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We often get asked here at S2 Fire Solutions, which fire alarm system should I have? What kind of fire alarm system would be suited to my company and what is the difference between the various types of fire alarm systems?  So to help shed some light on this, we would like to explain the 3 most common types of alarms out there and the benefits and purpose of these.

All fire systems operate on the same principle, if a detector detects smoke or heat or someone operates a break glass unit (call point) then alarm sounders and VADs  (visual alarm devices) operate to warn others in the building that there may be a fire and to evacuate.

The type of system you require may depend on the size and condition of the site. Our team can find the right system for your site; whether it requires specialist equipment such as intrinsically safe or explosion proof, minimal disruption as within a listed building or is a multi-panel networked system. No matter how big or small, we have experience of working with an option to suit you. For example:

Air sampling

In addition to detecting fires in the very early stage, air sampling can also be used for gas detection. This system is most beneficial in sites such as large warehouses, cold stores and areas where early detection of smoke is required like server rooms. The disadvantages of this system can be best explained using the following example. A warehouse uses a large air sampling system that contains multiple detection pipes with many vacuum holes that are linked to one detector. That detector will only show you which pipe picks up smoke not an exact position such as a particular vacuum hole.

Linear heat detection

This detector is not susceptible to dirty or damp environmental conditions. This cable is ideal in underground sites such as car parks. Another string to the linear heat detection’s bow is it can be used to protect cable ducts and trays by sharing the same containment as other services in this application the linear heat cable would react to overheating of adjacent cables lading to early detection of potentially dangerous scenarios. This cable does not react to smoke particles so it is not suitable for covering escape routes such as corridors and stairwells. In addition to this, heat would need to be generated by a potential fire to activate the fire alarm.

Fibre networking

Using this type of infrastructure to network a fire alarm system can potentially mean that panels can be located up to 20 kilometres apart. Fibre optic cables are immune to cross talk from other cables and induced interference. This system is more appropriate for multi-building sits such as educational campuses. In some instances, fibre can be used to connect panels using an existing fibre infrastructure. This system can incur high costs due to the equipment required for its operation such as media converters. This system typically is used for multi-panel networks on larger sites.

Intrinsically safe

By limiting the current of the fire alarm field devices such as detectors, this system can be used in explosive atmospheres such as petroleum stores. These devices tend to integrate into a larger system complimenting the main building fire alarm. This system is costly and is usually used for specific high-risk areas. Explosion proof – If an intrinsically safe system prevents an explosion, an explosion proof system creates an extra layer of equipment protection after an explosion has occurred. These devices are typically used in the most volatile areas such as chemical production plants. These heavy weight items are expensive and bulky meaning they are likely to stand out in rooms that aim to be aesthetically pleasing.

Radio systems

These operate using radio communications to a control panel. Often these can be combined with addressable or conventional systems to make a hybrid system. This may include sites with closely linked satellite buildings such a remote boiler room for a school. Radio systems are commonly used for sites that require minimal cabling such as heritage buildings. Radio communicators have a limited broadcast range. However, we can create a system using multiple communicators called a mesh. This essentially allows a signal to be broadcast from one communicator to the other before reaching the panel. This system does require regular replacement of integral batteries and the signal may be interrupted if you alter the building in any way such as adding partitions in rooms.


The most basic of fire alarm systems often used for small commercial premises such as shops. This system uses a low cost field devices and control panel to signal fire conditions. The fire alarm panel will accept zoned inputs for detector and call points, interpret these and then switch on sounder circuits in the event of an activation. This system would only display in which zone an activation has occurred not the specific point of detection. In a conventional system, inputs are wired on separate circuits to output devices.


This system is very similar in architecture to conventional systems. The main difference is the inputs and outputs to the system can be wired on the same cables. The advantages are you use less cable thus your installation costs are cheaper. Again this system is most suitable for smaller premises and is the preferable choice for small businesses because it can offer the same level of protection at a reduced cost.


This system is the mainstay of the modern fire alarm industry. The system uses intelligent devices (both input and output) fitted to either single or multiple detection loops. These systems are often networked to provide a complete solution to the fire alarm demands of a larger site. Because of the technology involved with field devices, this system is more costly but this would give you an individual point of location for any activation.

Wide area sounders

These are often used for large industrial or military installations. These can give a site wide warning of incidents to a large number of people both internally and externally very easily. These sounders are phenomenally loud and should only be used externally. These are sometimes knows as ‘Tsunami Sounders’.


A wireless fire alarm system is an addressable fire alarm system that uses radio transmission to communicate between devices such as the detectors, call points, sounders and control panels.