disturb the magnetic field shall cause a tamper alarm. [Ball
bearing door trips shall be mounted within vault door headers such
that when the locking mechanism is secured, the door bolt engages
an actuator, mechanically closing the switch. Door bolt locking
mechanism shall be completely engaged before the ball bearing door
trip is activated. Provide circuit jumpers from the door.]
(2)
Glass breakage detection
(a) Breakwire sensors: Sensors shall consist of fine wire
embedded in or affixed to interior of glazing. Breakage of
protected glazing shall result in wire breakage. Wire shall be
hard-drawn copper and not exceed 26 AWG diameter. If affixed to
glazing, protect sensor wire by a clear coating which shall not
inhibit sensor functioning. Sensor shall be terminated in
insulated connectors which are [concealed] [tamper protected].
(b) Glass breakage sensors: Sensors shall detect window breakage
by responding to sonic or vibration frequencies that accompany
breaking glass. Sensors shall selectively filter input to
minimize false alarms. Sensors shall be contained in a
fire-resistant ABS plastic housing and shall be mounted in contact
with the window. Glass breakage sensors shall initiate alarm when
glass they protect is cracked or broken. Sensing shall be
accomplished through the use of a mechanical filtered
piezoelectric element. Sensor shall have a sensitivity adjustment
controlling output voltage from the piezoelectric element which
triggers a solid-state latching device. Provide sensor with an
LED for adjusting sensitivity. Supply sensor with a two-sided
polyurethane tape with acrylic adhesive. Provide sensor with an
exterior label to protect tape from direct sunlight. Sensor shall
not initiate alarm in response to seismic vibrations or other
ambient stimuli. [Test glass breakage sensors by using test units
supplied by the manufacturer which simulate glass breakage.]
(c) Screening: Construct security screens from a maximum of 26
AWG insulated hard-drawn copper. Connect screens to an alarm
circuitry by means of flexible armored cords. Security screen
circuitry shall provide end-of-line resistors in series or
equivalent methods ensuring alarm activation if short-circuiting
of the screen is attempted. [If screen corners are not installed
as a breakwire sensor (wire traps), provide tamper switches.
Provide tamper switches in the frames as required with not less
than one switch on each side if dimensions are 610 mm 2 feet
square or less, and two switches if dimensions exceed 610 mm 2
feet square. Tamper switches shall be corrosion-resistant,
spring-operated, and shall initiate an alarm with a movement of 50
mm 2 inches or less before access to the switch is possible.
Electrical characteristics of the switch shall match the alarm
system requirements.]
b.
Object Protection
(1) Capacitance proximity sensor: Sensor shall consist of two
solid-state synchronous oscillators, a reference oscillator, and a
detecting oscillator. Detecting oscillator shall be electrically
connected to the sensing wire (antenna) circuitry, such that
capacitance of antenna circuitry determines frequency and phase of
oscillation. If an intruder approaches protected objects,
SECTION 13703N
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