Class 1, Div 1 Distance Requirements

[derrick1]

Is there a certain distance that a non-explosion proof device can be in a class 1, div 1 area? For example, we have a room that is class 1, div 1. If the non-exp device is 10 feet away from the 'source' (flammable liquid), is that ok? Or it can't be in this area at all? (There is a door between this device and the source.

Thanks

 

[psafety]

derrick1,
If in the "classified area" the component should meet the criteria for that classification.

 

[DM2]

You need to take a look through NFPA 497.

You'll find that in open areas, the Class 1, Division 1, area is limited to a distance 5' from the source. The Class 1, Division 2 area is limited to a distance of 10' from the source.

In any case you don't want to make the determination as to where the Class 1, Division 1 area ends and the Class 1, Division 2 area ends. In many applications this has already been defined, which is typically the case in offshore applications.

A good reference is the "Crouse-Hinds Code Digest 2005". You can download this from the web at:

http://www.crouse-hinds.com/crousehinds/resources/codedigest_2005.pdf

Regards
Dan Marr
Dan.Marr@DM2-Inc.com