Lighting for a Benchtop

Calculations

• Different numbers and units describe the amount of light needed for an area or produced by a bulb. Not all numbers are necessarily printed on the light source, so you may have to perform some calculations if you want to compare light output. The most common measurement for lighting in an area is the footcandle, which is equal to the total lumens divided by the area in square feet. Lux represents an international unit of lighting -- equal to one lumen per square meter. One lux equals 1 footcandle multiplied by 10.76, or the total lumens divided by the area in square meters. Lumens describes the amount of light given off by a device and is most often the measurement displayed on bulb packaging.

Guidelines

• The requirements of general ambient lighting can determine whether those who have workbenches can rely on general illumination for their needs. The amount of required lighting varies by room. Recommended levels are 25 footcandles for a bedroom, 35 footcandles for a living room and 50 footcandles for a kitchen or office. The amount of illumination in a bedroom is low because activities such as sleeping or dressing do not involve a lot of detail or safety hazards. Kitchens and offices involve close-in work such as writing, slicing or assembling ingredients. Such activities require twice as much illumination as in the bedroom.

Task Lighting

• Task lighting offers an energy-efficient way of managing illumination because it focuses light in the specific area of the benchtop. It can rely on one bulb with the required lumens instead of several bulbs scattering their lights over a wider area. In general, benchtops and other task areas require at least twice the amount of light as general-use areas. This means, for example, a benchtop in an office or kitchen requires about 100 footcandles of illumination. The amount of area a light can cover depends on its height above the benchtop. As a general rule, a lamp with a typical 30-degree beam spread can cover a maximum surface equal to three times its height above the surface. For example, a downlight mounted at 3 feet above a table can cover 9 square feet. Doubling its mounting height to 6 feet increases its coverage to 18 square feet.

Mountings

• The least obtrusive benchtop light is one that is mounted on the ceiling as a downlight, which generally requires reflector lamps or parabolic light. The method lacks flexibility because the benchtop cannot move away from the light coverage. Table-mounted lamps can move with the benchtop but may take away surface area for tasks. If they have swivels and swing arms, they can pinpoint to particular areas. One way to get the best of both methods is to use a benchtop with a built-in shelf above the main work surface. By mounting the task light on the shelf, you allow the light to move with the bench. This allows you to pinpoint illumination to specific areas and still leave the main surface free for all the work.