Bulbs and Tubes

As part of the electricity system delivering artificial light to the interior and exterior of buildings, bulbs and tubes are replaceable components that are fitted into light fittings. The size and lighting capacity of bulbs and tubes vary in strength and how much light they cast. Light bulbs come in a variety of types. Incandescent bulbs have a filament, often made of tungsten, set in a vacuum or inert gas. Halogen bulbs are more efficient whilst gas discharge bulbs include fluorescent light. They are being replaced by compact fluorescent light (or CFL). Light-emitting diodes (or LED) are now also being used for bulbs. Tubes can trap both natural and artificial light for distribution purposes. One type of tube is a light bulb with reflective material, which leads light through a roof structure. Optical fibre tubes use a parabolic collector to track the sun. Other categories of tubes are transparent hollow light guides and fluorescent-based systems, which capture ultraviolet light. Light bulbs and tubes are found in any building to ensure the correct amount of illumination. The unique properties of tubes mean they are more likely to be found in larger commercial buildings since they can concentrate natural light.