How to Design a Fire Alarm System by Nimal Tissa Wijetunga

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When designing a fire alarm system to protect your building, there are many factors which you should take into consideration. Unfortunately, if you want a reliable and safe system, mere compliance with the legal requirements may not be enough. To make sure your building is protected, you should determine the primary purpose of the fire alarm while considering all the features of your building. How many people are working in it simultaneously? Is it a listed building or a modern office block or a Warehouse or an Industrial Facility? And, finally, what do you want to achieve? High cost-effectiveness or convenience in monitoring the building? Depending on your needs, there are different types of fire alarm systems that you can select.

Conventional Fire Alarm System

This traditional system is the most common choice, especially among residential clients and small business owners. It’s suitable to cover small areas such as private homes, restaurants and shops. Unfortunately, the conventional system is unable to show you the exact location of fire. That’s why it’s suitable to cover mostly small areas such as private homes, restaurants and shops. Bigger buildings can be divided into zones (for example, the first floor could be one zone, etc.) giving you a general idea of the fire location. Keep in mind, though, that a device covering each area requires a separate wire, which can increase installation costs in bigger buildings.



Despite its simplicity, conventional fire alarm systems are highly reliable. They are also affordable and cost effective, especially in small buildings, in which one or two zones are enough to cover the whole area.

Addressable System

This fire alarm system is more sophisticated compared to its conventional counterpart. Instead of a separate wire for each device, all of them are connected to the main control panel using a loop. This lowers the installation cost down, especially in large buildings. Additionally, it’s easy to find the exact location of fire as each device has its unique address in the system.

Addressable systems are quite easy to maintain because both technical condition of the system and all the alarms can be monitored using a convenient management panel. The system is also fully programmable what together with a loop wiring makes it easy to connect a new device, what’s especially important if you plan on redesigning the building in the future.

Although the initial cost of this system is higher than that of a conventional one, it’s much easier to install and is a perfect choice for large, multi-storey buildings.

Wireless fire alarm system

In this system, all devices are communicating wirelessly; no wiring in the building is required. This makes it an excellent choice for listed buildings, in which installing wires may require special permission. Similarly, those who value flexibility (location of each device can be changed easily) or simply do not want to make extensive installations will find this system a perfect fire protection.

Their high initial cost quickly offsets as there’s no need to run the cables, what allows saving on labour, time and potential damage to the building during the installation. Even though the system is battery-powered, it is highly reliable, and there’s no risk of signal collisions as it is designed to eliminate any signal interference.

What else is important?

Apart from technical specifications unique to each system, there are a few factors which are similarly important regardless of your selection. The first important factor is the speed in which the system reacts to fire outbreak. In the case of fire, every second counts and allows for evacuation of people. The earlier a fire is detected, the easier it will be to extinguish it, minimizing the damage.

Another problem that affects many fire alarm systems are false alarms. Check if the devices in the system of your choice are reliable enough to distinguish between dirt, steam, and the actual smoke easily. The fines imposed for each false alarm may exceed the initial savings on the chosen system; that’s why you should make sure that you select quality devices only and most importantly Listed and Approved by the Third Party Certification bodies for the purpose. Moreover, each false alarm forces people to stop working and leave the building.

Similarly, it is extremely important to consider the detection devices suitable to the particular environment conditions prevailing in the building and the ceiling or roof height where those are going to be installed to prevent false alarms as well as “faulty” conditions in the panel connected therewith and ineffectiveness respectively.

Last but not least – make sure that all of the occupants in the building can hear the alarm. If there are many people inside it, it’s a good idea to choose a fire alarm system which allows you to communicate with those leaving the building, to keep the evacuation process as smooth as possible.

Further, the effectiveness of a fire detection system specifically by large facilities or spread out operations can be enhanced by monitoring the central fire alarm panels within the facility and connecting it to a remote monitoring station manage by General Headquarters of Fire Prevention on 24 hour basis for quick attendance by Public Fire Brigade.

Designing a fire alarm system that perfectly suits your building is not an easy task and can be quite costly. Despite the initial expense, you should never try to save money on your safety and the safety of others. The installation and maintenance costs of a quality system are very low compared to potential losses caused by the actual fire, and the cost can be highly optimized if you design the system with your building and its occupants in mind.

Written by:

 Nimal Tissa Wijetunga

  • Fellow of Institute of Fire Engineers, UK. (FIFireE)
  • Professional Member of Society of Fire Engineers, USA.(MSFPE)
  • Member of the Institution of Risk Management, UK.(MIRM)
  • Certified Fire Protection Specialist, National Fire Protection Association, USA.(CFPS)

(The author of this Article has over 25 years hands on experience and exposure on Risk Engineering, Fire Engineering and Health & Safety to all occupations such as road side shops, High Rise Buildings, Warehouses, Distribution Centers, Logistic Facilities, Industrial, Oil & Gas Facilities etc. through Insurance Companies, Fire Safety Consultancies and the Construction Industry Internationally and recent times in Sri Lanka. 


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