30 SEPTEMBER 2013

Safe Cleaning – Be Mindful Of Standards

A huge legal responsibility lies on those responsible for cleaning up dusts and other materials within the oil and gas industry. It is essential that it is done without affecting the health and safety of workers. The legal situation is complex for employers and cleaning companies and this article is aimed at providing a better understanding of the legal requirements and the solutions available.

 

Modern industry deals with an ever-increasing variety of materials in a variety of working conditions.  Some of these materials in dust form are known to be hazardous to health; other materials may not be thought of as a health hazard but could, in the right circumstances, prove lethal if cleaned up using the wrong equipment. Some of the cleaning machines may have to work in hazardous areas caused by the presence of flammable vapours or gases and so should be constructed accordingly to the relevant standards.

 

Why could my vacuum cleaner explode?

 

If the material being collected is combustible and drawn into a vacuum cleaner then it is mixed with large amounts of air which form a cloud of dust or flammable vapours inside the machine.  All that is then required to produce an explosion is an ignition source.  Vacuum cleaners produce static electricity as the dust passes through the machine. Conventional vacuum cleaner motors also produce sparks from carbon brushes. Therefore the combination of all 3 essential elements required for an explosion can be present!

 

Fortunately these risks have been recognised and technical solutions found which remove the risk of ignition. Machines for combustible dusts are constructed in such a way that static electricity is safely routed to earth and the motors used do not create sparks. Additional constructional standards apply to machines that are required to work in atmospheres which are hazardous due to the presence of flammable gases or vapours.

 

The employer has legal duties under the ATEX 137 Directive to conduct a risk analysis on his processes (which include cleaning!) and to then select ATEX approved equipment intended for use in high risk areas. The employer also has duties under the Dangerous Substances and Explosive Atmospheres Regulations 2002 that specifically include implementing control measures and providing equipment which reduce the quantity of dangerous dusts and prevent explosive atmospheres. Manufacturers of safety vacuums like Nilfisk-CFM, therefore, have produced Safety Vacuum Cleaners that are specifically designed for the collection of combustible dusts. Only special Notified Bodies to which the machines are submitted for testing give the ATEX certification for equipment in potentially explosive atmospheres.  The ATEX approval will be specific to the category of equipment and nature of the risk (combustible gas, vapour or dust etc) considering the particular hazardous zone etc. (e.g. zone 21, zone 22, zone 1 or zone 2.)

 

Hazardous places are classified in terms of zones on the basis of the frequency and duration of the occurrence of an explosive atmosphere. Zone classifications are as below:

 

For gases, vapours and mists the zone classifications are:

 

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

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Zone 1 - A place in which an explosive atmosphere consisting of a mixture with air of dangerous 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 dangerous 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.

 

For dusts the zone classifications are:

 

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 frequent long periods.

 

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.

 

Machines are available to collect hazardous materials yet work safely within either non hazardous or certain hazardous ATEX zoned areas caused by the presence of flammable gases, vapours or combustible dusts.

 

Nilfisk-CFM is part of the Nilfisk-Advance group and has been manufacturing specialist commercial cleaning equipment for over 100 years. Specialist advice, surveys and free demonstrations can be arranged by contacting 01284 763163 www.nilfisk-cfm.co.uk