25 October 2004
Spray Up Booths. Design a spray up booth as shown on Figure 5-4.
Use the spray up hood design in shops where spray up and lay up are performed in the
same booth. Separate operations in this booth from any cutting, grinding, and sawing
operations when conventional hand tools are used.
Ventilated Workbench and Sink. Design a ventilated workbench as
shown in Figure 5-2 for small work pieces. Use a similar workbench for resin
preparation and mixing as shown on Figure 5-5. Eliminate the drawers and increase
the size of the hood face by extending it to the floor if 55-gallon drums are used during
resin preparation. Use aqueous emulsion cleaners to reduce styrene and acetone
Ductwork. Design a 17.8 m/s (3,500 fpm) minimum transport velocity for
LVHV hand tools, and grinding and spray up operations to prevent particulate material
from collecting in the ductwork.
a. Size the ductwork carrying vapor generated during lay up and mixing
operations for a minimum transport velocity of 12.7 m/s (2,500 fpm). Use sheet metal
as duct material since it is non-combustible. Route the ductwork directly to fans located
outdoors. See paragraph 2-4.1 for further information on ductwork.
b. Consult with a fire protection engineer and use UFC 3-600-01 to
design a fire protection system for the ductwork when required. Condensation of
flammable vapors, i.e. styrene and acetone, may occur and pool in the ductwork as it
passes through an area with a lower temperature.
Fans. See paragraph 2-4.2 for general considerations.
Weather Stack Design and Location
. See paragraph 2-4.3 for exhaust
stack design guidance.
Air Cleaning Devices. Use separate air cleaning devices for grinding,
buffing and polishing operations where particulate material is generated. Use separate
air cleaning devices for lay up and mixing operations where flammable vapors are
generated. Consult the air pollution control authorities for details on local requirement.
Grinding Operations and Hand Tools. Use a fabric collector for grinding
operations and LVHV hand tools. Consider using a disposal chute with a motor-driven
rotary air lock in shops with a large particulate volume.
Spray Up Operations. Spray-up operations release a combined
contaminant of wet resin laden fiber and organic vapors. Therefore, separate spray up
operations from all other operations. Install an air-cleaning device for vapors. Install
layered prefilters on the spray up hood face instead of the perforated plate to prevent
wet airborne resin from hardening in the ductwork and collectors. Peel off and discard a
layer of the prefilter when its surface becomes loaded as indicated by the hood static
pressure gauge. This continues until only the base filters remain. After that, replace the