that shows when the unit is in alarm condition. Detectors shall not be
adversely affected by vibration or pressure. Detectors shall be the
plug-in type in which the detector base contains terminals for making
wiring connections. Detectors that are to be installed in concealed (above
false ceilings, etc.) locations shall be provided with a remote indicator
LED/LCD suitable for mounting in a finished, visible location.
2.5.2.1
Ionization Detectors
Ionization detectors with a dual chamber shall be responsive to both
invisible and visible particles of combustion. One chamber shall be a
reference chamber and the second a sampling chamber. Detectors containing
radium shall not be provided. Detectors shall not cause an alarm condition
due to anticipated fluctuations in relative humidity. The sensitivity of
the detector shall be field adjustable to compensate for operating
conditions. Detector shall require no replacement or readjustment to
restore it to normal operation after an alarm condition. Each detector
shall be capable of withstanding ambient air velocity up to [1.5] [_____]
meters/second [300] [_____] fpm in accordance with UL 268. Addressable
smoke detectors shall be capable of having the sensitivity being remotely
adjusted by the control panel.
2.5.2.2
Photoelectric Detectors
Detectors shall operate on a light scattering concept using an LED light
source. Failure of the LED shall not cause an alarm condition. Detectors
shall be factory set for sensitivity and shall require no field adjustments
of any kind. Detectors shall have an obscuration rating in accordance with
UL 268. Addressable smoke detectors shall be capable of having the
sensitivity being remotely adjusted by the control panel.
2.5.2.3
Projected Beam Smoke Detectors
Detectors shall be designed for detection of abnormal smoke densities.
Detectors shall consist of separate transmitter and receiver units. The
transmitter unit shall emit an infrared beam to the receiver unit. When
the signal at the receiver falls below a preset sensitivity, the detector
shall initiate an alarm. The receiver shall contain an LED which is
powered upon an alarm condition. Long-term changes to the received signal
caused by environmental variations shall be automatically compensated.
Detectors shall incorporate features to assure that they are operational; a
trouble signal shall be initiated if the beam is obstructed, the limits of
the compensation circuit are reached, or the housing cover is removed.
Detectors shall have multiple sensitivity settings in order to meet UL
listings for the different distances covered by the beam. In the event of
beam interference for more than three seconds a trouble alarm shall be
transmitted.
2.5.2.4
Duct Detectors
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NOTE: The requirements for Duct Detectors will be
coordinated with the HVAC requirements and Section
15951 DIRECT DIGITAL CONTROL FOR HVAC AND OTHER
LOCAL BUILDING SYSTEMS. All required duct detectors
will be shown on the contract drawings.
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Duct-mounted photoelectric smoke detectors shall be furnished and installed
SECTION 13851A
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