Pressurized Air System for Class 1 Div 2 Location

Status
Not open for further replies.
H

hou628

Member
Is there an NFPA requirement for a purged air system in a Class 1 Div 2 panel? I am installing an outdoor panel in an areas normally without hazardous air and am considering using a Type Z system. I am receiving pressure to reduce costs and am reviewing all costs for savings.
 
hou628 said:
Is there an NFPA requirement for a purged air system in a Class 1 Div 2 panel? I am installing an outdoor panel in an areas normally without hazardous air and am considering using a Type Z system. I am receiving pressure to reduce costs and am reviewing all costs for savings.
Click to expand...


If I understand the question correctly, positive pressure inside an enclosure to prevent the build up of gasses during normal operation is one of the methods of reducing the classification from Division 1 to division 2. The distinction between the two classifications for this purpose is that in Div 1 explosive gasses in the proper mixture with oxygen are present during normal operation (a paint booth) division 2 gasses are only present do to an abnormal condition (a relief valve pops off or the area is pressurized so a failure of the pressurization would be required).
 
hou628 said:
Is there an NFPA requirement for a purged air system in a Class 1 Div 2 panel? I am installing an outdoor panel in an areas normally without hazardous air and am considering using a Type Z system. I am receiving pressure to reduce costs and am reviewing all costs for savings.
Click to expand...

There is no requirement to use pressurization at all. There are other protections means that can be used. A type X purge is just one of the ways you can prevent ignition of flammable gases that might become present.
 
Is type X purge an accepted method for making a Class 1 Div 2 location unclassified? NEC says that purging make Class 1 Div 1 unclassified, but it does not clarify if the same is true for class 1 Div 2..
 
It's fine; it's just a big waste of money. Any protection techniques acceptable in Division 1 are acceptable in Division 2. You need to read NFPA 496.
 
Status
Not open for further replies.
Top