Class 1 Div 1/Unclassified Boundary

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Timpi Electric Solutions

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Greetings,
I'm currently working on a Class 1 Div 1 room that is adjacent to an unclassified area. A service door connects the two locations. I can't seem to find anything in the NEC that addresses how close circuits and devices in unsealed conduits can be from the door of the hazardous location. For example, there is an existing receptacle less than six feet from the entrance, I need to feed a NG boiler that plumbers will be installing outside the hazardous location, and I need to install a switch for the luminaires inside the hazardous location. Can anyone reference the distance requirements from a door to a class 1 division 1 location?
 
Unless an installation is subject to one of the Articles from 511 to 516, it cannot be directly classified from the NEC, and without knowing the specific details of the installation your questions cannot be answered directly.

The facility is nevertheless required to have hazardous locations "properly documented" per Section 500.4. The Section also lists several reference standards that may be consulted in the Informational Notes (IN). It is best to have a knowledgeable person with a detailed understanding of the installation create the documentation.
 
The general contractor is rather uninformed and the engineer has been less than involved. It is a paint storage and mixing room in a trailer painting facility. The room will be mechanically ventilated, but we've already been waiting three weeks for an answer on how and with what electrical specifications.

Referencing NFPA-33 6.5.2, it states that the area within 3 feet in all directions of an open container, etc., is class 1, division 1; 2 feet out in all directions beyond that is class 1, division 2; and an additional 5 feet out up to 18 inches above ground is class 1, division 2. But, I couldn't find anything referencing doorways in enclosed handling areas in NFPA 30 or 33.

NFPA 33 section 6.5.4 states that any devices within 3 feet of an opening of an enclosed spray room with interlocked ventilation must be suitable for class 1, division 2. This is also stated in NFPA 70 article 516.3C4. It is a mixing room not a spray room, though.

Nothing quite fits my circumstances and I frankly don't expect much from the engineer.
 
I confess I had to refresh my memory, but NFPA 33, 6.5.2 doesn't apply to your installation either.

Again I must emphasize the classified locations should be properly documented by someone who knows what they are doing. Unfortunately, while proper documentation is a Code requirement (Section 500.4), "someone who knows what they are doing" is not so clear. Nevertheless, the owner/operator of the facility is obligated to have it done. Most jurisdictions would hold that the statement, "This documentation shall be available to those authorized to design, install, inspect, maintain, or operate electrical equipment at the location." heavily suggests it must be done before your activities have begun.

Just curious - how do you know the room is Class I, Division 1 in the first place?
 
That's the crux of my problem; I can find nothing in any of the obvious NFPA publications that seems to completely cover my exact circumstances. While I understand that this is not supposed to be my responsibility, I has become my problem regardless.

I don't think the general contractor has any experience with hazardous locations, as he did not even know that an explosion proof ventilation fan was required until my boss told him. Three weeks later, we still have no answer as to what fan will be used, where it will be placed, whether it will be an explosion proof fan inside, or a non-explosion proof fan outside, where air will be drawn from, etc. That's why I'm not hopeful to receive anything from the engineer. It's just trying to determine the safe and legal solution to a crap situation.

Nobody even explicitly stated that it is class 1, division 1, but it has to be based off of the way they operate their current mixing room. There are open can of paint and acetone all over, spilled chemicals cover the floors, and they transfer fluid from one container to another with measuring cups and scales before mixing it. It is part of the RV manufacturing industry, which is huge in my location and notoriously puts profit before anything else, and are proponents of the philosophy of getting work done quickly and cheaply rather than producing a quality product. It doesn't help that this county, which we don't often work in, is somewhat of a joke regarding code and inspections.

I will cite my boss 500.4 and see if he can put any pressure on the contractor. I'll also see if he can dig up any documentation on the old mixing room.
 
beck693 said:
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Nobody even explicitly stated that it is class 1, division 1, but it has to be based off of the way they operate their current mixing room.
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Oddly enough, that might be sufficient - IF it gets properly documented AND sufficient experience with similar installations can be validated.

Since no specific standard applies directly to your installation, NFPA 497 (a general standard) may often be applied. NFPA 30 may also be of benefit.

There are many factors to be considered, so again, get someone that knows what they are doing (and why they are doing it) to create the documentation.
 
Seems to me the AHJ would ask to see that documention. To the OP, I would suggest a statement in your bid documents about the area classification per 500.4
 
tom baker said:
Seems to me the AHJ would ask to see that documention. To the OP, I would suggest a statement in your bid documents about the area classification per 500.4
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While I agree, the OP noted in Post#5 that local enforcement is some what lacking. I would also suggest the facility's insurer take a peek.
 
To put things in perspective - and I tried to upload a picture but the file was too large - yesterday I found an extension cord with two phone chargers and a desk fan connected in the old mixing room. When I confronted the operator this morning his response was, "I've been doing this for ten years, I know. I ain't in fear. If it blows up and takes me and everyone else, I guess that's what we're all looking for." This is the environment that I'm stuck with. Never, ever buy an RV because these are the people building them.
 
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