Ergonomics in the Laboratory

Purpose

Laboratory work activities can introduce ergonomic risk factors that are associated with muscular-skeletal disorders (MSDs). Prevention of MSDs requires the recognition and control of ergonomic risk factors in the design and modification of workstations and procedures. This guidance will provide laboratory workers and supervisors with recommendations to control ergonomic risk factors.

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Ergonomic Risk Factors

Awkward postures occur when body parts are positioned away from their neutral position. These postures can put stress on the joint and its associated muscles. Long durations and the wider degree of positioning away from the neutral position may increase the severity of the risk. Examples include: flexion/extension of the wrist, abduction of the shoulders (“winged elbows”), flexion of the shoulders (reaching overhead), bending/twisting at the waist, and bending the neck.

Contact stress is a sustained contact between a body part and an external object. Examples include: resting the wrist or forearm against a sharp edge/corner.

Duration is the period of time that a body part is exposed to an ergonomic risk factor. Longer durations of exposure increase the severity of the risk.

Force exertion is the physical effort applied by a body part to perform a task. Higher forces and/or longer durations can increase the severity of the risk. Examples include:  Pushing/pulling, lifting, gripping, and pinching.

Forceful impact is a motion where a body part provides a shock impact to an object. Examples include: using a hand to strike an object.

Repetition is the repeated performance of motion that includes other ergonomic risk factors such as force and/or awkward posture. Severity of the risk increases with higher repetition of motions with ergonomic risk factors.

Static postures occur when a body part is held in a single position over a long period of time. The severity of a static posture can increase if the posture is awkward, applies continual force, and/or is held for long durations. Examples include: sitting or standing in single position for a long duration.

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General Work Practices

Ergonomic risk factors can be controlled by modifying work practices. The following are general principles that should be followed when performing laboratory activities:

  • Alternate between sitting and standing positions;
  • Take frequent micro-breaks every 15-20 minutes;
  • Alternate between work tasks that use different motions and/or body parts;
  • When possible, plan work tasks to include a variety of movements to avoid static postures or repetitive motions;
  • Alternate between using the right and left hands;
  • Alternate grips when performing fine motor tasks (e.g. switching between holding forceps with first and second digits and with thumb and first digit);
  • Avoid contacting or resting wrists or forearms on sharp edges;
  • Arrange work station so that the most often used items are directly in front of the worker (when working inside a fume hood or biosafety cabinet, keep all items at least six inches back from the sash opening to ensure proper airflow into the hood);
  • Maintain proper posture:
  1. Shoulders and neck in a neutral position (i.e. shoulders not raised and neck not bent);
  2. Head upright;
  3. Arms and elbows close to sides;
  4. Wrists in a neutral position (i.e. neither flexed nor extended)
  5. Back straight and upright;
  • When seated, the thighs should be parallel to the floor and feet firmly planted on the floor or on a foot rest;
  • For seated or standing jobs, the work surface and/or chair should be adjusted so that that work can be performed at the following appropriate heights:
  • Precision work: above elbow height;
  • Light work: just below elbow height; and
  • Heavy work: 4-5 inches below elbow height.

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Task-specific Solutions

Workstation design, set up, and tool selection are an important aspect of controlling ergonomic risk factors. When designing a new workstation, follow these general principles:

  • Allow the workstation to be adjusted to the user by selecting adjustable chairs, tables, etc.;
  • Automate processes that involve excessive force and/or high repetition;
  • Select tools that eliminate or reduce the force necessary for gripping, or pinching, and allow the user to maintain neutral positions; and
  • Allow employees to be involved in the workstation design process.

Chairs used inside of laboratories should not have a fabric cover because they are more difficult to decontaminate than non-fabric covered chairs.

The following sections provide solutions for task-specific ergonomic risk factors.

General Bench-top Work

Awkward and static postures are often associated with general laboratory bench-top work, which can result in discomfort in the neck, shoulders, lower back, or legs.

Body Part; Risk Factor; Solutions

Neck and Shoulders

  • Static & Awkward Posture: Storage bins that tilt towards the worker

Lower Back and Legs

  • Standing for long periods: Anti-fatigue mats
  • Seating position: Adjustable stool with built-in footrest

Pipetting

Pipetting can involve prolonged durations of standing or sitting, awkward postures of the shoulders and neck, gripping and pinching, and repetative motion. The general work practice recommendation is to limit pipetting to a total of 4 hours per day and to take short 1-2 minute breaks every 20 minutes.

Body Part; Risk Factor; Solutions

Neck and Shoulders

  • Static & Awkward Posture (arms and elbows elevated “winged” elbows; Neck bent forward): Flexible-arm clamps; Shorter pipetters and pipette tips

Hands and Fingers

  • Repetitive motions: Electronic pipetters; Multi-channel pipetters
  • Pinch grips: Flexible-arm clamps
  • Excessive Force: Electronic pipetters

Lower Back and Legs

  • Standing for long periods: Anti-fatigue mats

Micro-Manipulations and Fine Motor Skills

Micro-manipulations and other tasks requiring fine motor skills involve pinching and gripping, standing or sitting for prolonged durations, awkward postures of the neck and shoulders, and repetative motion.

