threshold may not be required for installation
operating below 125 kVp if the primary beam does not
strike the door area).
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Thresholds are specified in Section 08710 DOOR HARDWARE. Line thresholds
with a single sheet of lead to provide required shielding.
2.10
LEAD WINDOW FRAMES
Lead window frames for viewing windows mounted in lead-lined doors shall be
constructed from [lead extrusion welded in one piece] [extruded aluminum
alloy with concealed lead lining], splayed on four sides for wide-angle
viewing. Frames shall form a minimum overlap of 9 mm 3/8 inch at the
perimeter of the lead glass or twice the thickness of the shielding,
whichever is greater. Thickness of lead shall be the same as the lead in
the barrier in which they occur. Frames can be either solid or telescoping
type. Lead stops shall be provided for glass or acrylic installation.
Clear acrylic panel shall be provided with lead equivalence [_____] [as
required by unit in which panel is installed.] [ Provide a baffled slot
for voice passage in the frame.]
2.11
LEAD LIGHTPROOF LOUVERS
Lead lightproof louvers for doors shall be fabricated entirely of lead of
not less than the thickness of lead in barrier in which they are installed.
Louvers shall be one-unit construction designed with a maze-type blade to
exclude the passage of light. Louvers shall allow 30 percent free area for
air circulation. Louvers shall be factory-fitted, boxed separately, and
shipped with door or assembled before shipment.
2.12
LEAD-LINED STEEL DOORS AND FRAMES
2.12.1
Doors
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NOTE: Threshold construction is determined by
radiographic equipment required, work load, and
location of radiation source from the door (i.e.,
threshold may not be required for installation
operating below 125 kVp if the primary beam does not
strike the door area).
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Doors shall conform to Section 08110 STEEL DOORS AND FRAMES, in accordance
with SDI A250.8, Grade II, heavy duty, Model 1, minimum 18 gage faces with
steel stiffeners throughout. Apply unpierced lead sheet, of thickness
equal to that used in the adjoining wall, in the center of the door between
the two faces, continuously from top to bottom and edge to edge. Shield
cutouts for locksets with sheet lead of the same thickness as used in the
door; lap lead lining of locksets and the door lining. Prepare doors to
receive viewing windows and louvers as indicated. Provide removable stops
for glazed openings. Use Section 08710 DOOR HARDWARE for protective
hardware requirements. Line thresholds with a single sheet of lead to
provide required shielding.
2.12.2
Frames
Steel frames shall be as specified in Section 08110 STEEL DOORS AND FRAMES.
SECTION 13090
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