Fire detection methods smoke detectors

There are a number of ways by which fire can be detected. The three principal fire detection methods involve sensing the heat, either as actual temperature or as rate-of-rise of temperature, the presence of flame or the presence of smoke. There is one other detection method which identifies a pre-fire condition and that is a flammable gas detector whose use is limited to places where flammable gases are likely to be present. 

Sprinkler systems are an effective way to contain fires. The system consists of an array of sprinkler heads connected to a water supply. The heads are mounted in a high location (usually near ceilings) and disperse a fine spray of water over an area when activated. The heads are activated by a variety of methods. A common approach activates the heads individually by the melting of a fusible link holding a plug in the head assembly. Once activated, the sprinklers cannot be turned off unless the main water supply is stopped. This approach is called a wet pipe system. These systems are used for storage areas, laboratories, control rooms, and small pilot areas. Another approach activates the entire sprinkler array from a common control point. The control point is connected to an array of heat and/or smoke detectors that start the sprinklers when an abnormal condition is detected. If a fire is detected, the entire sprinkler array within an area... 

The void created by raised panel floors should be provided with smoke detectors and considered as a separate detection zone. The actual design and detection method used depends on several variables including ventilation and routing of electrical/data cables. Passive or active protection may be considered based on the results of a fire hazard analysis. 

Automatic sprinklers are particularly effective for life safety because, they warn of the existence of fire and, at the same time, apply water to the burning area (Hisley, 2003). Standard sprinklers will typically detect a fire much later than a smoke or heat detector. Therefore, a combination of a detection/alarm system and suppression system is a dependable method of protection. 

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