Architectural light shelf

A light shelf is an architectural element that allows daylight to penetrate deep into a building. This horizontal light-reflecting overhang is placed above eye-level and has a high-reflectance upper surface. This surface is then used to reflect daylight onto the ceiling and deeper into a space. Light shelves are generally made of an extruded aluminium chassis system and aluminium composite panel surfaces. Extruded components can be painted or anodized and they are all field fabricated and assembled from stock lengths.

Light shelves are typically used in high-rise and low-rise office buildings, as well as institutional buildings. This design is generally used on the southern side of the building, which is where maximum sunlight is found, and as a result is most effective. Not only do light shelves allow light to penetrate through the building, they are also designed to shade near the windows, due to the overhang of the shelf, and help reduce window glare. Exterior shelves are generally more effective shading devices than interior shelves. A combination of exterior and interior shelves will work best in providing an even illumination gradient. For maximum benefit, perimeter lighting should be controlled by photo-sensors, with lighting zones appropriate to the particular installation

Benefits

Architectural light shelves have been proven to reduce the amount of artificial lighting in a building. Since they can reflect light deeper into a space, the use of incandescent and fluorescent lighting can be reduced or completely eliminated, depending on the space. Light shelves make it possible for daylight to penetrate the space up to 2.5 times the distance between the floor and the top of the window. Today, advanced light shelf technology makes it possible to increase the distance up to 4 times. In spaces such as classrooms and offices, light shelves have been proven to increase occupant comfort and productivity. Furthermore, incorporating light shelves in a building design is admissible for the LEED point system, falling under the “Indoor Environment Quality: Daylight & Views” category.

Aesthetics

Light shelves integrate themselves with window designs or curtain wall systems which make them aesthetically pleasing. They are made of very light materials which make them visible but not distracting. The aluminium composite panel surfaces can be painted or anodized, and can be ordered in various colours. Two options are available, the fascia cap and the continuous panel

Limitations

Although light shelves are a very good design element, they may not be suitable for all climates. They are generally used in continental climates and not in tropical or desert climates due to the intense solar heat gain. These hot climates, compared to continental climates, have very small window openings to reduce the amount of heat infiltration. In Canada, they are installed in buildings with sprinkler systems and they cannot exceed 1200 mm (4ft.) in width or the design will require integration with sprinkler system to cover the floor area under the light shelf area. They also require higher than average floor-to-ceiling heights in order for them to be effective. An average floor-to-ceiling height would be approximately 3m (9.8 ft.). Light shelves are not necessarily suitable for all building projects. Their use depends on such factors like the building form, orientation, window sizes etc. The only disadvantages are that they slightly increase maintenance requirements and the window coverings must be coordinated with light shelf design.

With today’s development of Green Architecture, there is no limit to where light shelves can be used. 21st century Architects have designed residential homes using light shelves, giving them a modern appeal and increasing energy savings. (P.O.P)

ee also

* Daylighting