25/04/2023

Main Types of Fire Alarm Systems

There are five main types of fire alarm systems. Each will have its application within the design process, and the correct identification for the most appropriate system is critical to ensuring buildings get the best possible active fire detection system installed. The five categories can be divided into conventional fire alarm systems, hybrid two-wire conventional systems, addressable systems, aspirating smoke detection systems and radio-controlled fire systems. Within this blog, we will detail each of the different types and their most common application.

 

Conventional Fire Detection Systems

A conventional fire alarm system is the most basic commercial system available – and generally the lowest cost system in terms of parts. The system operates on single-wire basis with detectors and manual call points being located along the wire, finishing with an End of Line Unit (EOL).

Advantages of Fire Detection Systems

The advantages of a conventional system are that they tend to be cheap to put in place, providing a simple solution for buildings of low risk and simple structures where there are few rooms.

Disadvantages of Fire Detection Systems

The main disadvantage is the volume of cable required to be installed – meaning that they can be labour-intensive to install and commission. Faults and alarms also knock out entire zones rather than individual devices – this means that a fire/fault can only be identified in a single zone rather than pinpointing a specific location within the building.

It is a requirement of conventional systems that alarm circuits be separated from sounder circuits to ensure the sounders can continue to function when a zone is activated.

 

 

Hybrid Two-Wire Conventional Systems

A two-wire fire alarm system is a more advanced conventional system where the fire alarm operates on a radial circuit. Two-wire systems eliminate the need to separate the sounders and detection devices operating to an EOL similar to a conventional system.

Advantages of Hybrid Two-Wire Systems

The advantage of a two-wire system over a conventional system is the significant reduction of cabling required as the sounder circuits and detection circuits can be combined. This also allows for the introduction of combi-units such as smoke detectors with sounder bases etc.

Disadvantages of Hybrid Two-Wire Systems

The disadvantages remain broadly similar to that of a conventional system, with a high volume of cable still being required, and a relatively low intelligence within the system, preventing specified feedback or a distinction between fault and alarm. Alarm and Fault signals can also only be identified zonally rather than device specifically.

 

Addressable Fire Alarm Systems

An addressable fire alarm system is more advanced than conventional and hybrid two-wire systems, where the fire alarm operates on a loop circuit rather than a radial circuit (all devices and cabling start and end at the control panel rather than ending at an End Of Line unit). This allows for major advantages, such as the continued operation of the detection system in the event of a fault on a single device or loop.

Advantages of Addressable Fire Alarm Systems

The advantages also go beyond the cabling aspects. Addressable systems, as the name suggests, allow each device (whether it is a sounder or detection device) to have a unique address which is identifiable on the control panel. This allows for a much more accurate location of an alarm or fault as the responsible person can literally read off the devices that are signalling from the panel display screen – with further information available to them, such as fault or fire.

Disadvantages of Addressable Fire Alarm Systems

The disadvantages in direct comparison to conventional and hybrid two-wire systems remain rooted in economics. With the intelligence of the devices comes a more significant price for the purchase of the equipment – but for the coverage and protection provided, this is, in most cases, worth the additional investment!

 

Aspirating Smoke Detection Systems

An Aspirating Smoke Detection (ASD) System is a type of smoke detection system that uses a network of pipes to actively sample air from an area and detect the presence of smoke particles.

The system works by using a fan to draw air through a network of pipes and into a detection chamber, where it is analysed for the presence of smoke particles. The system is highly sensitive and can detect smoke particles at very low levels, making it ideal for use in applications where early detection of smoke is critical, such as in data centres, museums, and archives.

The ASD system can also provide information about the location of the smoke within the monitored area, which can help in identifying the source of the fire and in taking appropriate action. The system is often used in combination with other fire detection systems, such as conventional smoke detectors or heat detectors, to provide comprehensive fire detection coverage.

Advantages of Aspirating Smoke Detection Systems (ASD):

An ASD system is a highly sensitive system that can detect smoke particles at a very early stage of a fire, even before visible smoke is present. This early detection helps to alert building occupants and emergency responders quickly, increasing the chances of a successful evacuation and minimising property damage. They are the ideal solution for protecting data centres, museums and archives. ASD systems can cover large areas with a single unit, reducing the number of detectors needed and making the system more cost-effective. They are also fully customisable to meet your specific needs, including different levels of sensitivity and the ability to detect different types of smoke particles.

Disadvantages of Aspirating Smoke Detection Systems (ASD):

ASD systems require regular maintenance and testing to ensure proper operation. The network of pipes can become clogged over time, which can affect the performance of the system. They can also be more expensive than other types of smoke detectors and can be quite complex to install, requiring specialist knowledge and training. If not properly installed, ASD systems can be prone to false alarms, with the system being triggered by dust or other airborne particles, which can cause disruption to building occupants.

 

Radio-Controlled Fire Systems

A Radio Controlled Fire System is a fire alarm system that uses radio signals to communicate between the fire alarm control panel and the individual fire detection devices.

The system works by using a wireless radio network to transmit information between the control panel and the devices, such as smoke detectors and heat detectors, that are installed throughout the building. When a fire is detected, the device sends a signal to the control panel, which then activates the alarm system and alerts building occupants.

Advantages of Radio-Controlled Fire Systems

A radio-controlled fire system can be installed without the need for extensive cabling, which can reduce installation costs and minimise disruption to building occupants. The system can also be easily expanded or modified as needed, making it a flexible option for buildings that undergo changes or renovations over time.

Disadvantages of Radio-Controlled Fire Systems

One potential disadvantage of a radio-controlled fire system is that it may be more susceptible to interference from other radio signals or electromagnetic radiation in the environment, which can affect the system’s performance. Proper installation, testing, and maintenance are, therefore, essential to ensure the system operates reliably and effectively in the event of a fire.