CLASSIFICATION OF HAZARDOUS AREAS ACCORDING TO IEC 60079-10
Hazardous area classification is a structured means of assessing risks and instigating appropriate preventative measures to prevent ignition of flammable mixtures. Codes of practice have been established for the classification of potential hazards and similar codes deal with the selection, installation and maintenance of suitable equipment to protect against these hazards. The codes of practice may be locally, nationally or internationally recognised documents.
These documents will list the generic methods of protection which may be used to achieve an acceptable level of safety.
The process of classifying an installation or plant into Zones whereby the probability of flammable atmospheres (or hazardous areas) arising is assessed is known as Area Classification. IEC 60079-10 is the prevailing International Standard which addresses this subject.
Hazardous Area Classification Plan
A set of documents providing information on the hazardous areas of the plant is created. As a minimum this shall comprise of :-
- Area Classification Drawings,
- Details of the Flammable Substances being stored, handled, or processed,
- Details of the Sources of Release,
- Information on the Areas of Risks, and in the case of enclosed spaces,
- Information relating to the ventilation and air conditioning design, which affect the classification and extent of hazardous locations.
Hazardous Area Classification Drawings
A set of drawings showing to scale the complete layout of the facility, marking the extensions of the hazardous locations defined based on the specific data associated with the flammable substances, sources of release and areas of risk for all elevations.
Standard Symbols for Identification of IEC Hazardous / Classified Areas
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ZONE 0 | NON-HAZARDOUS AREA, PROVIDED THAT IT IS MAINTAINED WITH A POSITIVE PRESSURE |
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ZONE 1 | AREA WHOSE CLASSIFICATION IS ONLY VALID WITH THE USE OF NEGATIVE PRESSURISATION |
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ZONE 2 |
