How does it work?

A. Chemical action

There are certain reactions between atoms and parts of unstable molecules (radicals), which take place in rapid succession in the flame during combustion.

Unstable radicals try to become stable and undergo a number of reactions. A hydroxide (OH) is an unstable radical that also provides for the chain reaction of fire.

The potassium obtained from the discharge of the potassium compounds reacts during combustion with the free radicals of unstable hydroxides and forms potassium hydroxide (KOH), which is a very stable compound. In this phase the chain reaction of the free radicals stops and the flame goes out.

KOH reacts further in the presence of CO2 and forms K2CO3.

There are also other reactions that take place during the extinguishing that ensure that the end product is not harmful to humans, environment and matter.

B. Physical action

A certain amount of energy is needed for the chemical reactions to take place. The required amount of energy is supplied by the abundance of energy present in the flame.

Is it safe?

FirePro condensed aerosol is formed from commonly occurring elements.  It does not reduce oxygen within the protected area when discharged, nor does it have any harmful effects caused by coming in to contact with a fire.  There is a small pressure increase when the system is discharged but not enough to warrant pressure relief venting.  When it is discharged it is quite hot, but the design of the system will normally ensure that there is a safe distance between the FirePro generator and any risk.

What is the working life of a FirePro system?

FirePro systems are certified by both KIWA and UL for a 15 year working life.  At the end of this time the FirePro generators should be replaced.

All FirePro generators use the same solid block Potassium compound, in differing quantities. So all units have the same working life.

What are the benefits of FirePro over Gas Suppression Systems?

FirePro has many advantages over the more traditional high pressure gas suppression systems.


HFC-227ea are based on HFC technology and therefore have a high global warming potential of around 3000.  FirePro is a certified Green product with no global warming potential and no effect on the ozone layer.


FirePro is stored as a solid substance, so there is no pressure in the FirePro units.  Gas systems obviously have pressurised contents which requires specialist handling and delivery methods.


Changes to FirePro systems are easily incorporated.  Electrical cables are easier to install than steel pipe.  Adding a FirePro generator is quite simple, whereas gas systems will have to undergo complicated design calculations.


There is no need for over pressure venting with FirePro systems.


The allowable leakage area is much higher for FirePro systems than it is with gas systems.  This makes passing a room integrity test easier, both at the time of commissioning and every year thereafter.


The servicing and maintenance of FirePro systems is much easier and as the systems are fully electrical, can be done by the same engineer who is testing the fire detection system.


FirePro systems have a 15 year working life, whereas gas systems are required to be hydrostatically tested after 10 years.


The FirePro generators are normally mounted on the ceiling or at high level within the protected space, so there is no loss of valuable floor space.

Which types of Fire can FirePro be used on?

FirePro is certified for use on class EN-2 A, B, C & F superficial fires.  

The protected enclosure should be well sealed to contain the agent after discharge.

What if the protected room is not gas tight?

Unlike pressurised gas fire suppression systems, FirePro is tolerant of rooms that cannot be sealed that well.

Third party testing has concluded that provided the total equivalent leakage area of a room is less than 1% of the protected room volume, then using an extended discharge arrangement the room can be protected.

So in a room of 100m3 a hole of up to 1,000mm x 1,000mm is acceptable.

In rooms where the leakage area is less than 0.17% of the room volume then no additional measures are required.

This is because FirePro is a low density fire suppression agent and will stay suspended in the protected space for some considerable time after discharge.



Can it protect inside the risk?

Owing to the modular construction of FirePro systems and the variety of sizes of the FirePro generators, FirePro is ideal for installing directly inside the smallest of enclosures.

This method gives many benefits which improve fire safety and reduce overall costs.

Should the power to the protected space be removed?

It is always a good idea to shutdown the power to protected equipment.  This will normally help reduce the problem. So it is good fire engineering practice. 

Does the Air Conditioning need to be shutdown?

Yes it does.  Any forced air movement needs to be removed or shutdown.  This is in order to ensure that the FirePro agent discharges in to the protected space evenly.  Air conditioning units are normally fitted with large filters that will remove the agent form the air, stopping the FirePro from doing its job.

What needs to be done after a discharge?

Once it has been deemed safe to do so, the protected area should be ventilated to dissipate the airborne particles.  This can be done by simply opening the doors and windows to the protected space or, where this is not possible, a portable blower could be used.

Where the FirePro has been allowed to settle it can be picked up using a damp cloth.

Sensitive electronic components may need to be cleaned using an alcohol based cleaning solution.



We’re here to help

Call 08000 314333