The Kidde-Fenwal DETECT-A-FIRE units are the “heart” of many Fire Protection Systems. These highly reliable devices have a been a standard of the industry for 65 years, with thousands of detectors in use controlling the release of extinguishants such as clean agents, CO2, water, or dry chemicals. In some systems the device is used as an ALARM device, to sense overheat or fire, and alert personnel. In select systems, the device is used as an ALARM device, to sense overheat or fire and alert personnel. DETECT-A-FIRE detectors have met with wide acceptance because they are designed with RATE COMPENSATION. This provides a unique advantage over both fixed temperature and rate-of-rise types of detectors because only the DETECT-A-FIRE detector accurately senses the surrounding air temperature regardless of the fire growth rate. At precisely the predetermined danger point, the system is activated. Fixed temperature detectors must be completely heated to alarm temperature and therefore a lag in response time may occur with a fast rate fire. Rate-of-rise devices, on the other hand, are triggered by the rate of increase in ambient temperature and are subject to false alarms caused by harmless, transient thermal gradients such as the rush of warm air from process ovens.