less than 10 dynes/sq. cm 0.000145 psi
impinging on speaker mcrophone or handset
Amplifier Protection:
Prevents damage from shorted or open output
Power Output:
[______] watts or greater.
2.3.3.4
Power Line Surge Protection
All amplifiers shall have a device, whether internal or external, which
provides protection against voltage spikes and current surges originating
from commercial power sources per IEEE C62.41 B3, combination wave form and
NFPA 70. Fuses shall not be used for surge protection. The surge
protector shall be rated for a maximum let thru voltage of 350 Volts ac
(line to neutral) adn 350 Volts ac (neutral to ground). Surge protection
device shall be UL listed and labeled as having been tested in accordance
with UL 1449.
2.3.3.5
Signal Surge Protection
All amplifiers shall have internal protection circuits which protects the
component from mismatched loads, direct current and shorted output lines.
Communication cables/conductors shall have surge protection installed at
each point where it exits or enters a building.
2.3.4
Horn-Type Loudspeakers
Horn-type loudspeakers shall be all metal [weather proof] construction
complete with universal mounting brackets. [Shall be suitable for Class
[1, Groups C and D] [1, Groups B,C, and D] [2, Groups E, F and G] hazardous
locations and equiped with 13 mm 1/2 inch threaded conduit entry]. The
horn type loudspeakers shall be provided with an internally mounted,
factory installed line transformers. and shall as a minimum conform to the
following specifications:
Power Rating:
25 [_____] watts
Horizontal Dispersion
Angle:
[57] [70] [90] [115] [_____]
Verticle Dispersion
Angle:
[57] [90] [115] [_____]
Axial Sensitivity:
Minimum of [60] [_____] dB
Line Transformers
Power Rating:
At least 4 watts with at least four taps and
comply to EIA-160 with insertion rate
of 0.5 dB.
2.3.5
Cone-Type Loud speakers
Cone-type loud speakers shall be enclosed in a [steel housing] [back boxes]
and shall be acoustically dampened with a front face of at least 1.21 mm
0.0478 inches steel. The whole assembly shall be rust proofed and factory
primed complete with mounting assembly and suitable for for [surface
ceiling] [flush ceiling] [pendant] [wall] mounting with a relief of back
pressure. The cone-type loadspeakers shall comply with the following
SECTION 16721
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