Technical data

5.2.1 Respiratory Protection. Many toxic materials are
found in spray painting shops which may impair the health of
personnel if control measures are not provided. Harmful
concentrations of these materials may be reduced to a safe
level by an efficient mechanical exhaust system supplemented
with personal respiratory protection. At a minimum, it is
recommended that powered air purifying respirators with
hood be used (see Table C-1); however, always contact
Bioenvironmental Engineering for selection of proper respi-
ratory protection. It should be understood that a respirator is
not a substitute for a proper exhaust system, but is a
supplement to existing ventilation methods (refer to NFPA
91; and AFOSH 48-8, and 48-137).
NOTE
This manual provides only general information
for respiratory safety devices. See the manufac-
turer’s technical data for detailed operating and
maintenance instructions. See the DO43 System
for NSNs) and to convert specification and part
numbers to NSNs. Equipment Authorization In-
ventory Data (EAID) authorization for equipment
type items must be established in accordance
with AFMAN 23-110, Volume 2, Part 2, Chapter
22.
5.3 SPRAY BOOTHS AND PAINTING AREAS, GEN-
ERAL.
Spray painting shall be conducted in a properly ventilated
spray area such as in a spray booth which confines and
exhausts vapors and mists and overspray during painting
operations. Paint booths are available in various sizes for
small parts painting, or for larger wheeled equipment, and can
be large enough for complete aircraft. Air flow design shall
provide adequate velocity at the face of the booth. Basic
airflow criteria for a specific type paint booth is available
from the Bioenvironmental Engineer. Also, see NFPA 91;
“Industrial Ventilation, A manual of Recommended Prac-
tices” published by the American Conference of Government
Industrial Hygienists (ACGIH), and AFOSH STD 91-17. For
additional reference criteria, see the Air Force Corrosion
Facility Reference Guide on the Air Force Corrosion Preven-
tion and Control office’s website. Doors and windows in the
area should be kept closed to exclude dust and dirt. Air should
enter a booth at a rate which will not cause turbulence or
excessive air currents but be sufficient to keep dried over-
spray from settling on surfaces which have been painted and
are still tacky. Humidity and temperature indicators shall be
installed and kept in proper operation so that the temperature
and humidity for correct spraying can be checked and
maintained. Lighting shall amply illuminate all surfaces
being painted, and all lighting and connecting electrical
switching shall be explosion proof. Spray room surfaces shall
be cleaned frequently to ensure good housekeeping.
5.4 PAINT BOOTH TYPES.
Prior to spraying of paint, rigidly comply with all
safety regulations regarding to electrical ground-
ing, fire prevention, vapor and explosion-proof
lights, etc.
Two types of paint spray booths are in general use, the dry
type and the air-water wash type. Traditional spray booths are
generally effective at removing particulate matter such as
solid and liquid particles of overspray, but they do not remove
solvent vapors from exhaust air. Removal of solvent vapors
for air quality emissions compliance requires supplemental
equipment to collect the organic vapors on activated charcoal
filters or to destroy them by combustion or catalytic reaction.
These special process capabilities are matters to be addressed
by local civil engineering and environmental planning func-
tions.
5.4.1 Dry-Type Booth. Dry-type spray booths draw
contaminated air through a series of baffles or filters before
exhausting it to the outside. Care should be taken to minimize
air currents in the spray booth that will interfere with removal
of spray dust or with the health and comfort of personnel.
These booths are available with varying types of filter
material, and local environmental regulations may specify the
numbers of filter banks required. In most cases, the filter
material will be considered a hazardous waste; and disposal
should be coordinated with local civil engineering and
environmental management.
5.4.2 Air-Water Wash Type Booth. In addition to the
baffles used in the dry-type booth, this type of spray booth has
a series of water curtains to trap and remove overspray solids
and liquids from contaminated air before it is exhausted. An
air-water wash type booth will remove up to 95 percent of
paint residue before it is exhausted when working properly.
Many areas today have greater restrictions than 95% effi-
ciency. Fire hazards are greatly reduced when the air-water
wash booth is used. A deflocculating material or water wash
compound is added to the water to prevent residue from
adhering to the working portion of the booth, and also serves
to prevent rusting. A paint sludge removal system may be
installed in these booths to decrease the frequency of chang-
ing the water. Disposal of paint sludge may be considered a
hazardous waste and should be coordinated with local civil
engineering and environmental management.
TO 1-1-8
Change 1 5-3