Fire Alarm System


Fire alarm system is a set of electric/electronic devices/equipment working together to detect and alert people through visual and audio appliances when smoke/fire is present. These alarms may be activated from smoke detectors, heat detectors, water flow sensors, which are automatic or from a manual fire alarm pull station. Fire detection systems are designed to discover fires early in their development when time will still be available for the safe evacuation of occupants. Early detection also plays a significant role in protecting the safety of emergency response personnel. Property loss can be reduced and downtime for the operation minimized through early detection because control efforts are started while the fire is still small. Most Alarm System provide information to emergency responders on the location of the fire, speeding the process of fire control.

To be useful, detectors must be coupled with alarms. Alarm System provide notice to at least the building occupants and usually transmit a signal to a staffed monitoring station either on or off site. In some cases, alarms may go directly to the fire department, although in most locations this is no longer the typical approach. The one major limitation is that they do nothing to contain or control the fire. Suppression systems such as automatic sprinklers act to control the fire. They also provide notification that they are operating, so they can fill the role of a heat detection-based system if connected to notification appliances throughout the building. They will not, however, operate as quickly as a smoke detection system. This is why facilities where rapid notice is essential, even when equipped with sprinklers, still need detection and Alarm System.

The most basic alarm system does not include detection. It has manual pull stations and sounds only a local alarm. This level of system is not what is typically used; it relies on an occupant to discover the fire, which can cause a significant delay. The more quickly you want to be notified of the fire, the more costly the system you must install. Speed of detection is expensive. The slowest system to detect a fire is a heat detector, which is also the least expensive. An air-aspirating smoke detection system provides the most rapid indication of fire, but these systems are five to 10 times as expensive.

Where to Start When Choosing a System The type of fire detection and alarm system used in your facility should be based upon your fire safety objectives.

These objectives flow from a risk assessment of your facility and operation. Your tolerance for risk and how much you can afford to lose is an important part of this process. The issues within a hospital are not the same as they are in a warehouse. In a facility where life safety is the major concern, such as hospitals where patients may not be able to evacuate on their own, early warning is essential. Dormitories, hotels, and other facilities where occupants may be sleeping when a fire starts also require that a system provide more rapid notification. In a warehouse, where the occupants will be awake and aware and there will most often be fewer of them, the alarm system often does not need to provide notice as early. In a generally unoccupied structure where life safety is not a major issue, detection of a fire can be slower without significantly increasing risk. When selecting a system, you also must consider the ongoing commitment that will be required over the life of the system. Inspection, testing, and maintenance requirements for these systems are extensive. Meeting these requirements over the life of a system usually will cost more than the original installation.

Detectors are available in a wide variety of types. The major categories are heat, smoke, and flame detectors. Within each category are numerous additional specific types. The discussion here will be limited to those most commonly used for building fire detection and alarm activation. Several varieties of detectors, such as flame detectors, are used primarily to activate suppression systems.