ATEX & DSEAR regulations – what they are and how do they work

Guidance in hazardous areas: ATEX and DSEAR

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In many industries, employees face several hazards such as flammable gases, dangers of confined space entry, release of toxic gases and exposure to aggressive chemicals. In addition, there’s direct contact with corrosive substances such as chlorine compounds, sulfuric acid, ammonia and potassium hydroxide. There are several directives and regulations that offer guidance through this dangerous field – most importantly ATEX and DSEAR regulations.

ATEX directives

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The ATEX directives describe what equipment and work space is allowed in environments with an explosive atmosphere. The name ATEX derives from the French title of the 94/9/EC directive: Appareils destinés à être utilisés en ATmosphères EXplosives.

ATEX zones for gases and vapours

Zone 0
A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is present continuously, or for long periods or frequently.

Zone 1
A place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally.

Zone 2
A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

ATEX zones for dust

Zone 20
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently.

Zone 21
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally.

Zone 22
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

ATEX at a glance

Explosion protection and gas detection: Ex-marking and meaning

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DSEAR regulations

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DSEAR stands for Dangerous Substances and Explosive Atmospheres Regulations from 2002. Dangerous substances can put peoples' safety at risk – from fire, explosion and corrosion of metal. DSEAR puts regulations in place asking that employers and self-employed protect people from these risks to their safety in the workplace. Members of the public who may be put at risk by work activity must also be protected.

What are dangerous substances?

In this case, dangerous substances refer to any substances present at work that could, if not properly controlled, cause harm to people as a result of a fire or explosion or corrosion of metal. They can be found in nearly all workplaces and include such things as solvents, paints, varnishes, flammable gases (such as liquid petroleum gas (LPG)), dusts from machining and sanding operations, dusts from foods, pressurised gases and substances corrosive to metal.

What does DSEAR require?

Employers must:

find out what dangerous substances are in their workplace and what the risks are
put control measures in place to either remove those risks or, where this is not possible, control them
put controls in place to reduce the effects of any incidents involving dangerous substances
prepare plans and procedures to deal with accidents, incidents and emergencies involving dangerous substances
make sure employees are properly informed about and trained to control or deal with the risks from the dangerous substances
identify and classify areas of the workplace where explosive atmospheres may occur and avoid ignition sources (from unprotected equipment, for example) in those areas