Hazardous Area Classification
It is a requirement under the UK’s Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR), which implement the safety aspects of the European Chemical Agents Directive (CAD) and Explosive Atmospheres (Protection of Workers) Directive, otherwise known as ATEX 137 within the EEC, to ensure that Hazardous area classification is carried out.
Establishing Hazardous Area Zones
The process of classifying an installation or plant into Zones where the probability of flammable atmospheres/hazardous areas exists, and is assessed, is known as Area Classification.
This Area Classification process is carried out in accordance with prevailing standards appropriate to the location of the plant, and/or existing legislation - for example, the current European Normative for Area Classification is BS/EN 60079-10 and the relevant IEC standard. Although there are other codes that may be used such as those issued by Institute of Gas Engineers (IGE) and Institute of Petroleum (IP – now the Energy Institute), where they are more applicable to the industry.
Under area classification rules the personnel, carrying out the classification exercise must take into account, but not limited to, the sources of release, grade or frequency of release, and ventilation in determining the zone and its extent and place the areas into the different types of zones including non-hazardous.
Classification |
Criteria for zone |
ATEX Marking |
IEC EPL |
|
Zone 0 |
Flammable material is present continuously or for long periods or frequently |
G |
Category 1 Equipment |
Ga |
Zone 20 |
D |
Da |
||
Zone 1 |
Flammable material is likely to occur in normal operation occasionally |
G |
Category 2 Equipment |
Gb |
Zone 21 |
D |
Db |
||
Zone 2 |
Flammable material is not likely to occur in normal operation but, if it does occur persists for a short period only |
G |
Category 3 Equipment |
Gc |
Zone 22 |
D |
Dc |
||
G = Gas, vapour or mist D = dust |
This is a complex area and FES applies the relevant standards and codes of practice or modelling to ensure that zones are kept to a minimum. We also takes into account business impact and work closely with our clients to ensure minimum disruption.