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Do Fire Alarms Work Without Power?

Fire alarms are devices that sense smoke as an indicator of a potential fire in the building. They generally issue a visual or local audible sound so that everyone can take necessary precautions or protocols to vacate the building.

A fire alarm can be either hard-wired or battery-powered but cannot work without power. Different types of fire alarm systems operate differently based on their structural framework. This article discusses everything you need to know about fire alarm systems including how they work, different types, and available powering mechanisms.

How Do Fire Alarm Systems Work?

emergency light wall panel and alarm speaker
An effective alarm system is made up of a control panel, a primary power supply, initiating devices, building safety interfaces, notification appliances, and emergency voice alarm communication systems (EVACS). The control panel is tasked with system integrity and monitoring inputs to control the response of associated fire suppression systems and relay vital information across connected devices. Fire alarms are powered by non-switched power sources controlled by your power company. Other commercial buildings have a dedicated branch circuit that supplies power separately to the fire alarm system to avoid overloading the main system of your facility.

A secondary power supply system is also installed to keep your system alert during a power outage. It can be made up of automatic generators, lead-acid storage batteries, or other emergency power sources. Initiating devices can be activated either manually or automatically depending on the setup. Audio devices or flashing strobe lights are notification appliances alert people to an emergency to assist them in safety. EVACS may produce verbal commands during an emergency to provide specific instructions on how the occupants should leave the building.

Classifications of Fire Alarm Systems

  • Automatic and Manual Fire Alarm Systems

Devices that respond to physical changes in the building initiate this type of alarm system automatically. It is capable of detecting smoke, heat, or carbon monoxide, which are possible indicators of a potential fire. Manual fire alarm systems are initiated using manual pull stations or call points located near exits. However, there is no reason to exclude automatic or manual initiating devices from a fire alarm system.

  • Conventional and Addressable Fire Alarm Systems

Conventional fire alarms operate as a single unit in a building. This means that they cannot detect the exact location where possible smoke or fire has been detected unless it is inspected. However, addressable fire alarms are designed with an exclusive address for every alarm detector linked to the control panel. This setup allows the staff or fire personnel to identify the exact location of the danger.

  • One-Stage and Two-Stage Fire Alarm Systems

This type of fire alarm system is designed to alert the occupants in a building about potential smoke or fire. This means that once the sensor alarm has been triggered, everyone will be notified at the same time of possible danger through emergency audio devices or flashing strobe lights. However, a two-stage fire alarm system alert only authorized personnel to take action before alerting everyone in the building about an emergency.

Hardwired vs. Wireless Fire Alarms

A fire alarm system needs to be connected to a power source since most sensors and other system components rely on it to function properly. For this reason, a fire alarm system can be hardwired to your home’s power supply or connected to a battery. Wireless fire alarms systems are battery-powered and can be installed in a matter of minutes. However, you need to replace the batteries more often to keep the system operational, as it is their only source of power.

Hardwired fire alarm systems are installed by a professional electrician and connected to the main power grid of the building. They continue to operate normally unless there is a power outage. However, most hardwired fire alarm systems are usually connected to an emergency power source such as an automatic generator or lead-acid storage batteries to provide backup during power outages. This makes them more efficient than battery-powered fire alarms, which only rely on batteries as their only source of power. The alarm may sound dull as batteries weaken, so you may have to replace them more often for the system to be effective.

Fire alarms and smoke detectors have become life-safety systems that allow people to take action during emergencies like potential fire in the building. Regardless of the style or design of a fire alarm system, it is dependent on a source of power for the sensors and other integral parts of the system to execute the necessary functions.

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