What is a fire suppression system and how does it work?

A fire suppression system is an integral part of any fire protection infrastructure. ‘Fire suppression’ is a collective term for any engineering groups of units that are designed to put out a fire. This can be achieved by applying an extinguishing substance such as water, foam or chemical compounds. This article provides an overview of the purpose and functions of a fire suppression system, helping site teams and building owners create a reliable and fully-compliant fire protection strategy.

How does a fire suppression system work?

A fire suppression system will have built-in components to detect fires as early as possible. These components will first identify the presence of flames and smoke. The suppression system will then initiate an alarm, so the blaze can be subdued before it has the chance to spread.

When is a fire suppression system required?

Fire suppression systems should be installed in buildings where a sprinkler system may not be the most effective method of fire protection. These can include rooms which contain a large amount of electrical equipment, or perishable items that could be susceptible to water damage.

Although a fire suppression system is not legally required in the UK, property owners, be they commercial or residential, are responsible for carrying out fire risk assessments. This assessment, whether conducted internally or externally, may reveal the need for a fire suppression system. Further information can be found in our article on who exactly is responsible for fire safety legislation.

When identifying the best option for your specific needs, it’s advisable to know how both active and passive fire protection systems work in tandem to extinguish flames. This is vital for risk management, reducing the risk of structural damage as well as safeguarding a building’s occupants.

Methods of fire suppression

Broadly speaking, there are five main types of fire suppression system – all of which have unique properties and benefits based on the expect space in need of protection:

Gas systems

Gas systems store fire-suppressing liquids, which are pressurised with nitrogen. These liquids contain a chemical agent called FM200, which is quickly released to immediately suppress flames. Since these systems don’t use any water, they’re particularly beneficial for rooms with large amounts of electrical equipment such as switchboards or server rooms. The gas is initially condensed in liquid form and stored in compact cylinders, making these systems easy to transport and store.

Chemical foam systems for kitchens

There are chemical foam systems which are specifically designed for suppressing fires in kitchens. These systems work by quickly emitting a water-based chemical foam agent directly into a small, localised area. They are usually placed under the canopies of cookers and are activated by either a manual switch or a heat link (a link attached to a wire that breaks when exposed to heat, triggering the foam release valve).

Water mist systems

Water mist systems pose a viable fire suppression solution for spaces that cannot be exposed to large amounts of water. They work by producing droplets that are much smaller than conventional sprinkler systems. This creates a layer of steam which starves fires of oxygen, quickly reducing the temperature of the affected area. Since they use much less water than traditional sprinklers, they can to some extent be considered a more sustainable fire suppression method. We explore water mist systems in more detail in our article on emerging fire protection and suppression technologies.

Foam deluge systems

One of the biggest challenges in fire suppression is effectively safeguarding areas which contain flammable liquids. Foam deluge systems are the most effective means of controlling the spread of these environments. For this reason, they are commonly installed in refineries, aircraft hangers and industrial warehouses. A fire in these types of environments can accelerate tremendously quickly. Therefore, foam deluge systems are designed for the quick widespread application of suppressive materials.

Foam deluge systems use a mixture of foam and water to quickly control burning flammable liquids, cooling the surface area. The consistency of the foam causes a thick blanket to starve fires of oxygen and inhibit the release of flammable gases, effectively smothering the blaze. In this sense, they are not unlike conventional fire extinguishers.

Pneumatic heat detection tubes

Pneumatic head detection tubes are designed in a way that makes them very similar to fire extinguishers. Therefore, they can be considered the most compact and mobile fire suppression system. These tubes have two primary components: a pipe and a valve. The pipe is installed around the potential source of fire; when it reaches a certain temperature it emits a suppressive agent directly onto the flames via the valve.

Pneumatic heat detection tubes tackle fires in their beginning stages, located in small areas with little room for manoeuvre. Therefore, they are ideal for tackling fires in cabinets and cupboards, as well as boats and vehicles. This does mean, however, that they are unsuitable for suppressing large fires and therefore are not recommended for rooms or areas with a high ceiling.

We hope that this article has helped you gain a basic grounding in the purpose, function and requirements of a fire suppression system. Interested in finding out more about how fire suppression works in the context of an overall fire protection strategy? If so, take a look at a recent article where we explain the difference between fire protection, prevention and suppression.

CLM Fireproofing are the UK’s leading passive fire protection specialists. Our team of FIRAS-accredited experts offer a full suite of services, including fire compartmentation and intumescent fireproofing. For help developing a fully-compliant fire protection strategy of the highest possible quality, contact CLM Fireproofing today.