MIL-HDBK-1027/1B
3.11.7
Control. Control of the ventilation should be
performed as follows:
a) Before the start of training each day, the
ventilation system should be energized with motorized dampers
open and doors closed (in those structures with doors) to purge
the structure of any unburned fuel which may have accumulated
overnight. The purge should last at least 3 minutes.
b) When treatment equipment is required, a
ventilation system control scheme should be provided to satisfy
the device requirements discussed above, plus the treatment
equipment in an economical manner.
c) Any motorized airflow adjustment device should be
controllable by the device computer. The fans should run
continuously or be off if not needed for extended periods of
time. Floating point motors are for future sophistication.
d) To prevent back spin during startup of exhaust
fans, provide the following:
(1) Individual controls for each fan and have it
interfaced with the DTC.
(2) Each fan should have a two position back spin
prevention motorized damper at the fan inlet. The damper should
remain closed until the fan is started.
3.11.8
Preheat. In extreme climates where the annual heating
degree days is greater than 2000, the ventilation air will
require preheating. In trainers where the trainee walks into
the path of the ventilation air, such as, bilge, berthing, or
trash can fires, the air must be preheated. Where the trainee
does not walk in the air path, as in the pit fire, the preheat
temperature can be reduced for energy savings. The air passing
through the burner rooms in extreme climates should be
preheated. The preheating system should meet the following
criteria:
a) Heating equipment should be sized to heat the
design airflow from the low ambient design temperature to
10 degrees C. (This temperature was chosen because the heating
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