Electrical arcing from battery-powered tools causes Scrap Yard Fire
I wrote a few weeks ago about a scrap yard fire in London which resulted in a man being hospitalised, when seven tonnes of scrap metal, including vehicles, caught alight. The investigation by the London Fire Brigade has now concluded that electrical arcing from a battery-powered tool had ignited petrol vapour from a nearby open petrol can. There are always lessons to learn from incidents like these, but this fire in particular stands out as an interesting example with some valuable takeaways for the wider industry, including how to handle and store flammable liquids and the safe use of cordless tooling. Let's deal with petrol first.
There should never be open petrol canisters near any form of hot or electrical work, and so these occurrences usually stem from bad practice, inadequate training or a lack of supervision. Petrol fires are always serious and often result in fatal or major injuries, as well as major property damage.
Common ignition sources include:
smoking and lighted matches;
welding and cutting equipment;
all types of electrical equipment, unless these are designed as suitable for use in a flammable atmosphere (this includes cordless tools).
As well as the sources listed above, the action of draining petrol into a container can generate static electricity which, if not controlled, can result in a spark. When thinking about sources of ignition, remember that petrol vapour does not disperse easily but can spread over a wide area. It tends to sink to a low level and may collect in tanks, cavities, drains, pits or areas where there is little air movement.
It is important to drain any petrol into a suitable container large enough to hold the contents of the fuel tank, with a cap that can be securely closed. Always use a fuel retriever for draining tanks and lines, don't mix petrol and diesel, and don't mix recovered fuel with waste oil. The use of a proprietary fuel retriever such as those integrated into depollution equipment solves most of the hazards of fuel removal by:
providing a suitable container;
providing the means to eliminate static electricity;
and capturing any vapour displaced.
The total capacity of containers must be between 10% and 15% more than the volume of liquid stored in it, allowing space for the petrol to expand.
Battery-Operated Cordless Tooling
Electrical equipment including cordless tooling, intended for use in potentially explosive atmospheres must be ATEX certified. If it isn't then it MUST NOT be used within DSEAR zoned areas. Manufacturers or suppliers of such equipment ensure their products meet essential health and safety requirements and undergo appropriate conformity procedures. This involves testing and certification by a ‘third-party’ certification body and once certified, the equipment is marked by the ‘EX’ symbol to identify it as ATEX certified.
The vast majority of ATEX certified tooling is air powered, however there are a few suppliers of ATEX certified hydraulic and battery operated tools. Either way, any tooling (powered or unpowered) being used in a DSEAR zone must be certified, non-sparking and most importantly, selected and approved by the employer as appropriate for the task and the environment. It's likely that in the case of this scrap yard fire, non-certified cordless tooling was used and as such, a spark from either the tools normal operation, a short circuit, or the process by which the tool's battery is attached/detached during charging, has caused the latent petrol vapour to ignite. Whatever the precise circumstances it is acceptable to say that it was all easily avoidable. Investing in the right tools for the job, and the selection and proper use of appropriate storage containers for flammable liquids are essential.
Remember, having all the correct equipment can only take you so far. The most effective way to combat scenarios like these is to also provide your employees with regular awareness training to ensure they can keep themselves and your business safe from the risk of fire.