What is the Risk?
Fire is a constant risk, whether at home or in the work place. In the work place the risk can be much higher as there are often processes, jobs and applications that create ignition sources and often large amounts of highly flammable materials around, not to mention high value equipment and property and the most important thing – people’s lives.
Extracting dust and fumes from applications that cut and mark materials cannot only produce ignition sources (sparks, heated/ smouldering embers) but also potential fuel sources (laser engraving of wood) and an oxygen source (the extracted air stream).
An example of this is extracting from laser cutters and engravers. If we take a company laser cutting wood or metal for example. When a laser CNC cuts something like stainless steel or aluminium the high-power density of the laser results in extremely fast heating, metaling and partial or complete vaporization of the metal. Usually then a gas like pure oxygen or nitrogen is used to blow the molten metal out of the head – or Kerf as it is usually referred to.
Usually this molten metal – mild steel melts at around 1300oC – will cool rapidly. As the pieces of metal are so small they bleed off heat very fast. But even rapidly cooling metal fragments take some time to cool down from 1300oC and extremely hot metal dust and swarf can be drawn into the extraction process.
Dry dust filters are themselves dry and can ignite.
So, now an incredibly hot piece of metal is drawn into a compact airstream (think a burning ember flaring in the wind) and dumped into a dry filter – a potential fuel source – with yet more air being drawn over it, just like fanning the flames of a bonfire to get it to ignite. The result can be the filters in the extraction system itself igniting. Extraction systems are often slightly positively pressurised containers and if the filters ignite the pressure in the extractor can build and need releasing, potentially resulting in a degree of an explosion or at the least flaming materials spilling out of the container.
Either way, you now have a flaming box with plenty of fuel in the middle of a work area, surrounded by many other combustible and potentially explosive materials and people.
Controlling the Risk
Stopping this scenario can be very difficult. Sometimes it is not a case of preventing the fire in the first place as the chance of ignition may be inevitable. For example, a laser cutter working 6 – 8 hours a day 5 days a week will produce a lot of molten metal.
So, then the aim is to control the fire when it inevitably happens.
The new BOFA FireBOX GA and FireBOX MA are revolutionary new inline secondary filter systems designed to not only contain a fire but extinguish it before it spreads, removing the danger directly at the source, protecting the main extraction system, the work place and most importantly the people in the work place.
The BOFA FireBOX MA and GA models include an inbuilt dust pre-filter, aimed at adding further protection to the main extraction filter unit and both units have a two-tiered control system to prevent a fire. The internal sensors are sensitive to temperatures. The user can set the base ambient temperature level and if the FireBOX internal temperature increases rapidly by more than 10oC then the BOFA FireBOX will shut down the extraction system by automatically activate its shut of values to cut the air flow and kill the power to the main extraction unit.
On top of the BOFA FireBOX MA and BOFA FireBOX GA is an easy to see warning light that will begin to flash when this happens, letting the operators know there is a problem. If shutting down the system doesn’t stop the fire and the internal temperature continues to rise rapidly by another 10oC than the FireBOX MA and GA have an inbuilt fire extinguisher which will simply flood the internal chamber with foam to completely put the fire out.
Also, the handy signal light on top will flash red to let operators know there is a fire and the system has filled with extinguisher. Once it is safe to do so, wheel the FireBOX outside and wait for the fire brigade.
PLEASE BE AWARE: Even with inbuilt fire control in FireBOX MA and FireBOX GA internal fire procedures should be adhered to. The companies internal fire safety procedures should be followed at all times and the fire brigade should be called immediately if required.
