10-3。1。3 Grinding Mode。  Provide vacuum exhaust grinding tools to remove dust during operations。 The grinding process should be controlled separately from the painting and drying processes。 When feasible, grinding should be performed in a separate grinding booth。

10-3。2 Ventilation System Configurations。  Design or specify the entire exhaust air system using criteria for a crossdraft hangar configuration。 Figure 10-1 is one method of designing hangar airflow distribution。 When considering alternatives to the perforated supply plenum doors, the designs should introduce the make up air in a laminar manner and minimize the creation of dead air pockets。 This will help to capture the paint overspray and reduce the possible build up of contaminants。

Figure 10-1。  Crossdraft corrosion control hangar。

NOTES:

1。 Size each plenum take-off for no more than 2。44 m (8 ft) of plenum width (W)。 Size the exhaust plenum for a maximum plenum velocity of 5。08 m/s (1,000 fpm)。

Size the replacement air plenum for a maximum plenum velocity of 2。54 m/s (500 fpm)。

2。 See Figure 10-2 for hangar doors and exhaust plenum details。

Figure 10-2。  Hangar door and exhaust plenum details。

NOTES:

1。 Size open area for an airflow velocity of 10。16 m/s (2,000 fpm) through holes。

2。 Size open area for an airflow velocity of between 3 to 3。5 m/s (600 to 700 fpm) through holes。

10-3。3 Exhaust Filtration System。  See paragraph 9-3。1。2

10-3。4 Auxiliary Walk-in Paint Spray Room。  See Chapter 9 for a paint spray room design。

10-3。5 Storage and Mixing Room。  Refer to the ACGIH IV Manual, Paint Mix Storage Room, VS-75-30 for ventilation system design。

10-3。6 Paint Mixing Hood。  See paragraph 9-3。3。

10-4 FANS AND MOTORS。 Use explosion proof motor and electrical fixtures for exhaust fan。 Do not place electric motors, which drive exhaust fans, inside hangars or ducts。  See paragraph 2-4。2 for more detailed information about selecting a fan。

10-5 REPLACEMENT AIR。 Design the replacement air system to maintain a neutral air pressure inside the hangar。 This will prevent dust from entering the paint

spray area or paint overspray and vapors from escaping and migrating into adjacent work areas。  See paragraph 2-4。5 for detailed design criteria。

NOTE U。 S。 Army and U。S。 Air Force: Design the replacement air system at Army facilities to maintain a slightly negative air pressure inside the hangar。

10-5。1 Heating and Air Conditioning。  See paragraph 2-4。5。

10-6 SYSTEMS CONTROLS。 Design system controls in accordance with paragraph 2-5。

10-7 RESPIRATORY PROTECTION。  See paragraph 2-7。3。

GLOSSARY

Air cleaner A device designed for the purpose of removing atmospheric

airborne impurities such as dusts, gases, vapors, fumes, and smoke。 (Air cleaners include air washers, air filters, electrostatic precipitators and charcoal filters。)

Air filter An air cleaning device to remove light particulate loadings from normal atmospheric air before introduction into the building。 Usual range: loadings up to 0。0069 g/m3 (3 grains per thousand ft3)。 Note: Atmospheric air in heavy industrial areas and in-plant air in many collectors are then indicated for proper air cleaning。