Just as a workstation or assembly line needs to consider workers of different heights and statures, an office must also consider the individual lighting needs in an office that houses several desks or cubicles. The CSA Z-412 Guideline of Office Ergonomics indicates a target lighting level of 300 to 500lux based on the level of computer use, however variety individual needs and tasks being performed in an open office design require some flexibility.
To give a basic idea of the lighting changes, half of the overhead fixtures had the bulbs removed in a scattered pattern to attempt to distribute the light equally throughout the office while still allowing sufficient lighting at the individual workstations. The window coverings, task lighting and workstation locations did not change.
Light measures were taken on the desk surface between the keyboard and monitor (a primary work point) both before and after the overhead lighting changes with window shades fully open, shaded, or fully closed. Taking the measurements with just the overhead lighting showed a reduction to 290 to 370lux. With the blinds open, the light levels were very high, particularly at the workstations closest to the window. With the blinds shaded, the light levels were lover but not low enough to meet the recommended range.
A survey was also conducted, where the employees were asked some basic demographic information, visual information (use of glasses, light sensitivity) and their level of happiness with the lighting pre and post change. In general, the staff went from somewhat happy/happy to happy and very happy. Some of the concerns noted were 1) the brightness caused by reflection of snow on the ground, 2) brightness of the sunlight and 3) the task lighting is too focused when the overhead lights are off.
So what were the recommendations? Again, taking into consideration the light levels were different depending on the workstation location and individual needs, some of the short term suggestions were:
- Return some of the overhead bulbs to increase light levels at certain workstations.
- Utilize the window shades during periods of the day where it’s brightest or glare from the snow might be a concern.
- Ensure task lighting isn’t shone directly onto monitors or this might produce unwanted glare. When not needed, task lighting should be turned off.
Long term, the consultant recommended replacing the window shades with ones with better control over the amount of lighting entering the office area, but that are not a source of glare itself.
If varying light levels are an issue in your office, give us a call: 780-436-0024.