Electrical Systems

Explosive environments

If machinery or equipment is to be used in an explosive environment, the design engineer and local fire marshall must use North American HAZ-LOC standards to decide what level of protection is needed.

By Charles Skinner

If machinery or equipment is to be used in an explosive environment, the design engineer and local fire marshall must use North American HAZ-LOC standards to decide what level of protection is needed.

HAZ-LOC requirements divide products into three explosive categories that range from “very likely” to “likely” to “less likely.” The explosive environments within the plant are then broken down into zones that represent the intended areas of use for equipment. Products approved for use in the most dangerous zone can be used in less dangerous zones, but products approved only for lower danger zones aren’t compatible for more dangerous zones.

Obviously, electrical power can be the spark that ignites an explosion, and this is why a review of a plant’s electrical distribution system is part of any HAZ-LOC review and certification.

Once a HAZ-LOC review is completed and appropriate levels of protection are determined, the requirements of NFPA 70 and the Canadian Electrical Code can be followed to ensure a safe installation.

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