Intrinsic Safety & Thermal Imaging Part 2

Last month, we reviewed the origins of the need for and the standards surrounding electrical safety ratings as well as some of the terminology related to the topic. This month, we delve into design considerations and address some of the most common...


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Adding to the confusion is the fact that the Class/Division/Group designations are valid only in North America. Elsewhere, the International Electrotechnical Commission (IEC), European Committee for Electrotechnical Standardization (CENELEC) and others have moved to a system that consists of Zones, Gas Groups, Equipment Protection Level and Temperature Classification to describe hazards, environments and equipment. While there are some direct correlations between the IEC and NEC standards, there are also IEC approvals for which there is no direct NEC approval. The push is on for harmonization of these two codes, and it appears that the IEC system will triumph, signaling that the end of the NEC system is likely in sight. In support of harmonization, North American standards will allow for NEC or IEC classifications of locations and certifications of devices.

To further complicate matters, under the CENELEC standard, “Intrinsically Safe” refers to any device that is Class I, Division 2 and above. Several manufacturers of electronic and battery-powered devices advertise them as “Intrinsically Safe,” but in some cases they are combining the technical accuracy of a European approval with the common vernacular of the North American user. In this case, the customer is thinking Class I, Division 1 and the actual certification is technically equivalent to a Class I, Division 2 rating.

 

Conclusion

Caveat emptor! You must ask the technical detail of any stated rating. The buyer must decide what level of protection is desired. To what environments will the firefighter be exposed? To what environmental conditions will the firefighter be exposed?

The topic is technical and confusing, but if I was a hazmat technician preparing to enter a “hot zone” to address a leaking pressurized gas cylinder, I would want to know what my devices are certified for. Generic terms would not cut it for me and they should not cut it for you. n