MIL-HDBK-1028/1C
The recovery time for the heating system should be 30 minutes
after door closure.
c) Provide a snow-melting system at the hangar door
tracks when the outside design temperature is -4 degrees C (+25
degrees F) or lower and when historical snow data supports the
requirement.
d) Refer to the facility plates for design conditions
in other hangar spaces.
e)
Each bay in the OH area should be a separate heating
zone.
f) Heating should be suitable for operation in the
vapor hazard condition in the hangar bay, flammable
storage/mixing areas, and paint equipment cleaning spaces.
3.4.2
Ventilation for Control of Air Contaminants and
Flammable Vapors. Ventilation should be provided in accordance
with MIL-HDBK-1003/17, Industrial Ventilation Systems, and
NFPA 33. The ventilation system for the hangar area should
furnish 100 percent filtered outside air at a horizontal laminar
flow velocity of 0.51 m/s (75 fpm) across the entire cross-
section area of the hangar bays for chemical stripping/painting
operations for worker safety and overspray control. Provide
0.25 m/s (50 fpm) airflow velocity during the drying cycle and
de-paint by grinding operations, and a minimum of 6 air changes
per hour for other procedures. Fans should be direct drive or
vane axial for supply and exhaust. Provide demister in the
supply system. Interlock the fans and the compressors so that
the compressors cannot operate when the fans are inoperative.
Interlock the fans and the fire protection system so that the
fans cannot operate when the fire protection system is
inoperative. The ventilation system should maintain a slightly
positive static pressure of 1.25 mm (0.05 in.) water gage
between the hangar area and the exterior to avoid infiltration
of contaminants into the hangar space which can affect painting
operations. Maintain a slightly higher pressure in the adjacent
ancillary spaces and overhead ceiling spaces than in the hangar
area to keep the hazardous fumes given off by stripping agents
from infiltrating into these spaces. Ventilate the space above
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