80 percent of the switch capacity. Switches shall be rated for a minimum
lifetime of 1,000,000 operations. The magnet assembly shall house the
actuating magnet.
2.6.1.2
Housing
The housings of surface mounted switches and magnets shall be made of
nonferrous metal and shall be weatherproof. The housings of recess mounted
switches and magnets shall be made of nonferrous metal or plastic.
2.6.1.3
Remote Test
A remote test capability shall be provided. The remote test shall be
initiated when commanded by the alarm annunciation system. The remote test
shall activate the sensor's switch mechanism causing an alarm signal to be
transmitted to the alarm annunciation system. The remote test shall
simulate the movement of the actuating magnet relative to the switch
subassembly.
2.6.2
Glass Break Sensor, Piezoelectric
The glass break sensor shall detect high frequency vibrations generated by
the breaking of glass while ignoring all other mechanical vibrations. An
alarm signal shall be transmitted to the alarm annunciation system upon
detecting such frequencies.
2.6.2.1
Sensor Element, Piezoelectric
The sensor element shall consist of piezoelectric crystals. The sensor
element housing shall be designed to be mounted directly to the glass
surface being protected. Only the adhesive recommended by the manufacturer
of the sensor shall be used to mount detectors to glass. The detection
pattern of a sensor element shall be circular with at least a 3 meter 10
foot radius on a continuous pane of glass. A factory installed hookup
cable of not less than 1.8 m 6 feet shall be included with each sensor.
The sensor element shall not exceed 1024 square mm 1.6 square inches. The
sensor element shall be equipped with a light emitting diode (LED)
activation indicator. The activation indicator shall light when the sensor
responds to the high frequencies associated with breaking glass. The LED
shall be held on until it is turned off manually at the sensor signal
processor or by command from the alarm annunciation system.
2.6.2.2
Sensor Signal Processor, Piezoelectric
The sensor signal processor shall process the signals from the sensor
element and provide the alarm signal to the alarm annunciation system. The
sensitivity of the sensor shall be adjustable by controls within the sensor
signal processor. The controls shall not be accessible when the sensor
signal processor housing is in place. The sensor signal processor may be
integral with the sensor or may be a separate assembly. Piezoelectric
technology shall power the sensor. The piezoelectric crystal shall
generate its own electricity when it bends as the glass breaks. Bending of
the transducer must occur for the sensor to go into alarm, thus providing
false alarm immunity.
2.6.2.3
Glass Break Simulator, Piezoelectric
The Contractor shall provide a device that can induce frequencies into the
protected pane of glass that will simulate breaking glass to the sensor
SECTION 13720A
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