WORK SURFACES (DESKS)

A work surface can be a desk or part of a workstation. Australian Standard AS/NZS 4442:1997 states the minimum requirements for a work surface as:		  
  • 800 mm deep (14-15" CRT monitors)
  • 1200 mm wide for a single task (e.g. keyboard work only)
  • 1600 mm wide for mixed tasks (e.g. clerical and keyboard work)
  • Work surface height is preferably adjustable:
    • Adjustable including range from 610 to 760 mm
    • Fixed, 700-720 mm preferred but
      can be as low as 680 mm.
  • Legroom width should be a minimum of 650 mm (preferably 800 mm to allow chair to swing both ways)
  • Knee space just under the work surface should be a minimum of 450 mm deep over the whole legroom width
  • Legspace at 120 mm above the floor should be a minimum of 600 mm deep over the whole legroom width.

The minimum depth specified allows monitors to be placed a comfortable distance from the eyes and allows flexibility in the positioning of the keyboard and mouse. Australian Standard AS/NZS 4442:1997 was written in an era where monitors were typically 14"or 15". Bigger monitors often are deeper and a deeper desk should be used (as stated in the standard). The emerging use of flat screens may allow flexibility in the depth of work surfaces.

An adjustable work surface is preferred. Alternatively, a height adjustable footrest will need to be provided for any person who can not place their feet on the floor when the chair is adjusted for the task. Generally, only tall workers will not need a footrest.

The work surface should be thin, light in colour and have a matt finish. A thick desk unnecessarily restricts knee clearances and hence the height adjustment of the chair and leg movements.

  EQUIPMENT PLACEMENT

When laying out the workspace the time spent performing different tasks is important. For example, if a person spends much of their time making phone calls then the telephone keypad should be in the most convenient location. If a CAD operator spends most of the time using the mouse/pointing device then the mouse/pointing device should be in the most convenient location rather than the keyboard.

The most convenient location for the placement of equipment is the area that the hands can reach with the upper arms hanging down freely beside the body - the
'Optimum Reach Zone'. Position frequently used item in this zone. The 'Maximum Reach Zone' is the area that the seated person can reach by extending the arms.
This zone is used for items intermittently placed or retrieved e.g. the telephone for those who receive and make calls intermittently throughout the day. The 'Outer
Reach Zone' is the area that can be reached by bending forward or raising the chair. This area is only suitable for occasional reaches e.g. storage of reference books.

People should be encouraged to adjust the work surface layout as they change tasks. For example, while doingkeyboard work the keyboard should be placed in the
Optimum Reach Zone but it can be stored in the Maximum or Outer Reach Zone while reading or writing.

Work should be designed to provide variety throughout the day. People should stay seated for no longer than one hour at a time.

 
   
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