Does my industrial hoover need to be ATEX certified?

This is probably one of the least understood questions in dust management and there are two parts to it which need addressing separately.

Firstly, we need to understand explosive atmospheres.

An explosive atmosphere is any environment where flammable gas or airborne combustible dust does, is likely to or could, mix with sufficient oxygen in the air so as to become ignitable. At this point, to introduce any source of ignition produces effects which can be calamitous in cataclysmic proportions. The more closely contained the environment, the more violent the explosion can be.

For officially zoned hazardous areas, use of ATEX certified equipment is a legal requirement. Different hazard zone ratings relate to the scale of risk and equipment must be selected according to its specific certification category.

So, that is clear and leaves us in no doubt but...? What about areas that are not zoned? How do I know if areas are zoned or should be zoned? What does ATEX mean and what's it all about?

ATEX refers to the European directives that define explosive atmospheres and the standards required for the safety of workers and equipment operating within them. It is a name coined from the French "atmospheres explosibles".

ATEX certification is awarded to equipment that has been tested and proven to be intrinsically safe, which means that it is incapable of itself becoming a source of ignition and therefore fit for use in explosive atmospheres. Such equipment qualifies to carry the distinctive "Ex" mark signifying ATEX approval.

In principle, ATEX has become a universal standard?and most countries have legislation in accordance with or based upon the ATEX directives.

For the UK, it is the recently introduced UKEX certification which follows the standards set out in what has become known as DSEAR, The Dangerous Substances and Explosive Atmospheres Regulations 2002, putting the responsibility for controlling the risk of explosive atmospheres at work fairly and squarely on employers.

Secondly, we need to understand how to manage the risk.

It is easy to give ourselves a false sense of security in trying to control the risk as we can actually be simply transferring it rather than eliminating it. For example, we can extract dust from a process to avoid a concentration build up in the factory and in doing so, create a potential hazardous zone within the extraction equipment itself.?

Consider a combustible dust being drawn into an extraction unit in oxygenated air. The friction of the dust travelling at high velocity in the hoses and pipework can cause a build up of static. When the dust reaches the container, it doesn't immediately settle into a dust mass but remains airborne for some time, during which time it is very likely it will pass through its ignition point which, if coincidental with a discharge of static producing a spark, explosion can and will occur.

So, in conclusion, to minimise the chances of this scenario, using an ATEX certified dust extractor, vacuum cleaner or "hoover" (as you call it) is the safest option, even when the working environment itself is not classified as a hazardous zone.

But do remember that not all dust is combustible. First and foremost, do your risk assessments, define the hazards and take care.

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