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Understanding ATEX

Edited by the Engineeringtalk editorial team Mar 7, 2005

Have safety manufacturers and end-users really come to terms with the regulations introduced in the latest ATEX Directive?

Have safety manufacturers and end-users really come to terms with the regulations introduced in the latest ATEX Directive? Certainly, the manufacturers of machines and components used in potentially explosive environments should to have a better understanding of the requirements of the ATEX 95 Directive and what is involved to achieve compliance.

Responsible companies will have started with an inspection of their machines or processes to ensure they comply with the latest directive and, if there was any doubt, would have employed a third party notified body to explain the processes required to achieve compliance.

Where existing machinery or processes had products fitted before 1st July 2003, reclassification of the zoned areas in and around the machine should have been carried out by a competent assessment organisation and needs to be completed by 1st July 2006.

It should also be noted that companies operating in areas such as process automation and material handling where the machines are used, have an additional responsibility.

Under the Worker Protection Directive 99/92/EC or ATEX 137 they are now responsible for protecting workers by ensuring that they are fully trained and knowledgeable about the machinery they operate and environment in which they work.

Manufacturers of safety equipment used in potentially explosive atmospheres are allowed to self-certify components such as safety switches to equipment category 3G or 3D and issue a CE declaration of conformity.

Obviously they must be able to validate the test requirement used and, if the proper equipment isn't available, must use the services of an independent test laboratory.

This self-certification facility has certainly benefited manufacturers such as Schmersal, as we have been able to bring ATEX approved products quickly to market rather than having to wait long periods for prototype test certification by a third party approval body.

Although these are important new developments, what is more important is that, for the first time, the ATEX Directive uniformly governs explosion protection against dust.

This is significant because experts estimate that there are far more explosions involving dust than gas and, in these environments, one spark is enough to cause serious damage.

This is an issue that should concern many safety engineers because all flammable substances are capable of reacting explosively when they are finely spread like a dust cloud in the atmosphere.

This applies to wood and plastics, food ingredients such as coffee and flour, and even for combustible metal dusts such as aluminium and magnesium, which are employed more and more in the automotive industry for weight-saving.

Manufacturers of machines used in areas endangered by dust explosions must identify the zone and choose components that are ATEX compliant for zones 20 and 21.

As for manufacturers of safety products, as already mentioned a "notified body" must certify both the products and the production facility.

This raises concerns that some safety component manufacturers may not fully understand the separate requirements for gas and dust environments.

Safety specifiers should therefore ensure that components specified for potentially explosive atmospheres actually comply with the Directive 94/9/EC (ATEX), and that the appropriate certificate of conformity has been issued for every device.