Body Part; Risk Factor; Solutions

Neck and Shoulders

  • Static & Awkward Posture: Storage bins that tilt towards the worker

Hands and Fingers

  • Repetitive motions: Plastic vials with fewer threads (reduces twisting motions during capping and uncapping)
  • Pinch grips: Flexible-arm clamps
  • Excessive Force: Foam cushioning on forceps and other fine-manipulation tools

Wrists and Forearms

  • Contact Stress: Foam padding on sharp edge; Stage armrests; Pad wrists and forearms

Lower Back and Legs

  • Standing for long periods: Anti-fatigue mats
  • Seating position: Adjustable stool with built-in footrest

Biological Safety Cabinets, Glove Boxes, and Fume Hoods

Working inside of a biosafety cabinet or fume hood can encourage awkward postures when attempting to perform tasks around the sash or over-reaching to access items in the back of the hood. Contact stress of wrists and forearms is also more likely when working inside a biosafety cabinet or fume hood. A glove box requires the user to use more gripping force than normal due overcoming the material of the gloves.

Eye strain is another risk factor associated with using a biosafety cabinet, glove box, or fume hood, because the user is required to look through a glass sash. This risk factor can be controlled by keeping the sash clean and maintaining proper lighting inside the hood.

Body Part; Risk Factor; Solutions

Eyes

  • Eye Strain: Ensure that the sash clean and that there is proper lighting inside the hood; Anti-glare surfaces for sashes

Neck and Shoulders

  • Static and Awkward Postures: Chair that allows adjustment of height and seat pan (select non-fabric covers for safety purposes)
  • Over reaching: Turn tables

Wrists and Forearms

  • Contact Stress: Foam padding on sharp edge of fume hood/BSC; Stage armrests; Pad wrists and forearms

Lower Back and Legs

  • Standing for long periods: Anti-fatigue mats
  • Seating position: Chair that allows adjustment of height and seat pan (select non-fabric covers for safety purposes); Footrests

Microscopy

Using a microscope can be associated with eye strain, awkward and static postures, and contact stress. General work practice solutions include:

  • Take a “20-20-20 Vision Break”: every 20 minutes look approximately 20 feet away for 20 seconds.
  • Ensure scope lenses are clean and the light is set at a proper intensity;
  • Adjust chair height to maintain proper posture and so that the shoulders and neck are in a neutral position (shoulders not raised and neck not bent);
  • Position the microscope as close as possible to maintain the head in an upright position;
  • Avoid contacting or resting the wrists or forearms on sharp edges;
  • Alternate between sitting and standing jobs; and
  • Take frequent micro-breaks every 15-20 minutes.

Body Part; Risk Factor; Solutions

Eyes

  • Eye Strain: Take a “20-20-20 Vision Break”: every 20 minutes look approximately 20 feet away for 20 seconds; Ensure scope lenses are clean and the light is set at a proper intensity; Anti-vibration platforms; Eyepiece-less viewing or video monitor systems

Neck and Shoulders

  • Static and Awkward Posture: Extended eyetube and/or variable height adapter; Adjustable microscope stands; Padded forearm rests; Stage armrests

Wrists and Forearms

  • Contact Stress: Foam padding on sharp edge; Stage armrests; Pad wrists and forearms
  • Awkward & Static Posture: Motorized stage controllers that integrate all X-Y adjustment knobs into on control; Stage armrests

Lower Back and Legs

  • Seating Position: Chair that allows adjustment of height and seat pan (select non-fabric covers for safety purposes); Footrests; Adjustable stool with built-in footrest
  • Standing for long periods: Anti-fatigue mats

Material Handling

Improper lifting techniques can cause back injuries. Back injuries can result from a single improper lift or from minor frequent improper lifts over a time a period. Lifting heavy loads, bending at the waist, and long durations of lifting activities are common risk factors that contribute to back injuries.

When possible, use a hoist or a cart to handle heavy or bulky objects. A hoist is especially recommended when lifting loads from an awkward location, such as lifting rotors from centrifuges. Ask for help when handling heavy or bulky objects if hoists and carts are not available.

Follow proper lifting technique:

  • Stand as close to the object as possible and keep your feet shoulder-width apart;
  • Bend at the knees, not at the waist;
  • Get a good firm grip on the load;
  • Use your legs and not your back to lift the load; and
  • Avoid twisting and awkward movements during the lift.

When transporting load, hold the object close to your body, at the center of your body, and between waist and shoulder height. Avoid twisting your body and pivot with your feet if you need to turn.

Microtome and Cryostat

Turning the cutting wheels of microtomes and cryostats can involve high repetition of forceful exertions. This task can introduce other ergonomic risk factors such as contact stress and awkward postures.

Body Part; Risk Factor; Solutions

Neck and Shoulders

  • Static and Awkward Posture: Padded forearm rests; Stage armrests

Wrists and Forearms

  • Contact Stress: Foam padding on sharp edge; Stage armrests; Padded wrists and forearms rests
  • Awkward Posture: Adjust the feed wheel position to reduce stress
  • Forceful exertions: Select an automatic microtome or use motorized cutting; Reduce force when operating the handwheel; Use foot pedal instead hand-operating cutting wheel

Lower Back and Legs

  • Seating Position: Chair that allows adjustment of height and seat pan; Footrests; Adjustable stool with built-in footrest

Revised:  April 2015

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