Environmental Health & Safety

Workstation Configuration

The workstation should be configured to support neutral body positioning. The following steps will help to ensure the operator can work from a relaxed posture. To begin, several measurements of the operator are needed. Guidelines will then be used to configure the workstation to fit the parameters of the operator.

1. Standing Knee Height: With the operator standing, measure from the floor to the upper edge of the operator's kneecap. This will determine the height range of the task chair seat pan necessary to support the operator in a declined (forward-tilt) configuration. If the chair does not feature a forward-tilting seat pan, then make sure that the seat pan height range will allow the operator to sit with their legs parallel to the floor.

2. Popliteal-Buttock Length: With the operator seated, measure from the back of their knee to their buttock. This will be used to determine the proper seat pan depth of the chair which should provide a comfortable space between the front of the seat pan and the back of the operator's knee. The seat pan depth should not exceed the popliteal-buttock length of the operator, though it can can be up to two inches shorter. It is important to ensure that the seat pan of the chair does not press against the back of the operator's knee.

3. Resting Elbow Height: With the operator comfortably seated in their preferred sitting posture, have them relax their shoulders and hang their arms at their sides, then bend one elbow ninety degrees. Measure from the floor to their elbow.This will be used to determine the height of the operator's work surface.

4. Sitting Eyebrow Height: With the operator comfortably seated, measure from the floor to the operator's eyebrow. This will be used to determine the height of the operator's monitor.

Having taken the necessary anthropometric measurements of the operator, the workstation can be properly configured as explained below. These are guidelines only and there are exceptions. The objective is to facilitate a comfortable posture. If there are concerns that this guideline is not sufficient on an individual basis, contact Environmental Health and Safety for assistance.

1. The operator is sitting comfortably with their feet resting on the floor.


2. The work surface is set to within one inch of the height of the operator's resting elbow height. If the work surface cannot be lowered to a comfortable height with respect to the operator, measures may be taken to raise the operator with respect to the work surface.
   
   The sitting posture and type of chair should be taken into consideration here. If the operator prefers the declined posture, as shown in figure 2, this is likely to result in a higher resting elbow height than if the operator prefers the reclined or upright postures.


3. The monitor is placed as far from the operator as possible with the operator still able to read it clearly without affecting their posture. This is because longer distances relax the eyes. The height of the monitor should promote a comfortable posture of the head and neck. A good starting point is to place the upper edge of the display within an inch of the operator's sitting eyebrow height. This should bring their natural line of sight to fall on the the lower part of the upper third of the display. If the operator feels that they are holding their head and neck extended backward or flexed forward to view their display, the monitor should be lowered or raised accordingly. People who wear bifocals will likely need to have their monitor set lower. If the operator uses eyewear at their workstation, they should consider consulting with their medical care provider about eyewear specific for use at a video display terminal.


4. If the operator frequently transfers information from documents to their computer, placing a copyholder in line with their display can reduce strain associated with flexing or twisting their head and neck.


5. An appropriate adjustable keyboard tray with a negative tilt feature can be used to optimize the position of the mouse and keyboard, further reducing strain. If moderate computer use is required of the operator for more than four hours per day, and the operator is a touch typist, an adjustable keyboard tray is recommended.


6. The operator should have adequate clearance beneath their work surface to be able to move freely and avoid awkward postures.

Not Shown

• To further avoid awkward postures, everything that is used frequently should be within an easy reach.


• The majority of the operator's work should also be placed in front of their midline. This helps to avoid having to twist the upper body while working. For jobs that require customer service and computer use, the position of the display should be close to the position of the customer. This will help to minimize twisting as the operator shifts between the customer and their computer terminal.

Fig. 3. Workstation Configuration for the reclined posture.

• For seating options which do not rely on the forward tilt posture to maintain comfort, the workstation will have a similar configuration. It is important to verify the work surface and display heights support a comfortable posture.