Hawco 312-300 12quot 14 NPT Female Hexagonal Retaining Nut for Detect-A-Fire Heat Detectors Pack of 6
Pleasenote This product incurs additional shipping charges.Hawco 312-300 12 14 NPT Female Hexagonal RetainingNut for Detect-A-Fire Heat Detectors Pack of 6DETECT-A-FIRE D-A-F detectors are the heartof many fire protection systems. The highly reliable D-A-F has been thestandard for over 75 years. The D-A-F is used for signaling overheat or fireconditions. In most applications the D-A-F provides the initial heat sensingthat is used to activate suppression systems using clean agent CO2 inertgases wet or dry chemicals or water.D-A-F detectors are widely accepted because they aredesigned with rate compensation. This provides a unique advantage over bothfixed temperature and rate-of-rise types of detectors because the D-A-Fdetector accurately senses the surrounding air temperature regardless of thefire growth rate. At the pre-determined set point the system is activated.Fixed temperature detectors must be completely heated to alarm temperature andtherefore a lag in response time may occur with a fast rate fire. Rate-of-risedevices on the other hand are triggered by the rate of increase in ambienttemperature and are subject to false alarms caused by harmless transientthermal gradients such as the rush of warm air from process ovens. The key to the detectors sensitivity is in the design. Theouter shell is made of a rapidly expanding alloy which closely follows changesin surrounding air temperature. The inner struts are made of a slower expandingalloy. Designed to resist thermal energy absorption and sealed inside theshell the struts follow temperature changes more slowly. A slow rate fire willheat the shell and struts together. At the set point the detectorwill trigger actuating the alarm or releasing the extinguishant.A transient rush of warm air up to 40Fmin. mayexpand the shell while not triggering the detector. By ignoring transient warmair excursions the D-A-F detector virtually eliminates false alarms prevalentwith rate-of-rise devices. If a fast rate fire starts the shell will expandrapidly. The struts will close actuating the alarm andor releasing the agent.The faster the fire rate of growth the sooner the D-A-F detector will react.