safety
ATEX handsets F
irst responders in fi re and rescue services, as well as private business users adopting TETRA solutions for their operations – in off shore/onshore oil and gas,
petrochemical, food processing and other activities – may fi nd themselves frequently confronted by potentially explosive atmospheres in their workplace. T ese may be due to the presence of fl ammable gases, mists, vapours or combustible dusts. When air is mixed with these in the right proportions, all
that’s needed to create an explosion is an ignition source. Such a scenario might easily exist in the petrochemical industry, or where there are fi ne organic dusts such as grain fl our or wood, as well as in activities such as paint spraying at a local vehicle body repair shop. Reducing the risk of an explosion in such an environment
Fire in a chemical plant: the correct use of ATEX-
certifi ed electrical equipment,
including two-way radios, helps in avoiding accidents of this kind.
22
is best done by preventing dangerous substance release in the fi rst place, or eliminating the chance of an ignition source being added to the mix. Part of that process is ensuring that correct equipment is used wherever and whenever possible, and while ATEX requirements cover all industry sectors, equipment makers, etc, in the case of TETRA end users that means operating handsets which meet ATEX standards.
Regulations, directives Many countries have national law governing hazardous working environments. In the UK, for example, a duty of care is placed upon employers to eliminate or control explosive atmospheres in the workplace by the ‘Dangerous Substances
Many radio users face the hazards of potentially explosive atmospheres in their working environments. But with radio equipment certifi ed as intrinsically safe, they can communicate without creating accidental ignition. Tim Guest looks into ATEX equipment
and Explosive Atmospheres Regulations 2002’ (DSEAR). T ese defi ne an explosive atmosphere as a mixture of dangerous substances with air, under atmospheric conditions (20°C to 40°C and 0.8 to 1.1 bar of pressure), in the form of gases, vapours, mist or dust in which, when ignition occurs, combustion spreads rapidly to the entire unburned mixture. T ese regulations place the onus on any organization
whose staff may face such a scenario to ensure that they are appropriately equipped. In the European Union, two crucial European Directives,
known as ATEX (‘EXplosive ATmospheres’) directives, are aimed at regulating the control of those explosive atmospheres: Directive 99/92/EC (also known as ‘ATEX 137’ or the ‘ATEX Workplace Directive’) relating to minimum requirements for ensuring the health and safety of workers at risk from explosive atmospheres, and Directive 94/9/EC (also known as ‘ATEX 95’ or ‘the ATEX Equipment Directive’) concerning electrical equipment and protective systems intended for use in potentially explosive atmospheres. T ese help identify areas where explosive atmospheres
might exist, enabling employers or organizations to classify them into zones based on size, location, and likelihood of an explosive atmosphere occurring in that zone. Such a zone might be physically marked on site with ‘EX’ signage. Individual devices such as radios are marked with codes indicating the zones or hazards they are certifi ed for. T is is where several of today’s TETRA handset
manufacturers have stepped in to address the needs of those TETRA community radio users who face such hazards in
TE TRA TODAY Issue 7 2012
Photo: Motorola
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