"The Fenwal Detect-A-Fire Fire Detectors are the ""heart"" of many fire protection systems. These highly reliable devices have been a standard of the industry for over 45 years. Many thousands of these units are now in use controlling the release of extinguishants such as clean agents, CO2, water, or dry chemicals. In some systems the Detect-A-Fire is used as a fire alarm device, to sense overheat or fire and alert personnel. In other systems it is used as a release device, to sense fire and actuate fire attack systems. The Fenwal Detect-A-Fire has met with wide acceptance because it is designed with ""rate compensation."" Rate compensation provides a unique advantage over both fixed temperature and rate-of-rise types of detectors because only the Detect-A-Fire unit accurately senses the surrounding air temperature regardless of the fire growth rate. At precisely the predetermined danger point, the system is activated.
The secret of the unit's sensitivity is in the design. The outer shell is made of a rapidly expanding alloy which closely follows changes in surrounding air temperature. The inner struts are made of a lower expanding alloy. Designed to resist thermal energy absorption and sealed inside the shell, the struts follow temperature changes more slowly. A slow rate fire will heat the shell and struts together. At the ""set point,"" the unit will trigger. A transient rush of warm air up to 40F/min. may expand the shell, but not enough to trigger the unit, virtually eliminating false alarms. If a fast rate fire starts, the shell will expand rapidly. The struts will close and the unit will trigger. The faster the fire rate of growth, the sooner the Detect-A-Fire will react. Fenwal Detect-A-Fire units are not position sensitive. Horizontal and vertical detectors refer to the most common mounting configuration for that unit. Each type can be mounted either horizontally or vertically depending on the application and installation requirements