18Apr 2019
by Nick Potter

Kidde Fenwal Detect-A-Fire Series 27100 & 28000 Vertical Thermal Detectors Available!

The Kidde Fenwal DETECT-A-FIRE thermal detectors are the heart of many fire protection systems…and has been for over 65 years as the first Rate-Compensated detector on the market.

From gas stations to paint spray booths, from range hoods to large power generation systems, from engine compartments to schools, factories and offices, the D-A-F detector is on guard, controlling the release of extinguishants such as clean agents, CO2, water or dry chemicals.

Kidde Fenwal Thermal Heat Detector

They also can be used as an ALARM device to sense overheat or fire and alert personnel. Rate compensation provides a unique advantage of activation at a pre-determined danger point, whether it be a slow fire or a fast fire.

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 pre-determined 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.

The key to 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 slower 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, actuating the alarm or releasing the extinguishant.

A transient rush of warm air up to 40°F/min. may expand the shell, but not enough to trigger the unit. By ignoring transient warm air excursions, the DETECT-A-FIRE detector virtually eliminates false alarms prevalent with rate-of-rise devices.

If a fast rate fire starts, the shell will expand rapidly. The struts will close, actuating the alarm and/or releasing the agent. The faster the fire rate of growth, the sooner the DETECT-A-FIRE detector will react.

If you have a requirement for the Kidde Fenwal Detect-A-Fire Series 27100 & 28000 Vertical Thermal Detectors please contact us NOW on the ‘Contact US’ link above so that we can provide pricing.