CHAPTER 7 WOOD SHOP FACILITIES

7-1 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。

7-2 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。

7-3 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。

7-4 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 chapter。

7-4。1 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。

7-4。1。1 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。

7-4。1。2 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。

7-4。2 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

of the airflow。 Construct hoods of noncombustible materials。 Ensure the hoods do not interfere with worker operations。 In some cases, the exhaust hood may be utilized as a safety guard。  Refer to the ACGIH IV Manual, Chapter 10 for woodworking hood designs。 Modify the drawings as necessary to meet the specific equipment and process requirements。

7-4。3 Floor Sweeps。  If the design includes floor sweeps, include a means, such as magnetic separators, to prevent scrap metal from entering the system。 Figure 7-1 shows a basic floor sweep design。 The floor sweep is only opened during shop clean up。 If the system design calculations indicate that, when opened, the floor sweep provides a transport velocity of less than 17。78 m/s (3,500 fpm,) design the system to include floor sweeps in the normally opened position without a hinged cover。