What Is an Automatic Fire Suppression System and How Does It Work?

When a fire can destroy valuable machinery in minutes, detecting and extinguishing it in seconds is vital. That’s where an automatic fire suppression system, which detects and suppresses fire without the need for manual intervention, comes in.

In this article, you’ll learn what an automatic fire suppression system is, the different detection methods available and the kinds of environments they protect.

What is an automatic fire suppression system?

An automatic fire suppression system is a safety system that detects and suppresses fire without the need for manual intervention. Systems can be designed for specific vehicles, machinery and other static assets, and retrofitted to protect engine bays, hydraulic systems and other high fire risk areas.

Unlike a portable fire extinguisher, which relies on an operator being present and trained to use it, these systems operate independently around the clock, regardless of whether the machine is in use or not.

This distinction makes an enormous difference in real-world scenarios where incredibly valuable equipment is at risk. In many cases, whether it’s on a farm or on the railway, by the time an operator notices smoke and reaches for an extinguisher, it’s already too late.

How does an automatic fire suppression system work?

While individual configurations vary depending on the asset they protect, all automatic fire suppression systems follow the same fundamental process:

• Detection. Identifying the presence of heat or fire at the point of ignition.
• Activation. Triggering the release of a suppression agent automatically, without operator input.
• Suppression. Deploying the agent directly or indirectly (for maximum coverage) at the fire source to suppress it and prevent reignition.

Additional safety features, such as in-cab monitoring fascias, automatic engine shutdown and battery isolation, can be integrated to protect the operator and asset when the system activates.

Pneumatic vs electronic linear: What’s the best detection method?

Automatic fire suppression systems typically use one of two detection methods: pneumatic detection and electronic linear detection (also known as Linear Heat Detection, or LHD). Understanding the difference between them will help you make the right choice.

Pneumatic detection

Pneumatic detection uses a pressurised tube, which runs throughout the asset's hazardous areas.

When the tube is exposed to heat or flame exceeding 180°C, it ruptures at the exact point of ignition. This causes an instantaneous pressure drop, which opens the cylinder valve and discharges the suppression agent in seconds. Because the tubing physically contacts the heat source, detection is direct and precise.

Here are the key advantages of pneumatic detection:

• No electrical power required. The system is entirely self-contained and operates independently of the machine's electrical system.
• Ultra-fast response. It typically detects and activates within seconds of ignition.
• Genuine 24/7 protection. The system remains active whether the machine is running or parked, day or night.
• Standalone reliability. If the machine's electrical system fails, the suppression system continues to function.

Electronic linear detection (LHD)

Electronic linear detection uses a heat-sensitive cable rather than pressurised tubing. In the event of a fire, the cable's insulation melts and the inner conductors make contact to create an electrical short circuit. A control module detects the change in resistance, which signals the suppression cylinder to activate.

However, for vehicle and mobile plant protection, it carries several drawbacks:

• Slower detection. LHD systems typically take 20 seconds or more to detect and respond to a fire, compared to the much quicker activation time of pneumatic systems.
• Power dependency. LHD systems require an electrical power supply to function. If the machine's battery is isolated or the electrical system fails, the suppression system is rendered inactive.

At Fireward, we supply both pneumatic and LHD systems and recommend the right solution for each application. However, for the vast majority of vehicle and mobile plant installations, pneumatic detection is our preferred solution.

What agents do automatic fire suppression systems use?

There are three major types of agents that automatic fire suppression systems can use: single-agent, dual-agent and clean-agent.

Single-agent fire suppression systems use dry powder to rapidly smother flames and cut off the oxygen supply. Dry powder is the single most effective agent for rapid fire knockdown. Its particle size creates a large suppression area and even reaches hidden flames.

Dual-agent systems combine a dry-powder cylinder with a wet-chemical cylinder into a single integrated system. The two agents work in tandem. The dry powder discharges first, rapidly knocking down the fire and cutting the oxygen supply. The wet chemical follows, delivering a prolonged cooling effect on hot surfaces that could reignite the fire.

Clean-agent systems use specially formulated gaseous agents rather than powder or chemical. Fireward's clean agent systems use Reacton™ 1230 fluorinated ketone and FM-200™ (HFC-227ea). Both agents are stored as liquids and discharged as gases, suppressing fires either by absorbing heat from the flame or by interrupting the combustion chain reaction.

Unlike single- and dual-agent systems, clean-agent systems leave no residue. This makes them essential in protecting sensitive electrical components where the suppression agent itself could cause as much damage as the fire, such as electrical panels, control systems and CNC machinery.

Choose Fireward for your automatic fire suppression system

Fireward is the UK's leading provider of automatic fire suppression systems for vehicles, mobile plant, machinery and other specialist assets. We have installed systems on more than 10,000 assets across the UK, working with leading manufacturers and operators in demolition, waste and recycling, agriculture, construction, rail and manufacturing.

When you choose Fireward, you benefit from:

• 24/7 autonomous protection. Our pneumatic systems operate without power or driver intervention, every hour of every day
• Ultra-fast detection and activation. Our systems respond in seconds, making them among the fastest-acting systems on the market.
• Nationwide installation and servicing. Our field engineers are strategically located across the UK, installing and servicing systems with minimal disruption to operations.
• Three-year parts and labour warranty. All systems come with a three-year warranty as standard with direct clean agent systems being 5 years. All systems are backed by a six to twelve month servicing programme (depending on application and asset) to keep your system performing exactly as designed.
• Full accreditation. Our systems are third-party certified to P-Mark SPCR183, P-Mark SPCR199 and AS-5062:2016, with additional clean agent accreditations to UL 2166 and LPS 1666.

To find out more or to request a free quote, get in touch with our team today. Call us on 0800 151 0249, email sales@fireward.co.uk or send us a message.