Turnaround and requirement of area classification

[Electrometrical]

(1) During the turnaround then the units are completely steamed out and shutoff in a refinery setting, would we still need to observe area classification for bringing temporary (non classified) electrical equipment in the area?

(2) What about a situation where the units are shutoff and steamed out gradually. Can we bring temp (non classified) electrical equipment in that particular unit which is off however its adjacent units are live? What does CSA or NEC address this issue?

Thanks in advance for your help and comments.

 

[alehman]

Area classification cannot be determined without a thorough engineering analysis. If there is some way to assure a hazardous environment can't exist, I would think it would be OK. This would be up to your local building authority, insurance carrier, etc. the NEC does not address this.



Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[juleselec]

Presumably at the start of the shutdown, all the flammable material in the pipework will be bled to atmosphere and all valves preventing flammable material into the work area have been identified and tagged.

In that case, it is standard practice to use non-hazardous rated equipment in the area. Many sites will have gas detection / monitoring equipment installed in case flammable gases float over from other areas of the plant or there is a leaky valve, etc.

Actually, you should really consult the hot work permit instructions that are relevant to your site. That should have all the requirements you're looking for. Having said that, during a partial plant shutdown / turnaround, most of these considerations will be taken care of by the shutdown engineering team in conjunction with operations.