F for Fire
This month we focus on fire which, in addition to having a devastating impact on a hobby or business, can also threaten the life of anybody working or present in the area. Many fires occur after workshops have been vacated at the end of a work session, it therefore makes sense to stop machines a few minutes before leaving the workshop and switch off the electricity supply to the machines.
Sweep debris from machines, paying particular attention to motors and parts liable to get hot. Clean up shavings and debris - beware of using vacuum cleaners just before exiting the workshop - the increased airflow through smouldering shavings may establish a flame - which you then leave to develop into an inferno. If possible store shavings and dust in a separate building away from the workshop, better still aim to minimise the volume of waste you keep on your premises.
An explosion is a rapidly burning fire. There are two primary causes of explosion in a woodworking workshop environment. A dust explosion occurs when there is sufficient dust burden in the air to sustain a fire and the dust is ignited. Because of the fine nature of the dust and the abundance of air (and oxygen) around it the dust burns so fast that it creates an explosion. An initial dust explosion frequently disturbs accumulated dust which then ignites and results in a more severe secondary explosion. (It is now believed that the liner Lusitania sank as the result of a massive secondary explosion of coal dust created after a single torpedo exploded on the starboard side of the vessel).
A vapour explosion occurs when vapours from a volatile compound are allowed to collect and are then ignited. In the workshop these can be from adhesives, stains and colouring chemicals, solvents, finishes and coating materials. (The Buncefield oil distribution depot explosion was such an event).
The various types of heating available for use in a workshop have different fire and explosion risks. Any heating which provides a source of ignition to the atmosphere in the workshop should be avoided. Even switching an electrical device can create a spark which is sufficient to initiate an explosion.
Think of how you would fight a fire in your workshop. What fire extinguishers are there and for what type of fire are they suitable? Beware of using water on electrical equipment.
Keep cooling fins on motors clean to prevent overheating. Dust reduces the cooling allowing the motor to heat up and then provides a fuel as temperatures continue to rise.
Fire requires 3 things to get established, fuel, oxygen and a source of ignition. Remove any one of these from the Triangle of Combustion to minimise the risk from fire.
LEARNING POINT - DON'T give fire a chance to take hold! Trevor Branton