Fire Alarm System Components: The Elements of Your Project

By Andrew Erickson

August 7, 2022

Understanding what a commercial fire alarm system consists of and how it works will help you justify the costs associated with its installation and operation. Even life safety systems have to find budget somewhere.

Because our Prism LX oversees entire fire alarm systems, we naturally do a lot of thinking about the underlying components.

Remember that an evaluation of your requirements, by experts in the fire alarm system industry, will help to determine what types of equipment and which fire alarm system will best suit your needs. After you've read this overview, be sure to give us a call to discuss your project.

DET 6C emergency fire pull box
Pull handles like this one are a manual protection device. Although these used to be the core of any detection system, modern smoke and fire detectors mostly make human-interface devices like this a redundant backup.

Components of a Fire Alarm System

Control Panels

Fire alarm control panels (FACP) are the main monitoring component of any fire alarm system. In other words, it’s “the brain”. When a fire occurs, a device that detects fires sends a signal to the control panel.

The panel then decides what action to take. Typically, an alarm is activated. The response can also include other predetermined actions, such as closing doors, recalling elevators, and notifying the local fire department.

The control panel can be customized to suit your specific requirements.   

Initiation Devices and Notification Devices 

Initiating devices can either be manual pull stations, smoke detectors, flame detectors or heat detectors.

Once a fire is detected, they send an alert to the main control panel of the fire alarm system, which then prompts the notification devices to sound an alarm in the form of horns, lights, chimes, or bells.  

There are both manual and automatic initiating devices.

Pull Stations

Pull stations are those little red boxes, labeled “FIRE”, mounted on the walls by stairwell doors or exit doors. They are manual fire protection devices that, when the lever is pulled, activate an alert to the fire alarm system.

Ademco fire pull box
This manual pull box, from Ademco, is universally recgonizable. It allows anyone who sees a fire to quickly report it.

Smoke Detectors

Smoke detectors do exactly what their names imply. Types of devices include battery-operated or hard-wired (with battery back up). When they sense smoke, they send an alert to the control panel, which signals an alarm. 

Simple smoke detector
The standard smoke detector is another common automatic fire protection device.

Aspirating Smoke Detection Systems

One of the most reliable detection types, aspirating smoke detection systems are highly sensitive. They utilize a fan that draws air in through sampling pipes. The air samples are then analyzed for smoke particles. They can detect smoke before it's even visible.  

Flame Detectors

Flame detectors can mostly be found in buildings and factories that deal with highly flammable products. The presence of a flame will activate the flame sensor. In response, it will initiate whatever action it is programmed to do. It might sound an alarm or activate a fire suppression system. 

Heat Detectors 

Heat detectors can typically be found in warehouses and commercial buildings where the intent is to protect the actual structures and their contents from fire damage. Depending on how it's programmed or hardcoded, it will trigger at different points. Typically, when the temperature reaches 135 degrees F (57 C) or 194 degrees F (90 C), the Heat Detector will notify the control panel to trigger an alarm.

Heat detector, not a life safety device
A heat detector is an automatic protection device that requires no human interaction. Be sure to choose equipment that meets NFPA or other requirements. As you can see, this one is non-compliant and labeled "Not a life safety device".

Wet Pipe Sprinklers

Wet fire sprinkler systems are the most commonly known sprinkler system. Have you ever seen a movie where someone holding a flame close to the sprinkler head activates the sprinklers and all the characters get drenched? That is almost exactly how wet fire sprinkler systems work.

Except, in the movies, all the sprinklers get activated. In reality, only those exposed to the fire will discharge the water, which helps reduce additional damage. This type of fire sprinkler system is typically found in schools, office buildings, and high-rise buildings. 

Dry Pipe Sprinklers

When activated, dry pipe sprinkler systems discharge water like the wet pipe fire sprinklers. The difference is that dry pipe sprinkler system pipes are filled with pressurized air instead of water.

When a fire is present, the air pressure drops. This triggers the valve to open and release the water. It is important to use this type of system in areas where temperatures can get low enough to burst pipes.

You will see dry pipe fire sprinkler systems in outdoor parking garages, unheated buildings, and warehouses.  

Pre-Action Sprinklers

Pre-action sprinklers act similarly to dry pipe sprinklers, where their pipes are filled with pressurized air. They won’t get activated, though, until a smoke or heat detector first detects a fire.

This type of sprinkler system is often found in museums and libraries, or other buildings filled with valuable items. This two-step process was created in case of false alarms or mechanical failures to help alleviate additional damages from water.

