An Introduction to Fire Alarm Systems
Ugochukwu Ebu

Ugochukwu Ebu
CEO at Off-Field Concepts Ltd.

5 September 2016
A key aspect of fire protection is to identify a developing fire emergency in a timely manner, and to alert the building’s occupants and fire emergency.

Fire alarm systems (also commonly called smoke alarm and a smoke detector) provide a means to detect and identify a fire or a potential fire outbreak in a building, warn the occupants of the building about the fire via audible alarm and potentially notify emergency response professionals. The main components of a fire alarm system are typically the smoke detectors (and other detectors like heat, gas detectors), manual call points (also called ‘break glass’) which enable a person who physically detects fire to raise the alarm, bell or alarm sounders, flashers, and control panel (central control and indicating equipment) which is the brain of the system. Some advantages of fire alarms include an early warning benefit and the potential to save life and property, low cost and the opportunity to place the device in chosen locations. It is a key recommendation in any fire prevention plan.

The fire alarm systems we use today may involve smart sensors, intelligent control panels and integration with other building services, but the core essence of fire alarm systems hasn’t changed – give the  the occupants of buildings an early and clear warning of a fire.

The main components of a fire alarm system are the smoke detectors ( and other detectors like heat, gas detectors), manual call points which enable a person who physically detects fire to raise the alarm, bell or alarm sounders, flashers, and control panel which is the brain of the system.

Smoke Detector Fire Alarm Systems
Smoke Detectors
Fire Alarm Break Glass
Manual Call Points

Types of Fire Alarm Systems

There are two main types of fire alarm – Conventional and Addressable.

Conventional (also four-wire) fire alarm systems are less expensive to purchase and are mostly used in smaller properties such as shops and restaurants. In this system, a building is divided into a number of detection zones with one or multiple detector in a zone. All the detectors and manual call points in the zone are hardwired to a dedicated circuit on the control panel. Each bell or alarm sounder in this system is connected via a separate two-core wire to a dedicated loop. When a detector is activated (just another way of saying when it detects smoke or fire), the control panel indicates the zone from which that detector was triggered. The drawback is that the respective zone has to be manually checked in order to pinpoint the exact source of the alarm. This can be time-consuming in an emergency, especially in zones with a large number of devices.

A modification of the four-wire conventional system is the two-wire fire alarm based on the same technology as the conventional system. A two-wire system uses the same set of two-core cables to connect all the devices – call points, detectors, and bell – in a single zone to the control panel. Two-wire systems are more functional, flexible and overall, less expensive to install and operate than their four-wire counterpart but cost more to purchase. Conventional systems only provide detection information particular to a zone but not the individual devices in the zone.

Addressable Control Panel
Addressable Fire Alarm Control Panel
Fire Alarm Systems Conventional Control Panel
Conventional Fire Alarm Control Panel

In contrast, addressable fire alarm systems provide specific information on individual detectors. Addressable systems are intelligent and they employ one or more single loop wiring to connect different types of detectors or other initiating devices. Each device (detectors, call points, etc) have a unique address or identifier. The control panel regularly queries every connected device which in turn report their precise location, health status, errors or fire and the relevant information from the devices are displayed by the control panel. Addressable systems have greater flexibility, control, and speed of identification than conventional systems but they are more complicated and more expensive to deploy. They are best suited to large commercial buildings and premises with intricate networked requirements.

Other types of fire alarm system are wireless fire alarm which are battery-powered and sometime radio-linked, and aspirating smoke detection systems. Aspirating smoke detection systems detect smoke by using a fan to draw in air from around a building via a network of sampling pipes and holes, and passing this air through a highly sensitive precision detector that analyses it and generates warning signals of potential fire when it detects smoke particles. They are most useful where early warning is required but are very expensive to install and maintain.

Wireless Smoke Detector
Wireless Fire Alarm

Dangers of Fire

Smoke inhalation, not burns, is responsible for most deaths in a fire as smoke rapidly incapacitates people, degrade visibility and diminish the chances of fire victims reaching otherwise available exits.

