Yes, a hangar that exceeds 2000 square feet and 20 feet in
building height cannot be considered a residential aircraft
hangar subject to Section 412.5. Instead the hangar would
be subject to Section 412.4.

There are generally three separate conditions that could
dictate when or if an aircraft hangar building is required
to be sprinkled. They include:

a. Aircraft hangar building “Group” designation
classified in accordance with NFPA 409, per FBC Section
412.4.
b. FBC Section 903.2.9 - for Group S-1 hangar
buildings over 12,000 square feet in area,
c. Aircraft hangar buildings without proper exterior
wall openings – per FBC Section 903.2.11.1.

Each of these conditions must be verified separately to
determine if the hangar building is required to be
sprinkled or not.

The Requester has not supplied the type of construction or
the actual square footage of the proposed hangar.

Additionally, information relating to the exterior wall
openings in the hangar has also not been provided.

Let’s assume the square footage is 5000 square feet or
less; regardless of the type of construction, the hangar
would be classified as a Group III hangar (read across the
bottom line of Table 412.4.6).

For Group III hangars, fixed fire protection systems are
not normally required unless, according to Section
412.4.6.1, there are hazardous operations such as fuel
transfer, welding, torch cutting, spray painting, etc.
performed in a Group III hangar. In this case the hangar
would need to meet the fire protection requirements
of a Group II aircraft hangar.

Additionally, if the hangar door is greater than 28 feet in
height, the hangar would be classified as a Group I
hangar regardless of area, see footnote a. of Table 412.4.6.

Chapter 9 must also be considered. This aircraft hangar is
an S-1 occupancy. All Group S-1 occupancy aircraft hangar
buildings are required to be sprinkled when their building
fire area exceeds 12,000 square feet in area (per FBC
Section 903.2.9.1), or when they do not have proper opening
around their perimeter (per FBC Section 903.2.11.1).
Both requirements must be checked to be sure of sprinkler
requirements for S-1 aircraft hangars.

According to the commentary, a hangar that exceeds the
limitations of Section 412.5 must then meet other
applicable code provisions, including; compliance with fire
separation, adequate means of egress, smoke detection and
alarms, independent mechanical and plumbing systems and
height and area limitations.