Back to Basics is a weekly feature that highlights important but possibly overlooked information that any EHS professional should know. This week, we examine OSHA’s standards for woodworking safety.
Woodworkers can be found in a number of different industries. According to the Bureau of Labor Statistics (BLS), most woodworkers are employed in manufacturing industries, and they are responsible for making a variety of products, such as cabinets and furniture, using wood, veneers, and laminates. Working conditions vary, but many woodworkers are exposed to hazards such as machinery noise and wood dust. According to OSHA, woodworking operations can be hazardous, especially when machines are used improperly or without proper safeguards.
The guidelines for woodworking can be found in OSHA’s standards for general industry, specifically in the subparts for walking and working surfaces, ventilation, occupational noise exposure, hazardous materials, personal protective equipment (PPE), lockout/tagout, powered industrial trucks, and machinery and machine guarding.
Hazards
Woodworkers operating equipment often suffer injuries such as laceration, amputation, severed fingers, and blindness, according to OSHA. They face machine hazards at the point of operation and when there are pinch points and rotary and reciprocating movements. Workers also deal with kickbacks, flying chips and materials, tool projections, fire and explosion hazards, and electrical hazards.
OSHA provides two examples of potential woodworking machine hazards. If not properly grounded, the metal framework of a circular saw could become energized and possibly electrocute and employee. If a worker’s hands were to contact a saw blade, they could have one or more fingers cut off.
Woodworkers face health hazards such as skin and respiratory diseases due to working with wood dust and chemicals used for finishing products. OSHA says most health hazards are associated with long-term exposure to certain substances or to excessive noise levels or vibrations. Some kinds of wood dust can cause allergic reactions, and saw dust is a group A carcinogenic.
Finishes, coatings, adhesives, and solvent vapors can contain chemicals that affect the central nervous system, which can cause headaches, nausea, and dizziness. Exposure to turpentine can result in temporary irritation of the eyes and skin, and even kidney and bladder damage.
Equipment hazard solutions
Employers can implement several procedural and administrative controls in order to protect their workers from equipment hazards, according to OSHA. Workers should be using appropriate equipment for the job, and only using machines for work within the rated capacity specified by the machine manufacturer.
Employers should train workers on machine use and allow only trained and authorized workers to operate and maintain the equipment. Workers must be able to understand the purpose and function of all controls on the machine, how to stop the equipment in an emergency, and the safety procedures for special set-ups. OSHA says operator training should include hazards associated with the machine, how the safeguards protect workers from the hazards, the circumstances under which the guard can be removed, and what to do if the guard is damaged or not functioning properly.
Managers should inspect the equipment and guards frequently to ensure that the operator and machine are equipped with the safety accessories of the job, the machine and safety equipment are in proper working condition, and the machine operator is properly trained. The inspections must be documented, and the documentation should identify the machine, inspection date, problems noted, and corrective action taken.
Equipment must only be used when guards are in place and in working order, and when guards cannot be used, combs, featherboards, or suitable jigs for holding the stock must be provided. Employees must be provided with push sticks or other hand tools so that their hands are away from the point of operation when they work on small pieces of stock.
Electrical hazard protection
All electrical installations must comply with OSHA’s electrical standards, including the following requirements. All metal framework on electrically driven machines must be grounded, including the motor, motor casing, legs, and frame. All circuit breakers and fuse boxes must be labeled to indicate their purpose, and electrical cords, cables, and plugs must be kept in good repair.
Junction boxes, outlets, switches, and fittings must be covered, and all electrical components must be approved by a Nationally Recognized Testing Laboratory. All machines must have a main power disconnect for lockout/tagout.
Additionally, according to OSHA, all machines should have:
- A magnetic switch or other device to prevent an automatic restarting of the machine after a power failure.
- An emergency stop device within reach of operators working in the normal operating position.
- Clearly marked controls that are within easy reach of the operator and away from the hazard area.
Wood dust
Employers can protect workers from wood dust using local exhaust ventilation (LEV), which removes dust at or near the source. According to OSHA, LEV systems can often be integrated with machine guards. Exhaust hoods must be located as close as possible to the emission source, either on the woodworking machinery itself or near the machine. The local exhaust systems must also have an efficient air cleaning device.
LEV systems must be maintained by checking and cleaning ducts and dust collectors at regular intervals. The ducts must be inspected to ensure that they are not loose, broken, or damaged, and V-belts need to be checked on the drive units of belt-driven exhaust fans for slippage or breakage. OSHA provides a list of LEV recommendations for individual machines, including circular saws, band saws, jointers, shapers, planers and moulders, lathes, sanders, and routers.
Noise and vibration
Volume and duration are the primary factors that determine if noise is hazardous. The longer the duration and the louder the noise, the greater potential for hearing loss. Employers can reduce noise levels through three basic approaches to controlling noise:
- Noise source controls
- Noise path controls
- Hearing protection
Noise source controls provide the most effective means of protection, since they actually reduce the amount of noise generated in the workplace, OSHA says. After exhausting source control options first, employers should turn to path controls, and then finally, hearing protection devices.
For vibration hazards, vibration isolators or damping techniques on equipment offer the most effective protection. OSHA recommends isolating machine vibrations from the surface if it is mounted or by use of vibration isolation mounts. Vibrating panels of machine housings and guards can be controlled by applying effective damping materials, such as felts, liquid mastics, and elastomeric damping sheets, to the panels.
A knowledgeable person should determine the correct type and quantity of damping material to use for a particular machine. Factors to consider include the frequency emitted by the machine, the noise reduction level desired, and the weight and size of the machine. OSHA says a good rule to follow is that the damping layer should be the same thickness as the surface being treated.
For more information on OSHA’s recommendations for woodworking hazard controls, click here.