Smoke is dangerous because it contains particles at various stages of burning that can penetrate the respiratory systems and lodge in the lungs. Toxic gases in smoke such as carbon monoxide can deplete the blood’s oxygen supply. Fire in the presence of PVC pipes, vinyl materials and other household items produces hydrogen cyanide and phosgene which can respectively lead to obstruction of cellular respiration and death by pulmonary edema. It also contains vapors that can be poisonous when inhaled or absorbed through the skin.

Since fire needs oxygen for combustion, oxygen levels can deplete quickly by combustion or displacement with other gases generated by the fire. At oxygen levels of twelve percent, fatigue, headache, nausea and dizziness set in, followed by unconsciousness at nine percent, and respiratory failure, cardiac arrest and death at six percent.

Heat and thermal radiation are also among the inherent dangers of fire due to their effect on people and property. One breath of air that is hot enough or containing superheated gases can burn the respiratory tract and kill.

The effect of fire in the workplace can be devastating. Furniture, discarded packaging, loose paper, waste bins are ready fuel for fire in the workplace. Other significant risks also come from overloaded or overheated power extensions, damaged power cords and computer equipment.

The damage and hazards caused by fire in an industrial setting can extend to surrounding communities. Regular, scheduled fire risk assessments are critical to the prevention of fire in offices and industrial settings.

At home where we normally feel safest is actually the most likely place for one to die in a fire. Heating equipment, Candles and cigarettes, poor electrical connections and overload pose significant dangers. What about cooking? How many times have we walked away from the stove, distracted, and forgot that we left food cooking on the stove? Cooking also poses significant risks because it is something we do all the time. This is the strongest case for homes to install fire alarm systems and extinguishers or fire suppressants.

Fire Infographic

Benefits of Fire Alarm

The obvious benefits of fire alarm systems include the early warning benefits that can lead to saved lives and property. Fires can occur anywhere and at anytime. Today’s systems can increase the evacuation time for the occupants of a building so that they are able to get away before the fire spreads out of control. Other benefits include:

  • Automatically alerting emergency fire & medical services so help can quickly get to those in need. It can also alert other key contacts such as building owners and facility managers.
  • With the precision of addressable systems, fire safety personnel know exactly where the fire is and thus have an easier and less risky job combating the fire and evacuating people from the building safely.
  • Employees will feel more comfortable, secure, and happier working in a place that has an appropriate fire alarm system.
  • If an auto-triggered fire suppressant systems like sprinklers are installed as part of your fire alarm system that includes suppressing a fire such as through a sprinkler system, it reduces the risks to life and the exposure of a property and its occupants to the hazardous prospects of a fire outbreak.
  • With more hospitals and medical facilities embracing fire alarm systems in Nigeria, the feeling of safety within these facilities is at a high. Especially as they are integrated with other advanced system which enhances response time like gas detection and voice evacuation systems. Early fire detection is critical to the timely evacuation of patients in a hospital, especially patients who are unable to move themselves.
  • Fire alarm systems can easily be integrated into a remote monitoring system either onsite or offsite.
  • It can be integrated with CCTV surveillanceAccess Control and other Security and Safety systems in many full-serviced buildngs.
  • Additionally, fire alarm systems have a low entry cost and also the flexibility of where to place the system and its components.

So it’s often best to install fire alarm components on every floor of a building The fire alarms can be installed just about anywhere in a commercial building and best of all the fire safety measure is highly cost effective for smoke and fire protection. But it is never enough to have a fire alarm system installed. Scheduled, regular testing of all components is vital to the effectiveness of these systems if they are to be relied upon for the protection of lives.

Home Fire Tips

History of Fire Alarm

Fire alarm systems have come a long way with a remarkable history. The first fire fighters were organized town and community members who worked in scheduled shifts walking through their home towns with bells and whistles they could ring or blow for assistance when a fire was spotted. New York, in the United States, already had this practice in place as far back as 1968. Although it was mostly difficult tracing the location of the manually sounded alarm, this system was undoubtedly helpful for the safety of the town. Fire alarms became a little more advanced in the 1800s with the positioning of bell towers in strategic parts of cities to warn off people of a fire.

