Aircraft Hanger Article 513.3(B)

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GamecockEE

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Appreciate your replies, always amazing how it helps to have someone else reading to direct one to the right conclusion when dealing with the NEC.
 
Aircraft Hanger Article 513.3(B)

Have a question concerning the proper classification for a small, private aircraft hanger. The code article in question states that the entire hanger up to 18" AFF shall be considered to be a Class 1, Div. 2 area. Does the title of the sub-article, "Areas Not Cut-Off Or Ventilated" imply that if adequate mechanical ventilation was provided, then this hanger space would become unclassified? thanks for the input!
 
No. Read on to (D) - Areas Suitably cut off and ventilated.

The vicinity of the aircraft is always classified. Other areas, like an adjacent break room, are also classified if not cut off and provided with ventilation.

Steve
 
The entire area of the hangar is required to classified. The classification does not extend into areas that are suitably cut off (513.3(B)). Areas that have communicating openings into the hangar space are required to be classified unless ventilated (513.3(D)).

It is interesting that the title of 513.3(D) reads "Suitably Cut Off and Ventilated" but if the area is cut off, and is not required to be classified in the first place, why would you need ventilation?
 
RB1 said:
The entire area of the hangar is required to classified. The classification does not extend into areas that are suitably cut off (513.3(B)). Areas that have communicating openings into the hangar space are required to be classified unless ventilated (513.3(D)).

It is interesting that the title of 513.3(D) reads "Suitably Cut Off and Ventilated" but if the area is cut off, and is not required to be classified in the first place, why would you need ventilation?
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513.3 Says areas "shall not be classified where adequately ventilated AND effectively cut off".

So it has to be both to be unclassified. Cut off, and ventilated.

If its not cut off, ventilation won't stop flammable liquids from running in, and "cut-off" won't keep vapors from building up. Either possibility makes the area classified.

Steve
 
Steve:

Section 513.3(B) The entire area of the hangar, including any adjacent and communicating areas not suitably cut off from the hangar, shall be classified as a Class 1, Division 2 location up to a level 18 in. above the floor.

Therefore areas that are suitably cut off are not classified. Why do I have to ventilate an unclassified area?
 
RB1 said:
Therefore areas that are suitably cut off are not classified.
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513.3(B) doesn't say that at all. 513.3(B) doesn't say anything about areas that are cut off. So you have to read on to 513.3(D) where it specifically says only areas cut off and ventilated are unclassified.

Steve
 
RB1 said:
Steve how did the vapors build up through an unpierced partition?
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The last part of 513.3(D) is a little more specific about "cut off". It says:

"cut off from the hangar itself by walls or partition's"

But that is still pretty vague. Is a partial height wall a "partition"? Maybe so. At any rate, there is nothing that states "cut off" means air tight. So vapors can still find their way in.

Even if you think "cut off" means air tight, vapors could travel into our "cut off" space through a door that someone opened.
 
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