directions or hardened steel washer (disc) thrust bearings and rolling
radial bearings except that rolling thrust bearings and metallic journal
radial bearings shall be permitted for hollow metal doors when the
specified overpressure is less than 21 kPa 3 psi]. [Hinge Type 2 shall be
smooth operating and shall be provided with structural quality steel pins
and leafs, steel base washer (disc) thrust bearings, and metallic journal
radial bearings or other approved non rolling type bearings.] [Hinge Type
3 shall be provided with metallic bearings.]
2.2.2
Latching System
2.2.2.1
Latching Points
The number of latching points shall be determined by the door manufacturer.
[For multiple latching points, latching points can be provided at the
head, sill, and jambs.] [For jamb latching points, latching points shall
be provided at the jambs only.]
2.2.2.2
Latching System Operation
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NOTE: Retain the first sentence when hinge Type 1
is specified.
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Latching systems shall be capable of operating for the same number of
cycles specified for the door hinges where one latch operating cycle
consists of engaging and releasing using the handle. Latches shall remain
engaged until manually released and shall not release under blast loads or
rebound. [Manually operated latches shall remain in the released position
until manually engaged.] [Self-latching latches shall provide
self-activating engagement when the door is swung to the normal closed
position.] Handles shall release latches under a clockwise motion.
2.2.2.3
Latching Mechanism
[Latching mechanisms and latches for structural steel doors shall be
mounted on the seating face of the door.] [Latching mechanisms for hollow
metal doors shall be mounted on the seating face of the door and safety
covered.] [Unless otherwise approved, latch handle axles (spindles) for
[structural steel doors] [and] [reinforced concrete doors] shall extend
through the blast load carrying portion of the door and shall be provided
with suitable metallic journal bearings.] Latch handle axles shall be
manufactured of hardened steel or stainless steel, and axles requiring
lubrication shall be provided with easily accessible lubrication fittings.
2.2.2.4
Safety Cover
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NOTE: Safety covers apply to structural steel and
hollow metal doors.
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Safety covers shall consist of steel housings that enclose the latching
mechanism such that only the operating rods are exposed.
2.2.2.5
Cover Plate
Cover plates for structural steel doors shall be manufactured of minimum 6
SECTION 08390
Page 18
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