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Accessories |
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| 8839 and 8840 Duct Smoke Detector Housings |
INTRODUCTION Air duct housings can be equipped with optional relays. These relays are utilized to operate any supplementary equipment when smoke or particles of combustion are detected. Note: Faraday control equipment guarantees only one device per zone when the detector operated relay function is critical. The connection of a remote lamp and a remote relay per detector is allowed with LifeWatch- 450 only, other conventional systems may use either a remote lamp or a relay. Air duct housings (see Ordering Information) are Underwriters Laboratories, Inc. listed.
DESCRIPTION Sensitivity of 8854 detectors can be checked by viewing the LED or an 8848 or 8844 multicolor remote lamp. 8710 and 8713 detectors can be checked from the panel or the L.E.D. A green flash indicates the detector has passed its self test. Amber indicates a trouble condition, and red indicates an alarm state. The detector unit employs a cross-sectional sampling principle of operation. Inlet sampling tubes are available in four lengths. Outlet sampling tubes are one common length. A continuous cross-sectional sample of air moving through the duct is taken. This averages the effects of laminar flow, stratification or skin effect phenomena occurring in the duct that could prevent combustion product or smoke (especially in large ducts) from reaching a spot type detector. In addition, the unique design of the Faraday sampling chamber insures uniform sensitivity in air velocities, ranging from a low of 300 feet per minute to as high as 4000 feet per minute. The inlet sampling tube length is determined by the width of the air duct being protected. The inlet tube nearest to but greater than the duct width should be used (see table). The inlet tube can then be trimmed at the job site to the exact width of the duct. The outlet sampling tube for all ducts, irrespective of width, has a fixed length of approximately 3 inches (7.5 cm) and is supplied with the duct housing. When the use of a remote relay is required, order model 8839 for conventional systems. Maintenance of the detector is easily accomplished by the removal of the duct housing sampling chamber cover. The detector, which plugs into the housing, is easily removed for cleaning by a trained technician. All that is necessary for the installation of the air duct detector is the cutting of three small holes for the sampling tube installation (template included) and the drilling of four holes for mounting the air duct housing. The unit is then easily mounted in place and connection made to the existing wires or terminals if optional accessories are utilized. See chart below for sampling tube selection table.
ENGINEER & ARCHITECT SPECIFICATIONS The air duct housing unit shall be designed for detection of combustion products and/or smoke in air conditioning and ventilation system ducts in compliance with NFPA Standard 90A. The assembly shall consist of a housing to accommodate sampling tubes which extend into and across the duct of the ventilation system. While the fans are operating, a continuous cross-sectional sampling of air from the duct shall flow through the photoelectric detector, after which the sampled air shall be returned to the duct. Air handling equipment shall be shut down by a signal from the fire detection system control equipment. When the air duct housing incorporates the optional relay, the shut down of air handling devices may be accomplished by a signal directly from the detector. The air duct housing shall be available with a self-contained power supply so that it can function as a stand-alone unit if desired. The self-contained stand-alone unit will power and supervise two satellite units. The air duct housing shall utilize a plug-in detector head located in the air sampling chamber. The detector shall be photoelectric. There shall be provisions to check the detector sensitivity in place under actual air flow conditions. The air duct housing shall be mounted directly outside of the air duct by means of four bolts (supplied). A template shall be provided for making necessary cutouts and holes. Complete instructions shall be supplied with the unit. The air duct housing shall be a Faraday Model (See listing on back page) and shall be Underwrit-ers Laboratories, Inc. Listed, specifically for use in air handling systems. Note to Architect: When building codes regulate the location of detectors within ventilating systems, make sure that the number and locations of detectors are in accordance with the code regulations. Operating Temperature:
Humidity:
Air Duct Velocity Range:
Sampling Tube Pressure Range of Differences:
Shipping Weight:
Caution:
Model 8839 only:
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