Regulations 169 and 170
1. Places where explosive atmosphere may occur:
(a) A place in which an explosive atmosphere may occur in such quantities as to require special precautions to protect the health and safety of the workers concerned is deemed to be hazardous within the meaning of Part 8 of these Regulations.
(b) A place in which an explosive atmosphere is not expected to occur in such quantities as to require special precaution is deemed to be non-hazardous within the meaning of Part 8 of these Regulations.
Flammable or combustible substances are considered as materials, which may form an explosive atmosphere unless an investigation of their properties has shown that in mixtures with air they are incapable of independently propagating an explosion.
2. Classification of hazardous places
Hazardous places are classified in terms of zones on the basis of the frequency and duration of the occurrence of an explosive atmosphere.
The extent of the measures to be taken in accordance with P
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