Cabinet Shop Classification

[jtester]

I am trying to get a handle on whether and how to classify a small cabinet shop. The guy builds wooden kitchen cabinets, and says he has permanent dust collection on all wood working equipment. Additionally he says he has portable dust collection equipment,(a shop vac, I don't know). Can anyone give me some insight into whether this would be a Class III location throughout, just in part of the building, not at all, etc.?

It seems that the electrical contractor used cast boxes, bell boxes, with threaded entries, but the manufacturer says they aren't dusttight. The inspector is concerned that if this is Class III, the boxes are a problem.

Any thoughts would be appreciated.

Jim Tester P.E.

 

[rbalex]

Re: Cabinet Shop Classification

I would not recommend classifying the location at all. If it were in order, it would more likely be Class II than III. However, unless he does a lot (a WHOLE lot) of fine sanding its simply unlikely he will both generate enough material in supension to create an explosion hazard or greate a flash fire.

Certainly good housekeeping is in order to minimize fire hazard.

 

[jtester]

Re: Cabinet Shop Classification

I've been out of town for a couple of days, so belated thanks for the thoughts.
I visited his shop, and there does not appear to be much, if any, wood flour capable of being suspended in the air. However there is quite a bit of saw dust around. So I'm not sure that Class II is appropriate.
If the dust collection system doesn't work, the sawdust goes everywhere, and that is where I wondered about Class III, although this would be Div 2 at that point.

Thanks again for your suggestions.

Jim T

 

[petersonra]

Re: Cabinet Shop Classification

I don't think that you need to classify something as hazardous because someone might have poor housekeeping.

 

[rbalex]

Re: Cabinet Shop Classification

If you look closely at Article 503 you will see there are virtually no installation differences between Division 1 and 2 in Class III locations.

In my opinion, the most significant design feature in Class III is in 503.1, which establishes the design maximum surface temperatures of equipment. Any surface temperatures that exceed them are already personnel hazards and they aren?t likely to occur in a simple cabinetmaker?s shop. A possible exception would be an electric glue pot.

While the loss of the dust collection system may certainly result in a fire hazard, in this particular operation it would almost certainly occur while ?attended? (including the glue pot). Any mitigation likely to be necessary (a fire extinguisher) is also likely to be readily available.

It?s very difficult to reasonably justify a Class III classification outside a major industrial operation.