Petroleum-Based Hydraulic Fluids. The following requirements shall
apply, in addition to the requirements described in par. 4.14, to petroleum-
based hydraulic oils in non-mobile equipment:
a) Provide automatic sprinklers directly over, and at least 20
feet (6.1 m) beyond the hydraulic equipment. Complete sprinkler protection is
required if the structure is of combustible construction. Sprinklers may be
omitted near a single small system or multiple adjacent small systems not
exceeding 100 gallon (378.5 L) aggregate capacity, and if the construction is
noncombustible and ignition sources are not normally present, and provisions
exist for automatic or manual shutdown of the system(s).
b) An automatic switch, activated by sprinkler water flow alarm,
fusible link, or other fire detector, shall be provided to shut down the
system if there is 100 gallons (378.5 L) or more of hydraulic fluid.
Aircraft Hangars. Requirements listed in this section are
applicable to fuel cell maintenance facilities, corrosion control and
protective coating, and general purpose maintenance hangars. The following
criteria applies to new hangars and the renovation or modernization of
existing hangars. Existing hangars which are acceptable to the AHJ do not
have to be modified to comply with this handbook. All hangars shall comply
with NFPA 409, Aircraft Hangars, except as modified herein.
For Air Force projects, refer to Air Force ETLs for
Overhead Foam-Water Sprinkler System Requirements. Provide closed
head foam-water sprinkler systems using AFFF in the aircraft servicing area.
The minimum foam-water solution application rate shall be a uniform 0.16
gallon (0.61 L) per minute per square foot (0.093 square meter) of floor area
18.104.22.168 Type of System. Provide wet-pipe foam-water sprinkler systems in
areas not subject to freezing. In areas subject to freezing, provide pre-
action foam-water sprinkler systems. Sprinkler heads shall have a temperature
rating of 286 degrees F. The design area for closed-head systems shall be the
hydraulically most demanding areas listed in par. 4.16.4.
Supplementary Systems. Supplementary protection includes automatic
low-level (under-wing) nozzle systems using AFFF via either fixed or
oscillating nozzles. These systems shall be hydraulically designed, and the
total flow rate of the maximum number of anticipated operating systems shall
be included in determining the total water supply requirements of the hangar.
The flow rate of these systems shall also be included when determining the
capacity of foam concentrate to be stored.
Supplementary Low-Level (Under-Wing) Fixed AFFF System Requirements.