Undoubtedly, the world is getting smaller. With each passing year more and more opportunities become available both at home and abroad. In order for Canadian companies to participate and to prosper it became necessary to consider global approvals for electrical equipment for use in hazardous locations.
Traditionally, North American regulations have been based around the Class/Division system while European authorities followed a multi-tiered Zone system. The adoption of the Zone system in North America brought substantial change to the hazardous location industry. While the purpose of each system is to the same end, they are fundamentally different in design. There are certain differences between the Canadian Electrical Code and the National Electrical Code when it comes to Zone approved equipment. The material contained herein is in reference to the Canadian Electrical Code. Although the Class/Division system and the Zone system are similar in many ways there are some very distinct differences. The fundamentals of hazardous locations apply to both systems but the definition of a hazardous environment and construction of equipment differs.
One factor that is occasionally overlooked is that the fundamental laws of chemistry apply to hazardous locations. The Fire Triangle is commonly referenced since it defines the requirements for a fire to exist. According to the principles of the Fire Triangle a fire can only exist if all three sides of the triangle are present and in the proper quantities.
Traditionally, North American regulations have been based around the Class/Division system while European authorities followed a multi-tiered Zone system. The adoption of the Zone system in North America brought substantial change to the hazardous location industry. While the purpose of each system is to the same end, they are fundamentally different in design. There are certain differences between the Canadian Electrical Code and the National Electrical Code when it comes to Zone approved equipment. The material contained herein is in reference to the Canadian Electrical Code. Although the Class/Division system and the Zone system are similar in many ways there are some very distinct differences. The fundamentals of hazardous locations apply to both systems but the definition of a hazardous environment and construction of equipment differs.
One factor that is occasionally overlooked is that the fundamental laws of chemistry apply to hazardous locations. The Fire Triangle is commonly referenced since it defines the requirements for a fire to exist. According to the principles of the Fire Triangle a fire can only exist if all three sides of the triangle are present and in the proper quantities.
Frequency | Class/Division System | Zone System |
Continuous | Class I, Division 1 | Zone 0 |
Intermittent/Periodic | Zone 1 |
Abnormal | Class I, Division 2 | Zone 2 |
It can be seen that Class I, Division 1 is divided into Zone 0 and Zone 1. The implication is that an area classified as a Class I, Division 1 location
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