surface. Remove paint or other coverings on mating surfaces of special
boxes such as for fire alarm systems, buzzers, and signal lights, including
areas between box and cover, box and wall, and box and conduit. Remove
insulating material to maintain a low-resistance ground system and to
ensure firm mating of metal surfaces.
3.1.4
Floor Panel Setting
Place a polyethylene film of 6-mil thickness over the structural floor of
the parent room before any other work is set thereon. Provide a 3 mm 1/8
inch thick layer of hardboard over this film with joints loosely butted.
Over this layer provide an additional layer of similar filler material of
equal thickness as the projection of the framing-joining member from the
bottom surface of the floor panel leaving no more than 6 mm 1/4 inch space
between the hardboard and the framing-joining member.
3.2
FRAMING-JOINING SYSTEM
Tighten screws with a calibrated adjustable torque wrench so that equal
torque can be set on each screw. (Proper torque values will be
approximately 9 Nm 80 inch pounds, but may vary somewhat depending on the
manufacturer).
3.3
DOOR ASSEMBLIES
Mount so that the clearance between the door edges and frame shall not vary
more than 2 mm 1/16 inch and the innerface of the door periphery does not
vary more than 2 mm 1/16 inch from the plane of the face of the stop.
Through-bolt hinges to the door and the frame.
3.4
LINE FILTERS
Provide filters for incoming electrical power lines [, including neutrals,]
and for incoming telephone and signal lines. Support filters independently
of the shielding.
3.5
WAVEGUIDE-TYPE AIR VENTS
[Provide each inlet and return air duct with the number and size of
waveguide-type air vents at each location where the ducts enter the
shielded enclosure.] [As a minimum, provide each enclosure with one 300 mm
12 inch square and one 300 mm 12 inch square return waveguide-type air
vent.]
3.6
EXHAUST FAN
Mount on [wall] [or] [ceiling] over the exhaust vent on the exterior
surface of shielded enclosure. Provide power from electrical source
exterior to the shielded enclosure.
3.7
CONDUCTOR INSTALLATION
Provide filtered conductors in conduit, except for coaxial cables, from
filter to shielding and penetrate the enclosure through threaded rigid
steel conduits. [Twist conductors leading from the filters and conductors
inside the shielded enclosure approximately 10 turns per foot in the
conduit.]
SECTION 13093N
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