The Basics of Fire Alarm Systems
August 31, 2022
Published by:Andrew Ardianto
Businesses have an investment in the space they occupy. Whether rented or owned, that space is home to technology systems, records, inventory, and, sometimes, cash. Keeping the premises intact must be a high priority. Insurance policies rarely cover the cost of replacing all that gets damaged. This is why fire alarm systems are among those primary investments. What powers them, how fire alarm systems are designed and operated, their modes of notification and their ongoing maintenance are all important selection considerations.
What Is a Fire Alarm System?
What is a fire alarm system and how does a fire alarm work? Essentially, it is one or more fire alarm devices that detect the presence of smoke, fire, or carbon monoxide gas and subsequently alert people using sound and light. A building fire alarm can work in zones or throughout an edifice whether it is a commercial or residential structure. In addition, the system may sync with cell phones, pagers, and other devices to achieve maximum notification for affected individuals. Because buildings and complexes vary in size and scope, so too will fire alarm systems.
Types of Fire Alarm Detectors
Fire detection systems differ in their detection capacity. Alarm systems can be one of the following:
- Heat detecting, IE. activated when sensors pass a set temperature threshold.
- Smoke detecting, IE. activated by ionization or light obstruction.
- Carbon monoxide detecting, IE. set off by toxic CO gas.
- Multi-sensor, IE. optical and heat-triggered.
- Manual call points, IE. turned on by human intervention.
What Is the Purpose of a Fire Alarm System?
The fire alarm system apprehends fires and signals those dangers to building tenants, fire departments, and other first responders. This activity extends from a central and controlled place. depending on their degree of sophistication, fire alarm and security systems can routinely monitor and test their internal components and functions. Boiled down to essentials, these systems are purposed to detect, track, warn and test. Such functions are manifest in a grid of control panels, hardware, and software, each element working in tandem with the others to ensure safety and stability.
A system ordinarily possesses sensors to ascertain heat or smoke, or both. Yet the same system can have an option for manual pull in the event that a building occupant senses the potential fire before the sensors do. In other cases, the alarm system can sense movement in the sprinkler system and take its cue from that. So, the alarm activation is related to other features.
When sensors are tripped or the alarm is set off manually, the system invariably emits loud, sometimes eardrum-piercing, tones so that there can be no mistake as to what is happening. Bright, flashing lights may accompany this deafening noise, rousing the tenants to execute a pre-arranged evacuation plan.
The fire detection and alarm system have evolved from simply sounding a loud commotion. Today's technology allows them to seal off affected areas, signal sprinklers to activate, discontinue air conditioning, and other devices that circulate air and regulate elevator movement. These features enable the system to prevent the diffusion of smoke and flame while keeping personnel safe before help arrives.
In a fire or other emergency, every second counts. A quality fire alarm system is intelligent enough not only to discern the presence of a possible blaze and get the attention of building inhabitants; it should also message the local fire department immediately, without a staffer having to pick up the telephone.
Fire Alarm System Components
The components of a fire alarm system can be few and simple or numerous and elaborate. It all depends on how many functions it has and what the building structure is like. Yet the basic fire alarm system parts are as follows:
Fire Alarm Control Panel
The fire alarm control panel, FACP for short, is the intelligence that governs the system. Boiled down its basic functions, the FACP performs in these capacities:
- Initiator of alerts and notifications - it lets the relevant parties know that an incident has occurred or is in process.
- Buffer against danger - for instance, it can forbid the movement of elevators to floors where smoke and fire are present.
- Inhibitor of smoke - IE. The FACP can turn off air conditioning and ventilation activity so fumes can not proliferate.
- Messenger for help - likewise, the FACP notifies its monitoring station which, in turn, messages first responders.
Although FACPs differ in many ways, there are two major categories under which they may fall: addressable and non-addressable.
- Addressable panels can regulate each connected device individually. It can monitor the device's performance, troubleshoot malfunctions and receive messages.
- Non-Addressable panels arrange all devices (sensors etc.) into zones. The effect of this is that the devices must be checked and evaluated by people in that zone and can not be monitored from a central location.
Addressable panels might be a good fit for a large building that includes areas with little foot traffic or occupancy throughout the day. Alternatively, a building like a hotel, where most of the guests are asleep at night, is also suitable for this type. Non-addressable panels, then, fit better in a facility that enjoys a wide population distribution where personnel is trained on the fire alarm system.
Like control panels, initiation fire alarm devices can be either addressable remotely or non-addressable. Worth noting, though, is that non-addressable components can be linked to addressable connections. In any event, they are critical to the fire detection and alarm system. Initiation devices are detectors and notifying agents:
- Pull stations - every schoolhouse prankster was familiar with pull stations, at least in earlier times. These are the manual alarm activators found in hallways that cause the sights and sounds that tell everyone there might be a fire.
- Smoke detectors - employ sensors to determine if suspicious smoke is in the vicinity. These sensors either apprehend smoke through ion disruption or a change in light patterns.
