On guard

Do you have compactors, conveyor belts, crushers, saws and other machinery with rotating parts at your recycling facility?

Having performed machine guarding at numerous recycling facilities, the answer is almost assuredly, “Yes.”

Machinery is great for reducing labor intensity and increasing productivity; however, when improperly guarded, machinery may result in severe worker injuries as well as in fatalities.

This article will cover the following safety topics:

• machine guarding fundamentals;
• applicable regulations; and
• machine guarding techniques.
  
   

Fixed fundamentals

Several mechanical motions and actions can present a hazard to workers in a recycling facility. For example, the movement of rotating members, reciprocating arms, moving belts, meshing gears, cutting teeth and any parts that impact or shear can harm employees if not properly guarded.

Let’s review several fundamentals of machine guarding:

• Nip points are created by rotating parts on machinery. An unguarded air compressor belt would illustrate this potential workplace hazard.
• The point of operation is where work is performed on the material—where the rubber meets the road, so to speak—such as cutting, shaping, boring or forming of stock. With a shredder, for example, it would be where the material is shredded.
• The power transmission apparatus comprises all the components of the mechanical system that transmit energy to the part of the machine performing the work. These components include flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks and gears.
• Rotating parts move while the machine is operating. These can include reciprocating, rotating and transverse moving parts as well as feed mechanisms and auxiliary parts of the machine.
• Shear hazards are created by a moving part, such as a knife or blade, and a fixed part. The point where the blade contacts the raw stock is a potential shear hazard and must be guarded.
  
   

Rugulations and standards

Recycling companies operating in the United States are required to comply with OSHA (Occupational Safety and Health Administration) regulations. OSHA 29 CFR 1910 Subpart O addresses machine guarding. Essentially, all machinery within 7 feet of an employee must be guarded.

Machine guarding regulations include:

• 1910.211: Definitions;
• 1910.212: General requirements for all machines;
• 1910.213: Requirements for woodworking machinery;
• 1910.215: Abrasive wheel machinery;
• 1910.216: Mills and calenders in the rubber and plastics industries;
• 1910.217: Mechanical power presses;
• 1910.218: Forging machines; and
• 1910.219: Mechanical power-transmission apparatus.
  
   

Mandatory techniques

Proper machine guarding fully protects the worker against placing any part of his or her body into any part of the machinery that could cause injury. Some examples of machine guarding are barrier guards, two-hand tripping devices, electronic safety devices and so on.

It is important to emphasize that sometimes more than one form of guarding is necessary to fully protect the worker. For example, a crusher may have expanded metal guarding to protect against moving machinery and a light curtain to stop the machine if a worker’s hand is placed too close to the point of operation. From my experience, recycling machinery typically has at least two forms of guarding.

Machine guarding is an art, not a science. Sometimes, especially with older machinery, several different guarding approaches should be considered to ensure effective worker protection.

W. Jon Wallace, CSP, MBA, is a safety consultant with more than 26 years of occupational safety experience. He also is an adjunct assistant professor at The University of North Carolina at Chapel Hill. He can be reached by email at jwallace@workplacegroup.net or by phone at 919-933-5548.