Dr. William F. Channing, assisted by Moses G. Farmer, invented the first fire alarm system in 1852 and the first alarm received by the system occurred the following day. It was a telegraph system that was made up of three bells and three box circuits, 16 alarm bells, 40 boxes and a central office mechanism. With the exception of adding electronic decoding terminals to it in 1988 the system has been largely unchanged to present day. The telegraph system employed two alarm boxes with a telegraphic key to report neighborhood fires. Someone had to crank the handle that was attached to the box, releasing the key to send out a message to the central alarm station. At the central station, the telegrapher would then send out the address of the location to the fire department.

In 1890 Francis Robbins Upton designed and patented the first electric fire alarm. Although his invention received little attention and was largely disfavoured, it soon became apparent that the need for this device was growing.

By 2014, fire alarm systems had evolved to operate independently of any electrical utility lines or telephone lines. Today, the newest development of the fire alarm system has been the addressable head. Before the addressable head, there was a control panel with an alphanumeric display that indicated what zone was being affected. With the addressable head, the origin and location can be pinpointed directly.


In most countries, fire alarm systems are required by law especially for all public buildings. National building and fires safety codes also require that employers and/or building owners or occupiers conduct and maintain a fire safety risk assessment and that adequate and appropriate fire safety measures, including fire detectors and alarms, are in place to minimize the risk of injury or loss of life in the event of a fire. The National Fire Safety Code regulates the use and requirements of fire alarm systems in Nigeria.

Aspirating Fire Alarm Systems
Aspirating Fire Alarm System

Problems with False Alarm

False alarm or false positive from fire alarm systems can be quite challenging and sometimes an absolute nuisance. Regular, scheduled maintenance is the best way to minimize false alarms. False alarm can have huge impact on business resources and emergency service delivery, and can increase the risk of injury to the occupants of a building.

Other undesirable effects of false alarm includes complacency in real emergency as a result of psychological conditioning, loss of productivity from unnecessary disruption to business activities or life in the home, panic. It can also lead to delays in real emergency and increases the risk of injury and accident to firefighters and the general public. It is thus essential that fire alarm systems are well maintained and operate efficiently at all times.


The modern fire alarm system is capable of detecting smoke and heat from a small flame, water flow in a sprinkler system or an activated pull station, and reporting this information to on-site personnel via dedicated phone line to any location in the world. 

With the growing influence of nanotechnology, wireless sensory networks, home automation and smart building solutions, intelligent, more efficient and easier to use sensors and fire alarm products are expected to make their entry into the market soon. Whilst the technology today are only able to notify people, and not necessarily direct them, evolving smart building technology will likely introduce the capacity to guide the occupants of a building to the appropriate exit even in the poor visibility of a smoke filled room. Using broadband noise, directional sound devices may clearly communicate the location of exits. These devices employ varying tones and intensities to provide easy-to-understand, intuitive cues for finding safe exits. We might also see a shift in focus from technical innovation to improvements in fire alarm application and usability, and the adoption of a universal fire alarm control user interface.

The Nigerian fire alarm market, for instance, has seen an increased adoption by hospitals and hotels due to rise in security issues and accidents. A possible enforcement drive by government as threatened by the Controller-General of the Federal Fire Service, Mr Olusegun Okebiorun in 2013, may further fuel market demand over the coming years.

Overall, on the international scene, the fire protection systems market size is expected to grow from USD 47.96 Billion in 2015 to USD 98.24 Billion by 2022, at a CAGR of 10.1% between 2016 and 2022, according to the MarketsandMarkets forecast.


Fire alarm systems can seem straightforward when you consider the ease of installation, but it can present some complex moral, operational and legal responsibility. There has also been some recent updates to the technology over the last few years worth noting. The underlying principles remain the same. Alarm sounders will give off an audible sound when smoke is picked up by a smoke detector or when a person operates a manual call point and the ultimate goal is to warn other people in the building that there may be a fire and to evacuate immediately. Increasingly, fire alarm systems incorporate remote signalling equipment which would alert the fire brigade or other available emergency response services.

Every building needs a fire alarm system. Lives and valuable assets have been saved because of the early warning benefits of fire alarm systems. They are affordable and, when used properly and maintained regularly, are very reliable.

This article is the first of a series as part of our Fire Safety Awareness Campaign throughout September 2016.

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