UFC 4-211-02N
10 January 2005
including change 3, 13 April 2007
2-4.1.4
Refer to the facility plates for design conditions in other hangar
spaces.
2-4.1.5
Each bay in the OH area should be a separate heating zone.
2-4.1.6
Heating should be suitable for operation in the vapor hazard
condition in the hangar bay, flammable storage/mixing areas and paint
equipment cleaning spaces.
2-4.2
Ventilation for Control of Air Contaminants and Flammable
Vapors.
2-4.2.1
\ The goal of the facility is to provide a system that is energy
efficient, cost effective to install, while ensuring proper requirements for operator
health and safety are maintained. /2/
2-4.2.2
Provide ventilation in accordance with UFC 3-410-04N, Industrial
Ventilation Systems, NFPA 33 , \ and ANSI Z9.2, 4, and 7; refer to Appendix B
for further guidance. /2/ The ventilation system for the hangar area should
furnish 100 percent filtered outside air at a horizontal laminar flow velocity of 0.68
\ 0.508 /2/ m/s (100 fpm) across the entire cross-section area of the hangar
bays for chemical stripping/painting operations for worker safety and overspray
control \ in accordance with OSHA. This velocity may be decreased in
accordance with OSHA and its interpretations for consideration of paint spray
areas vs. paint booths, depending on the size of aircraft and the exact type and
amount of operations considered for the space. Recirculation of airflow may be
evaluated according to requirements of NFPA-33 and ANSI Z-9.7. Refer to the
extensive studies and information provided by the Air Force Research laboratory
(AFRL) in appendix B and other sections for more information. Refer to
applicable OSHA interpretation in appendix D. /2/ 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. \ Refer to UFC-3
410-04 for fan requirements. /2/ Provide demister in the supply system.
2-4.2.3
\ The use of High Volume Low pressure (HVLP) and HVLP
electrostatic paint application techniques greatly reduces the amount of
overspray exposure to workers, versus conventional air atomization air-assisted,
air less, or electrostatic paint spray methods, and is recommended to reduce
overspray and increase exhaust filter life. When HVLP and /or HVLP electro-
static paint techniques are used over spray is greatly reduced as well as potential
health effects to the workers. Verify systems performance to ensure system is
not over designed. /2/
2-4.2.4
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. \ Filter pressure, space pressure, fan status, breathing
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