Paint spray booth

[sparky984]

I have an enclosed spray booth falling under 516.3(C)(4).

Does the classified location restrictions apply to the openings for the exhaust/make-up air for the mechanical system and the lights that are installed from the outside with a sealed glass on the inside, or would the classified locations only apply to the openings for entry?

 

[cpal]

I have an enclosed spray booth falling under 516.3(C)(4).

Does the classified location restrictions apply to the openings for the exhaust/make-up air for the mechanical system and the lights that are installed from the outside with a sealed glass on the inside, or would the classified locations only apply to the openings for entry?

Usually the lights are behind sealed glass. Class and division is only restricted by the occupancy that the enclosed booth sits in. In body repair shops the height usually loweres the haz loc.

The exaust fans that I have encountered are generally designed so that the wiring is outside the units and not envolved with the haz loc.

 

[sparky984]

Thanks for the input.

 

[sgunsel]

The area within 3 feet of any opening in an enclosed spray booth is a Class I Division 2 area. Normally the lights are behind glass AND 3 feet from the openings. Switches can usually be located beyond the 3 ft distance. Fan motors, as stated above, are usually external to the exhaust stack in a non-classified area. If you are working on a spray booth, you should become familiar with NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials (2007 edition is current). There may be other issues depending on the intended use and equipment to be installed.

 

[weressl]

The area within 3 feet of any opening in an enclosed spray booth is a Class I Division 2 area. Normally the lights are behind glass AND 3 feet from the openings. Switches can usually be located beyond the 3 ft distance. Fan motors, as stated above, are usually external to the exhaust stack in a non-classified area. If you are working on a spray booth, you should become familiar with NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials (2007 edition is current). There may be other issues depending on the intended use and equipment to be installed.

If the booth is under negative pressure then the 3' rule would not be a concern. Does the booth exhaust go into a scrubber? Does the scrubber trap all the volatiles? In that case there may be no Div. 2 around the booth at all.

 

[sgunsel]

If the booth is under negative pressure then the 3' rule would not be a concern. Does the booth exhaust go into a scrubber? Does the scrubber trap all the volatiles? In that case there may be no Div. 2 around the booth at all.

All spray booths operate under negative pressure. Environmental controls, such as scrubbers, thermal oxidizers, or concentrators have NO impact on the classified areas.