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How Fire Alarm System Works

If you find yourself searching for ‘fire alarm companies near me in Orange County’ or ‘fire alarm service companies near me’, this means that you are most likely looking to install a new fire alarm system, upgrade an existing one or service one in your building. You are already familiar with how important fire alarm systems are, be they regular or monitored. However, choosing the right type depends on your understanding of how fire alarm systems work. There are different categories and types, which correspond to certain variants of commercial buildings and there are laws and requirements prescribing their use accordingly. Here is a brief overview of how fire alarm systems operate.

Two categories: automatic and manual

The basic division of fire alarms is based on how they activate. Automatic fire alarms activate when they detect heat, smoke or water flow through the sprinkler system and sound an alert throughout the building. Manual ones require people to break a glass and pull the lever at certain stations around the building when they see a fire.

How fire alarm systems work depends on its type

Conventional fire alarms

Conventional fire alarm systems are systems based on utilizing hardwired zones. These systems vary from 1 zone and up depending on the manufacturer. Devices connected to these zones or IDC (Initiating Device Circuits) are grouped together and cannot report specific device information or location unless a zone is designated to a specific location. As in the case of addressable systems, conventional systems can be wired Class A or Class B. The difference when wiring Class B requires an end-of-line device resistor which is needed for wiring supervision.

Addressable Fire Alarms

They sometimes go by another name – ‘intelligent alarms’ because of the options they bring to the table. One of them is choosing between an automatic and a manual fire alarm. Addressable fire alarm systems are systems which have the capability of reporting the specific status of each device back to the FACP (Fire Alarm Control Panel). Each device reports its unique address, descriptive designation as well as status, ie. Device XXX is dirty /needs service, in alarm or in trouble plus a host of other information which depends on the manufacturer.  These devices are manufactured with this capability and cannot be interchanged with conventional type. Addressable devices typically have dip switches, rotary switches or need to be programmed in order to communicate with the FACP. Additionally, these devices communicate on an SLC (signal line circuit) loop which allows for either Class B or Class A wiring.

Hybrid Fire Alarms

As the name suggests, they combine the properties of the two aforementioned types of alarms to create a hybrid.

Stages of fire alarm operation


This is the well-known part of how fire alarm systems work – when an initiating device, i.e. heat, smoke, manual pull station or other automatic device has been activated. The alarm system activates its notification devices i.e. horns, strobes, bells or speakers to warn the occupants or workers to leave the building.

Sending the signal

When the alarm is activated, a signal is sent through dedicated phone lines, the internet or cellular towers directly to a Central Station monitoring company. The Central Station monitoring company has the responsibility of monitoring the system and communicating its status to the Fire Department or the customer.

Calling the authorities

As soon as the Central Station monitoring company gets the signal, they are responsible for notifying the fire department to dispatch to that address.

Calling the customer

Upon contacting the Fire Department, the monitoring company also has to call the customer to notify them that firstly, they have received the signal and secondly, that help is on the way at that time.

Red Truck: leading Orange County expert on how fire alarm systems work

Fire alarm systems are required by code in commercial buildings and when installing them you need to choose the right one according to the enforced law. When you leave the whole process to Red Truck Fire & Safety Company, you can rest assured knowing your safety is in good hands. Our seasoned technicians are well versed in fire alarm installation and inspection as well as the applicable code and laws so you can relax and leave everything to us. Just call us and we’ll offer you the best possible solution at the most affordable prices!

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