Hangar Bay Detection
Provide triple-IR optical flame detectors in the Aircraft Hangar Bays. These shall be connected
to the suppression system-releasing panel and shall activate the low-level AFFF System. This
panel shall be separate from the building fire alarm panel. For speed of activation use a non-
addressable releasing panel.
Emergency Shut-off Stations
Provide a "deadman" type emergency shut-off facility for the low-level AFFF system. Operation
of these stations shall stop the flow of foam and water to the low-level system. The stations shall
be non-latching and require continuous depression to maintain a stop of the system. Release of
the stations shall return the system to operation. Actuation and release of the stations when the
low-level system has not been activated shall have no effect.
Fire Pumps, when required, are a part of the project scope. The fire protection requirements
should be evaluated to be able to utilize a single set of pumps in lieu of providing pumps for
multiple hangars. The design agency should provide for adequate space to accommodate the
pumps and facilitate their maintenance. Consideration should be given to accommodate the
pumps in a separate building.
Structural System Protection
NFPA 409 requires that all main steel structural columns in the hangar bay be made fire resistant
using listed materials and methods to provide a fire resistive rating of not less than 2 hours.
Fixed water systems, as an extension of the overhead sprinkler system, shall be permitted in lieu
of a 2-hour fire resistance rating, if such systems are specifically designed to protect the
The water supply shall be capable of maintaining water discharge for the combined low-level
sprinkler systems at the design rate for a minimum of 45 minutes.