Airport T-Hangars

[eewbg]

I am an electrical design engineer. I work on a lot of airport and aviation projects. Historically I, and my company, have designed aircraft T-Hangars to comply with NEC Article 513 - Aircraft Hangars, including provisions for Class I, Division II requirements (as seen by the diagram in the NEC Handbook, Exhibit 513.1). Recently we have been told by many of our airport clients that either in the past at their airport or at other airports in the region existing and new construction T-Hangars have been constructed that do not meet the requirements of Article 513 for Class I, Div II.

I have three questions:
1. Do T-Hangars fall under the NEC definition of Aircraft Hangars in Article 513?
2. If they do, are they not required to follow the requirements set forth in this article with respect to Class I, Div II areas?
3. If a client does not want to follow this requirement, can the Authority Having Jurisdiction "sign-off" on construction not complying with Article 513?

Thank you for your time.

Bart Gilbreath

 

[rcarroll]

1. I don't know what a T-hangar is, but I don't see an exception for it either.
2. IMO, yes.
3. I suppose an AHJ can "sign off" anything he/she wants. However, signing off a blatant code violation does a disservice to the trade.

 

[weressl]

I am an electrical design engineer. I work on a lot of airport and aviation projects. Historically I, and my company, have designed aircraft T-Hangars to comply with NEC Article 513 - Aircraft Hangars, including provisions for Class I, Division II requirements (as seen by the diagram in the NEC Handbook, Exhibit 513.1). Recently we have been told by many of our airport clients that either in the past at their airport or at other airports in the region existing and new construction T-Hangars have been constructed that do not meet the requirements of Article 513 for Class I, Div II.

I have three questions:
1. Do T-Hangars fall under the NEC definition of Aircraft Hangars in Article 513?
2. If they do, are they not required to follow the requirements set forth in this article with respect to Class I, Div II areas?
3. If a client does not want to follow this requirement, can the Authority Having Jurisdiction "sign-off" on construction not complying with Article 513?

Thank you for your time.

Bart Gilbreath

1. They certainly do.
2. Should you determine that you need to modify the design criteria because the physical construction would result in a change in the extent of Division 1 and DIvision 2 areas, you must do so by following NFPA 497. NFPA 513 is just trying to give a quick and dirty way around that since the construction of hangars are similar. However you must review the fuel handling operations in EITHER case to make sure that the extent of Division 1 and 2 areas remain the same.
3. I would insist on a formal interpretation and check it with an OSHA inspector.

 

[rbalex]

I am also unfamiliar with the term ?T-Hangar.? If it is an installation consistent with one of the constructions defined in NFPA 409, then it is subject to Article 513.

Be careful to consider the fuel, if any, that is being used. That alone may indicate no electrical area classification is needed at all. (See the Art 513 Scope statement)