Issue 22, April 2007

Good interior lighting is a balance between your occupants' wellbeing, costs, energy consumption, installation and maintenance plus architectural characteristics. Where possible natural daylight should be provided for your occupants.

Your office lighting must facilitate communication, provide suitable directionality to reveal facial expressions and body language, and respond to health and safety considerations, which includes preventing visual discomfort, plus not forgetting the required emergency lighting.

Common problems with artificial lighting include:

• Inadequate lighting design or intensity leading to widespread or localised dark areas described as “gloom”;

• Inappropriate lighting for specialised tasks; i.e. task lighting;

• ‘Flicker’ arising from the oscillation of fluorescent lights typically associated with using magnetic rather than electronic ballasts;

• The colour of the lamp source;

• Poor configuration of lights; and

• Unsympathetic colour schemes which can also contribute to lighting discomfort.

You need to provide appropriate lighting for all the different tasks that are done in your office space.  In your open-plan offices, you probably have many occupants of varying ages, preferences, and abilities doing a large variety of tasks. 

Light levels or illuminance must be selected to match the range of your occupant tasks and both the age and visual characteristics of your occupants.  Small and low-contrast objects require more light for equivalent visibility. More light is also required if your occupants are older or have visual problems.

AS1680: “Interior Lighting” provides guidance for the general principles and recommendations for the lighting of interiors of buildings. If the activities in your office involve both reading and writing tasks, as well as screen based or computer tasks, then light levels should be assessed in both:

• the horizontal plane to characterise the visual task of reading and writing. AS1680 recommends 320 lux minimum for these common office tasks; and

• the vertical plane to characterise screen based tasks. The light reading is taken against the computer monitor. AS1680 recommends 160 lux minimum.

For more information on the interior lighting guidelines for your building you may wish to view AS1680, which includes the  recommended maintenance illuminances for the various types of tasks, activities or interiors.

Cetec can measure your office lighting levels and develop an improvement program to meet your requirements. Next time we will discuss a typical quantitative audit and the importance of the colour rendering of your light source.

Related articles:

Lighting and Productivity
 

Select another article from this issue:

	Green Cities 07: Healthy Buildings = Healthy People
	International Practice for IEQ Management
	Low-VOC Emitting Buildings Products