Posted By Chris Packham May I suggest that it will depend upon two factors. 1. The design of the heater. Is this such that the dust can actually gain access to the combustion zone? If not, then where is the risk? 2. Is there sufficient dust in the atmosphere to represent a risk of explosion or fire? If there is, then perhaps this should be examined from a different viewpoint, i.e. that of adequate control and containment/extraction. Chris

Posted By holmezy Ronan, In any wood / dusty environment where there is a source of combustion, there is a risk of explosion, however, providing the wood dust isnt light enough to be suspended in the air, and the suspended "cloud" isnt so dense that you have trouble seeing through it, then the risk of "explosion" is reduced, probably to a safe level.To be a true explosion, you need all the elements required for a fire, ie fuel, oxygen and ignition, plus you need containment (either fully or to a high degree). What has been known to happen is for thick wood dust to be disturbed in volume eg by allowing a plywood sheet to fall and "billow" the dust towards a heater. This has then caused a "mini" explosion (not really an explosion but at a fireball) which has subsequently caused another "billow" of dust and hence you get a chain reaction. The second expolsion (fireball) or resulting fire is usually for more destructive than the first. The main problem ( leaving aside inhalation, skin etc) with wood dust, is that it is capable of self combusting if left in a large pile, it has been known to smoulder and self generate heat for days until bursting into flames. Thats why good standards of housekeeping are necesary and also regualr maintenance of the LEV system as wood dust will collect and "pack" into any bends or corners. It then sits there, quietly smouldering until you turn on the LEV and introduce a nice breeze of oygen rich air, at which point it could burst into flames and be easily spread by the LEV system. The possibility of explosion is also increased within the LEV system due to its increased containment. If the filter system has a "shakedown" mode, then this could also be a potential explosive atmosphere, but would obviously need a source of combustion, but poor maintained mechanics have been known to produce sparks, then theres always static build up to condider!!! So long as you keep all the surfaces of your diesel heater free of dust, there should be little or no risk of fire or explosion. For more info re explosions etc, have a look at Dangerous Substances and Expolsives Atmosphere Regs, its a great night time read!! Soon be beer time AND Rugbys on tomorrow. C'Mon England (although I think the Welsh will do us)

Posted By peter gotch Hi Ronan. Most of what is produced will be flammable rather than explosive. Possibly explosive dust from sanding operations but unlikely to be enough suspended for reasons stated in previous message. However, need to keep any ledges etc clean in case of any reason for this to be disturbed, so resulting in explosive dust cloud. P