Wood Pellet Mill

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flatlander1982

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Looking at putting together a budget number for a wood pellet mill and somewhat unsure if it would be deemed haz location due to dust. Can anyone point me in right direction, reference NEC
 
Someday someone will teach me this stuff but for now you will have to take my inexperience and best guess. :)

I would look at article 502- class II location

502.1 Scope.
Article 502 covers the requirements for electrical and electronic equipment and wiring for all voltages in Class II, Division 1 and 2 locations where fire or explosion hazards may exist due to combustible dust.
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Thank you. I just met with the builder, who puts these things up nation wide, and he said that he hasn't seen any inspector push the issue for class 1 or class 2.
 
Wood shops used to be considered an H location and everything had to be dust proof, but it was changed several code cycles back in the building code, because they said that you would choke to death first before you reached the amount of saw dust necessary to cause an explosion.
 
WorkSafe said:
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=NEWS_RELEASES&p_id=17235
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That's about what I thought. You can build almost anything and get away with it but when you start running an unsafe work environment then OSHA can step in and shut you down.

I know of a wood shop that should be classified and no one seems to care but that's only because they haven't had the first exposion yet.

It's up to the people that design a facility to make sure it's safe. If that means classified locations then classified they should be. It's not up to the builder nor the electrical contractor to decide what they are going to do with this facility. It is up to the owner and engineers to make sure the design is safe.

Heck I'll wire to what ever set of plans they can get approved but I wouldn't get involved in designing anything. ;)
 
The closest you're going to get in the building code is an F-1 (woodworking) which is a moderate-hazard location.

They took woodshops out, because they are required to have an interlocked dust collection system. If the dust collection system isn't on then the equipment won't come on.

You might find what you are looking for in ANSI/ISA-61241-10 (12.10.05)-2004

I believe that you need to know how many parts per million are in the air in order to classify the area. Remember dust proof doesn't mean explosion proof.
 
Thank you for all of your input. My take on the scituation is that our code is in place to prevent that "one in a million chance" that somthing could happen. Going to get with local inspector and get his take on it, but i feel that the area is deemed hazardous.
 
I've never been required to treat sawmill equipment as a classified area installation. Nor textile processing equipment. We have dust problems in both, but it is of a mechanical nature. It is very common for these locations to "pressurize" the NEMA 12 cabinets from building ventilation (often cooled) air. That limits infiltration.
 
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