UFC 4-211-02N
10 January 2005
including change 3, 13 April 2007
The design of the corrosion control hangar should meet the mechanical
requirement set forth in the following paragraphs.
2-4.1
Heating and Air Conditioning.
Provide heating and air-conditioning in accordance with 3-410-02N and as
follows:
2-4.1.1
Based on an economic analysis, consider providing a system for
the recovery of heat from the exhaust air. \ Heat recovery systems must not
permit contaminated exhaust air from migrating into the supply air system. In
particular, heat wheels are discouraged. /2/\ Regardless of the type of system
provided, a detailed, provide in-depth analysis to prove that the airflow introduced
into the paint area is uniform in distribution and velocity, and that the system can
be properly operated for building pressure requirements. Many systems do not
perform as anticipated during the design process, due to lack of foresight of real
world conditions, the influence of building structure, the air delivery system inlet
and outlet conditions, the air exhaust system, the actual aircraft characteristics
and surrounding scaffolding and access equipment, among other things. The
analysis can be performed by scaled mockup, scaled wind tunnel analysis or
Computational Fluid Dynamics (CFD) modeling, among others. The Navy has
also specifically endorsed the use of CFD. Refer to OPNAVINST 4790.2. For
more extensive information on CFD modeling refer to High Performance
Computing Modernization Office (HPCMO), the National Institute for
Occupational Safety and Health (NIOSH), the American Society of Heating,
Refrigeration and Air Conditioning Engineers (ASHRAE), the American Society of
Mechanical Engineers (ASME), the U.S. General Services Administration (GSA)
and the U.S. Environmental protection Agency (EPA) for studies using CFD
analysis for industrial ventilation requirements. It is suggested to employ a third
party consultant to perform these functions. /2/
2-4.1.2
The required hangar bay design heating temperature will normally
be between 24 degrees C (70 degrees F) and 32 degrees C (90 degrees F) with
a relative humidity between 50 and 70 percent. Some activities may require
higher temperatures to accelerate curing cycles. Determine exact requirements
for each site based on materials and production requirements. Equip hangar
with an automatic cutoff of the heating system when the main hangar doors are
open. Minimum temperature thermostat should be set at 1 degree C (34 degrees
F) to override the heating deactivation switch during door-open periods of
subfreezing ambient temperatures. The recovery time for the heating system
should be 30 minutes after door closure.
2-4.1.3
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.
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