You'll be either a Group III or Group II hangar per NFPA 409 as stated in IBC Section 412.3.6. This depends on your construction type.
Group II hangars require a foam-water deluge system, a combination sprinkler/low-expansion foam system, a combination sprinkler/high-expansion foam system, or a closed-head foam system. A Group III hangar requires only compliance with the IBC, in which case no sprinkler system would be required if the building is under 12, 000 sq. ft. However, if fuel transfer, welding, torch cutting/soldering, doping, or spray painting is performed in a Group III hangar, then compliance with fire protection requirements for Group II is required.