Transitioning to Zone Approach from Class/Division

fifty60

Senior Member
I am most familiar with the NFPA 70 2017 approach to Class/Division. I know that alternatively, the Zone approach is acceptable. For Class/Division, I mainly rely on API/RP 500 as a resource, as well as various NFPA document like NFPA 497 and NFPA 30.

I would like to learn more about the Zone approach. One document that I am looking at is IEC 60079-10.1 Classification of areas - Explosive gas atmospheres. Would this document be helpful in applying the Zone approach, or should I not reference it since it is an international standard?

I would like to know what standards I should study to educate myself on the Zone approach. My main interest is getting a better approach to classifying areas. I understand that the IEC approach allows for a more accurate/engineered approach to area classification. I am not sure if I am confusing the IEC approach and the Zone approach as a singular thing, or if they are two seperate things and do not mix well.
 

rbalex

Moderator
Staff member
NFPA 497 (latest edition) covers both Divisions and Zones, APR RP505 addresses Zones. However, see NEC Section 505.7; especially Subsections 505.7(A), (B), and (C) - but read the whole section.
 

rbalex

Moderator
Staff member
Last, but not least, if you want a more analytical approach, review Appendix D and the following Appendices in API RP505. Quite honestly, I don't believe you will save much in general but there are occasions it's worth the look, especially when you review the fugitive emissions.
 

fifty60

Senior Member
Understood, thank you very much for your words. It sounds like the point source method called out in Appendix D is about as analytical an approach as I will find.
 
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