Light shelf
A light shelf is a passive architectural device used to reflect natural daylight into a building. 'Bouncing' sunlight off a horizontal surface distributes it more evenly and deeply within a space, whereas direct sunlight can cause glare near an opening, whilst leaving dark areas further in.
Light shelves can be fixed either externally, internally or both (which often works best in providing an even illumination gradient). They are often designed as part of a broader daylight and shading strategy.
They are generally found on walls facing the sun, as on 'pole-facing walls' would tend to act only as sunshades. On east and west orientations, they may act as an effective means of reducing direct heat gain and glare but will not bounce light as deeply into the space.
Exterior light shelves can be more effective than internal light shelves as they do not radiate as much heat into the space and so can help reduce solar heat gain and cooling loads.
Internal light shelves however may be easier to maintain as they can be more accessible and less exposed. In very broad terms, internal light shelves tend to have a depth similar to the height of the opening that they sit below.
Light shelves are commonly made from; timber, glass, plastics, metal panels, plaster, acoustic panels and so on. The choice of material may be determined by considerations regarding the design of the rest of the building, structural strength, ease of maintenance, cost, durability and so on. Opacity is not essential, as some transparency can help more-evenly distribute light.
To be able to reflect light up to the ceiling, the upper surface of light shelves should be matte white or diffusely specular, it does not need to be shiny or reflective. Ideally, the ceiling should also be a light colour.
Light shelves can:
- Enhance daylight quality.
- Reduce the need for artificial lighting and so reduce energy consumption.
- Reduce cooling loads.
- Increase occupant comfort and productivity.
- Enhance design aesthetics.
Some of the limitations or drawbacks of light shelves are as follows:
- They tend to be best-suited to mild rather than tropical or desert climates.
- They can interfere with the installation of sprinkler systems.
- They may require a higher floor-to-ceiling height.
- Their design must be coordinated with windows.
- They Increase maintenance requirements.
Alternative solutions to light shelves include the use of blinds and louvre window systems.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
HAB is a bridge design concept which incorporates an integrated hydraulic system in order to carry more weight.
ICE publish a discussion paper looking at the role of the engineer in creating inclusive cities.
A PQP describes the activities, standards, tools and processes necessary to achieve quality in a project's delivery.
How Lidl has been actively working to reinforce their brand through sustainability.
Association of British Insurers describe full-scale cladding tests as 'utterly inadequate'.
This article examines the changing policy commitments and evolving definitions of the zero carbon home.
Researchers believe they may have created a 'game-changing' new form of concrete using graphene.
Grouting refers to the injection of materials into a soil or rock formation to change its physical characteristics.
Part of Designing Buildings Wiki, BREEAM Wiki will advance knowledge sharing for the BRE family of sustainability tools.
Iron, glass and wood underfoot
From the decorative to the utilitarian, and from the photographed to the forgotten.
New BRE book considers the progression from project-based knowledge creation to whole-life urban knowledge management.
This CIOB article explores the concept of value in building design and construction.