25 October 2004
WOOD SHOP FACILITIES
FUNCTION. Wood shops differ in size and function. Use the design criteria
in this chapter as a general guideline for developing ventilation systems for wood shops.
OPERATIONAL CONSIDERATIONS. A properly designed ventilation
system will control the dust level within the shop. Exposure to wood dust may lead to
health problems. The accumulation of wood dust can create explosion and fire hazards.
Even if a ventilation system is installed to collect most of the dust, manual cleaning at
each machine and throughout the shop is still necessary. Restrict woodworking
exhaust systems to handling only wood dust. Do not connect any other process that
which could generate sparks, flames, or hot material to a woodworking exhaust system.
FLOOR PLAN LAYOUT. Contact the shop personnel who will be working
with the machinery to get their input on workflow and specific equipment. Design the
ventilation system to complement equipment layout and minimize housekeeping.
DESIGN CRITERIA. Design the facility using general technical
requirements in Chapter 4 of this UFC, NFPA 664, Prevention of Fires and Explosions in
Wood Processing and Woodworking Facilities and the specific requirements in this
Exhaust Air System. Calculate the system capacity on the basis that the
system operates with all hoods and other openings, such as floor sweeps, open. Refer
to the ACGIH IV Manual, Chapter 10, for determining the exhaust flow rate for specific
wood shop machines.
System Layout. Lay out the system to meet the shop requirements.
Consider locating machines with the greatest hood resistance as close as possible to
the fan. In most cases, ductwork is located along the ceiling and walls; however,
running ductwork under removable grates or panels in the floor may reduce duct lengths
and leave more working space around machinery. Refer to NFPA 650, Pneumatic
Conveying Systems for Handling Combustible Particulate Solids and 664 for information
on wall penetrations and clearances.
Plenum Exhaust System. An alternative to the tapered system is a
plenum system, described in the ACGIH Manual, Chapter 5. A plenum system allows
equipment to be move equipment in the shop and may be more efficient. Ducts can be
added or removed, as equipment needs change. See the ACGIH IV Manual Chapter 5
for further considerations.
Hood Design. Provide a hood for each operation that produces dust.
This includes sawing, shaping, planing, and sanding operations. Design and position all
hoods so the wood dust will fall, be projected, or be drawn into the hood in the direction