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Too much or too little light?

Too much light?

Lighting schemes for offices need to meet the lux level standard throughout the year (during the day and night hours). Lighting schemes at the University of Warwick will have been designed to meet the guidance standard at the time that the space was designed. Over the years the required lux levels have not altered for office spaces. The only change in the recent guidance document is that lighting schemes may now have to accommodate a change in technology or change in the way in which we use our spaces (to accommodate hot-desking as an example, or predominant requirement for touchscreen/tablet use). Only when spaces are being used in this way should there be a need to reduce the lighting level or look at a change to the lighting scheme.

Where there is excessive level of daylight, particularly on sunny days, this is relatively easy to control by the use of translucent or vertical blinds (the latter is preferable as it permits someone working at a computer to view through them whilst removing the excess light); this can also reduce solar gain in a building during the summer months.

Other methods to alter the amount of reflection experienced from daylight when working at your desk can be found on the Work Environment page of the Computer Work pages. This includes recommending changes to the furniture layout of the workplace to reduce shadowing, reflections and glare. IT Services should be contacted if you wish to change the contrast on your computer from the set default to reduce the light being reflected back at you from your screen (for IT Services managed computers) or to increase the contrast between background colour and text colour. There is also an anti-glare screen mount that can be clamped onto a desk that can help to remove overhead glare for those who are particularly sensitive to light.

The wall, ceiling and floor finishes can also have a dramatic effect on the transfer of light through a room, with a room with darker walls, or with dark coloured furniture reducing the amount of light transferred within a room from the window.

The removal of single bulbs in a large office space can have a dramatic impact on the amount of light distributed throughout an office area and can result in a reduction in lux levels to below the required standard. As a consequence removal of individual lights in a lighting scheme is not generally accepted as a solution to an individual preference. Should individuals experience too much light for working at their computer, reference should first be made to the guidance for setting up your computer workspace for further advice and support, including information for those that suffer headaches and migraine.

Too little light?

Designers should make as much use of daylight as possible to meet the recommended level of illumination of an office space. Where this is not possible, due to the location or depth of the room, the level of illumination should be made up of artificial light, such that it meets the accepted level of illumination as stated in Lighting Guidance for Offices. The colour of walls and furniture can make a difference in light transfer within a room. A dimly naturally lit space would thus benefit from light coloured furniture and surface finishes.

Use of daylight bulbs are not considered important within CIBSE Guidance Note 7. In fact, these are only referenced where colour-critical activities such as printing is being carried out, where colour rendering may be an important operational need, and even then, it is stated that there is a popular misconception that using lamps that mimic the colour of daylight will support colour correctness (colour rendering), when actually this is NOT the case. Reflected light from coloured walls, ceilings, floors, furniture and equipment will all affect colour rendering and should be considered as opposed to swapping over bulbs for daylight bulbs.

'Seasonal Affective Disorder (SAD)' bulbs used for light therapy are not recommended for office use.