The goal of any fire suppression system is to detect fire as soon as it starts and immediately suppress it, preventing the fire from spreading. Heat and flames are detected, a trigger signals there is a fire, and the suppression system kicks into action suppressing the fire at the source. There are many types and sizes of fire suppression systems. The system design will vary based on the asset needing protection and the type of fire hazard. For example, a piece of ground support equipment at an airport would be treated differently than a server room.
Engineered vs. Pre-Engineered Systems
Two common types of fire suppression systems are engineered and pre-engineered systems. An engineered fire suppression system works by flooding an entire room with clean agent. Clean agents are gases that suppress fires without harming humans or equipment. A commercial or industrial facility with critical electronic systems that would be severely damaged by a sprinkler system using water is a perfect fit for a clean agent engineered system.
Unlike engineered systems, pre-engineered systems do not flood an entire room. Instead, they are designed to protect smaller enclosures or special hazards*. A few of the most common applications of pre-engineered systems include CNC/EDM machines, electrical panels, and engine compartments.
*There are a few exceptions where an engineered system is used to protect a local application. A fire suppression specialist will inform you if an engineered system could be a good use for your special hazard application.
Varieties of Chemical Agents Used
With a pre-engineered fire suppression system, a variety of chemical agents are used to suppress the fire. With Class A, B, and C fires, dry chemicals, clean agents, or carbon dioxide may be utilized. The same clean agents that are used in engineered systems can be used in pre-engineered systems, offering many of the same benefits. Class K fires require a wet chemical suppression system. The type of chemical agents used are highly dependent upon the class of fire, as well as the specific asset that needs protection.
Different types of fire suppression systems use different methods of fire detection. The two types of fire detection include active and passive detection systems. The active detection system needs an electrical power source to detect the fire by constantly monitoring for signs of heat or smoke. Active detection is very effective at sensing fires and automatically activating a fire suppression system. The drawback with active detection is that if power is lost, so is the system’s ability to detect fire.
Passive fire detection systems, like the Firetrace system, do not rely on electricity. Fire detection tubing is installed in and around the protected environment. When the detection tube comes into contact with the heat from a fire, the tube bursts. This triggers the suppression agent to discharge and suppress the fire.
Direct and Indirect Release Systems
An automatic fire suppression system can either be a direct or an indirect release system. With a direct release system, the suppression agent is dispersed through the burst hole in the fire detection tubing directly on the fire. With the indirect release system, the discharge of the suppression agent happens through the diffuser nozzles, which floods the area to suppress the fire quickly and thoroughly.
There are several distinct types of fire suppression systems, all of which have their own key features and benefits. It is fundamental in the system design stage to understand what is being protected and what are the potential fire hazards.
Photo provided by Kistler O’Brien Fire Protection