or repair. The remainder of the edge may be in one piece up to a
maximum of 6000 mm 20 feet.
c.
Bumper(s): Each door leaf edge provided with a safety edge shall
be protected by a spring type bumper(s). Bumper shall be designed
to absorb 150 percent of the door drive force when door is pushed
in an emergency. For continuous safety edges, bumpers shall
extend to the sides. For sectional safety edges, the bumper can
interrupt the safety edge for a distance not greater than 305 mm
12 inches.
d.
Keyed bypass: Provide a keyed bypass to the door controls to
render the safety edges in a temporary "repair" mode, if
necessary. The door drive shall be restored from its "fail safe"
mode by activation of the keyed bypass.
2.3.6.1
Electrical Safety Edges
Connect the safety edge in series with the necessary relays and resistors
to make the system complete. The service shall be not more than 24 volts
and the circuit shall be normally energized so that the malfunction of any
of the component parts will make the door inoperative. Wire sensing edges
to provide for control reliable 4-wire operation of hangar door so that any
power loss to the sensing edges is experienced, then the door becomes
inoperable until power is restored and a reset operation is initiated.
Install sensing edges to operate through a normally energized relay so that
when the sensing edge is compressed the relay contacts open. Install relay
contacts to also open if any component in the sensing edge control circuit
is broken so as to break continuity. Use 100 volts electrical service to
the control circuit. Ensure service to the sensing edge does not exceed a
nominal 24 volts. Install a large red indicator light and/or a loud siren,
to be simultaneously activated with the actuation of any sensing edge, to
indicate the presence of an obstruction.
2.3.7
Warning Device
Provide a clearly audible signal on each [individually operated leaf]
[group of leaves]. The warning device shall:
a.
Operate when the push button is actuated for movement of the door
in either direction;
b.
Sound 5 seconds before the door moves, and while the door is
moving; and
c.
Consist of not less than a 150 mm 6 inch diameter bell or
equivalent decibel-rated horn, loud enough to be heard in the
hangar and on the apron.
2.3.8
Emergency Operation
Hangar doors[, including tail doors,] shall be constructed and equipped so
that they can be operated-manually or by tractors from the hangar floor in
case of power failure. Manual operation of hangar doors shall be designed
to avoid damage to safety edges.
2.3.9
Electrical Work
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SECTION 08342
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