Fire Suppression Systems

Rather than using water, fire suppression systems use chemical, gaseous, or foam agents to suppress fires. These systems are typically found in industrial plants, facilities that handle highly combustible substances or large amounts of electrical equipment, or in commercial kitchens.

Carbon Dioxide

Mostly installed in buildings not occupied by people, carbon dioxide (CO2) fire suppression systems quickly and effectively extinguish fires without causing damage to equipment or property. Obviously, they present a huge risk to life safety if used in occupied areas.

Dry Chemical Suppression

Dry chemical suppression systems are used to extinguish fires caused by flammable/combustible liquids. They are super-fast acting in suppressing fires because they are pressurized with nitrogen, which discharges the dry chemicals.

Wet Chemical Suppression

Typically known as the “traditional” fire suppression system, you will find this type of system most often in commercial kitchens. The wet chemical agents that are discharged when combined with grease create a soapy layer. This seals it off, which prohibits oxygen from fueling a fire. 

Clean Agent Fire Suppression

Clean agent fire suppression systems are quick acting and directly discharge toward the fire-filled zone. The released agents dilute the oxygen content enough to stop the fire. This helps to limit the damages to equipment and irreplaceable assets. This type of system is typically installed in buildings like libraries, museums, archives, or server rooms.  

Types of Fire Alarm Systems

Conventional Fire Alarms Systems

Typically found in smaller buildings, conventional fire alarm systems are less expensive than most other alarm systems. These systems separate a building into zones with multiple detectors.

When an alarm is activated, the control panel alerts to which zone the alarm is from, but not the specific detector that was triggered. 

DET-16 Telegraph Encoder
Legacy fire alarm components still run on telegraph taps for communication. This DET-16 device is a way of ingesting telegraph signals into a modern digital fire alarm management system.

Two-Wire Fire Alarms Systems

Also found in small buildings, two-wire fire alarm systems offer more flexibility and faster response time than conventional systems. This enables detectors, alarms, and beacons to run on the same two wires. That minimizes installation costs.

Analogue-Addressable Fire Alarm Systems

These highly “intelligent” fire alarm systems provide more precise detection of where the fire is located because each call point has its own distinctive address. Analogue-addressable fire alarm systems are typically designed for large commercial buildings and are generally more expensive. 

Hybrid Fire Alarm Systems

Hybrid fire alarm systems combine attributes from addressable and conventional systems. They usually utilize hardwired zoning (Conventional) and offer alternative monitoring options (Addressable).

Wireless Fire Alarm Systems

Wireless fire alarm systems are becoming increasingly more popular. They offer more flexibility for the same level of protection.

Without the need to lay cables, installations are quicker. They are portable! They can be relocated anywhere, at any time.

If the electricity goes out, no worries! Wireless fire alarm systems use batteries, so they will continue to work for you. Just don’t forget to test and/or replace them from time to time.

AM radio fire alarm signal receiver
This Mark VI 1221 AM Radio Receiver can receive radio-based fire signals and bring them under your Prism LX monitoring umbrella.

Monitoring 

When the Fire Alarm Control Panel (FACP) notifies the local Fire Department, it was classically done using an analog phone line. With the advancement of technology, more companies are turning toward using wireless phones.

The NFPA has updated their requirements to accommodate this trend. They now require all commercial fire alarm systems to have at least one landline connected to the panel. The other can be connected to Voice over Internet Protocol (VoIP). 

Maintenance & Testing

As with anything, proper maintenance and testing will ensure your alarm system will perform to its highest ability to protect your people and assets.

The National Fire Protection Association (NFPA) has regulations regarding the scheduling of testing the various components and equipment associated with your fire alarm system. Depending on environmental conditions and the manufacturer's guidelines, testing might need to be done weekly (visual inspections of fuses, power supply, LEDs), monthly (batteries), bi-annually (smoke or heat detectors) or annually (all equipment).

The last thing you want to happen is to have a fire and not hear the alarm, not have the sprinklers activate, or not have the fire department notified! 

Compliance

All properly installed fire alarm systems will adhere to the National Fire Protection Association (NFPA) Codes and Standards, as well as any state and local building codes.

Give me a call to discuss your fire alarm project

Whether or not you need Digitize equipment, I'll help you sort through your project requirements.

Even if you have detailed questions that get beyond my expertise, I have the entire Digitize engineering team available for you.

Give me a call at 800-523-7232 or email me at info@digitize-inc.com.

Andrew Erickson

Andrew Erickson

Andrew Erickson is an Application Engineer at DPS Telecom, a manufacturer of semi-custom remote alarm monitoring systems based in Fresno, California. Andrew brings more than 15 years of experience building site monitoring solutions, developing intuitive user interfaces and documentation, and opt...