMA [1] [_____] in accordance
with NEMA ICS 6 made of corrosion resistant steel of not less than 1.9837
mm 14 gauge thick with welded seams and galvanized bulkhead cover plates.
Access cover plates shall be hinged with EM gaskets and 75 mm 3 inch
maximum bolt spacing. Design shall include thick cover plates, folded
enclosure edges, and bolt spacers to prevent uneven gasket compression and
enclosure deformation. Gasket shall be easy to replace. Gasket contact
areas shall be tin-plated using the electrodeposited type I method in
accordance with ASTM B 545. Conduit hub shall be circumferentially EM
welded to the enclosure. The cabinets shall be finished with a
corrosion-inhibiting primer and two coats of baked or finish enamel.
Cabinets shall be provided with mounting brackets for wall mounting or legs
for floor mounting. Cabinets and boxes of each type shall be factory
tested in accordance with IEEE Std 299 and Table I of this specification.
2.13
QUALITATIVE MONITORING SYSTEM
A built-in shield monitoring system for SELDS testing shall be provided.
SECTION 13095A
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