Workbenches and Lab Furniture

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Explanation and Examples of Signal Risk Factors

DRAFT: Not an Official Document.

Signal risk factors are intended to be a quick mental assessment made by people familiar with the jobs' requirements.

It does not require a precise count of minutes or a time/motion study.

Signal Risk Factor Explanation Examples

Performance of the same motion or motion pattern every few seconds for 2 hours continuously, or more than a total of 4 hours, excluding mandatory breaks.

  • The job requires rapid repetition of the same movements which stresses the body parts performing the motion.
  • Different parts of body may be affected, depending on the motion, fingers, arms, neck, knees or ankles.
  • Inserting and tightening 4 bolts in 15 seconds on a moving conveyor line.
  • Intensive data entry requiring rapid repeated keying.
  • Climbing stairs.

Unsupported fixed or awkward work posture for more than 1 hour continuously, or a total of 4 hours, excluding mandatory breaks.

  • Unsupported fixed postures involve holding the arms, back or feet in the same position without support.
  • Awkward postures become a risk factor when the wrist or neck is noticeably bent; the elbow is away from the body (indicates shoulder movement); the back is bent forward, backward or to the side; the knee is bent to kneel or squat.
  • Keying with the fingers and no arm movement, and no forearm support.
  • Sitting without back support.
  • Sitting with the feet dangling.
  • Bending the neck back to see while painting a ceiling.
  • Reaching to get items more than 20 inches away from the worker.
  • Working overhead.
  • Operating a foot pedal while standing.
  • Picking/weeding crops near the ground (not raised beds) by hand or with short handled tools.

Use of vibrating or impact tools or equipment for more than 1 hour of continuous use, or more than a total of 2 hours.

  • Jobs that involve vibration exposure from hand tools such as sanders, grinders and chain saws.
  • Whole body vibration occurs when standing or sitting while operating a truck or other heavy machinery without vibration dampening over rough or uneven surfaces.
  • Polishing metal parts to a high luster.
  • Grinding burrs from machined parts.
  • Cutting out window and door openings with a power saw.
  • Removing mineral deposits with a chipping hammer.
  • Operating an excavator, forestry tractor, or forklift on uneven ground.

Using forceful hand exertions for more than a total of 2 hours.

  • Holding an object that weights 10 pounds or more in the hand.
  • Pinching an object with 2 or more pounds of force.
  • Holding a gallon of whole milk in a plastic container.
  • Holding a gallon can of paint.
  • Pinching open a small binder clip.

Unassisted frequent or forceful manual handling.

  • Lift more than 35 pounds in an awkward posture;
  • Lift more than 35 pounds near the body more than 25 times;
  • Lift 15 pounds or more 2 feet in front of the body more than 25 times;
  • Repeated lifting of more than 10 pounds for more than 1 hour;
  • Pushing or pulling with more than 20 pounds of force for more than 1 hour.
  • Lifting, pushing or pulling adult patients.
  • Repeatedly lifting a case with four gallons of water.
  • Repeatedly lifting 20 pound items from the trunk of a car.
  • Pushing a shopping cart loaded with 5 (40 pound) bags of dog food, stopping and starting for more than one hour.