Smoke detectors can be linked to smoke control systems that move smoke away from vulnerable populations. The placement of smoke alarms and other fire safety tips are important to know for the protection of property. Other options are available as far as initiation devices go:
- Duct detectors - are smoke detectors strategically fitted for ventilation conduits. They can actually block smoke from traveling through the air ducts.
- Heat detectors - respond to higher temperatures associated with fire. They work off either a set temperature threshold or detect a change in heat at a determined rate. A simple example is if the internal temperature in a zone exceeded 95 degrees Fahrenheit, that would trip the alarm. The other type of heat sensor may detect a rise from 70 to 80 degrees Fahrenheit in a few minutes. That jump would be the instigating event.
- Beam detectors - discharge a beam of light over the area of coverage. Should smoke intersect with the beam, the alarm will activate. These sensors are designed to differentiate smoke from some other object passing through the beam.
- Air aspirating/Air sampling detectors - serve as tubular pipelines to a central sensor that is sensitive to the chemical make-up of the air. If the composition changes, the system will sound the alarm. These devices are finely calibrated and might respond to other changes independent of any fire.
Water Flow Switches
Water flow switches employ tiny propelling instruments, paddles if you will, inside of water pipes to move when water begins to flow. In tandem with sprinkler systems, these convey to the alarm system that the sprinkler has been prompted to release water.
The tamper switch has mechanical and electrical aspects to its operation. It signals the system that a water valve has been closed.
Notification devices are those that emanate the sights and sounds of the fire alarm system.
Audible devices involve the ringing of bells, the sounding of horns, and the blaring of sirens to command immediate attention.
Some audible devices are also visual and will radiate flashes of light to accompany the sounds.
Dialers or Communicators
These devices can be located within the system or outside of it. They notify an alarm recipient or monitoring unit to forward the detection message via radio, telephone, or internet.
NAC Power Supplies
Perhaps the most energy-intensive element of a fire alarm system is the notification piece. NAC power supplies, therefore, are located near the control panel and elsewhere to keep the energy flowing.
How Does Fire Alarm Systems Work?
The initiation devices, sensors, and control panels are connected by means of circuits consisting of two or four wires. When the initiation devices apprehend a possible fire, or someone engages the manual pull station, the presence of fire is communicated by these circuits to the control panel. This message will:
- simultaneously go to a monitoring station
- subsequently, go to the local fire station
- put the initiation devices into alarm mode
- alert the building dwellers to safely evacuate the premises
Three States of Fire Alarm Systems
A typical fire alarm system will operate in one of these three states:
- NORMAL - where every component is functioning optimally and no disturbance is detected.
- ALARM - signaling smoke, fire, or related hazard on the property.
- TROUBLE - is an indicator pointing to a short in the connective circuitry or disruption in telephone or communication operations.
Can Fire Alarms Synchronize with Other Safety Devices?
By either legal mandate or personal choice on the part of the property manager, many buildings have fire alarm systems that link up with other systems on site to provide a seamless safety system. Among the corresponding structures are:
- Automatic sprinklers
- Electrical power off-switches
- Elevator control measures
- Smoke dispersion units
- HVAC and ventilation systems
- Remote door locking and unlocking
- Security apparatus
- Public address technology and mass communication.
As the technology improves, the interplay among these safety systems becomes quicker and more efficient. In the case of a fire, occupants appreciate a "smart" building. This sort of integration requires thorough training for responsible staff.
How to Minimize False Alarms
As mentioned above, false alarms can sometimes be the deliberate work of irresponsible individuals. Yet more often, they can stem from a design flaw, an installation problem, or a computer glitch. Inspecting the fire alarm system regularly and troubleshooting promptly can make false alarms a seldom occurrence. Working with experts in fire protection engineering and design consulting in Calgary goes far to cut down on incidents of false alarms and other related malfunctions.
Fire Alarm Inspections
With inspections so vital to the consistency and reliability of fire alarm systems, it is worth noting what this kind of examination involves. Each and every component and connection is checked for signs of wear or disrepair. The control panel is looked over and tested in all its displays and functions. In addition, inspectors assess smoke detectors to ensure they are transmitting signals to the control panel. Next, the pull stations, specialized sensors, and heat detectors receive an analysis for correct performance. Not to be forgotten are the aural and visual notification devices. Circuitry, too, and stand-by batteries are tested before an inspection is over. Professional inspectors will also check the building's power source.
There was a time when the fire alarm consisted of a single person who smelled smoke and shouted "Fire!" Fortunately, the engineering and technology around today allow us to pay better attention before a fire and react more quickly if one breaks out. Fire alarm system basics have certainly changed, for the better. The capacity to monitor property, zone by zone, and sense disturbances in the climate and visual spectrum make an early notification, as well as prevention, the norm instead of the exception. Yet these systems are not always fool-proof, and the good ones need help staying that way.
back to blog
Table of Contents