ABSTRACT
Of all the building systems, lighting—both daylighting and artificial lighting—is probably the most important from a design point-of-view, simply because excellent lighting can elevate a mediocre design while poor lighting can ruin the finest of designs. The basic measurements for lighting include the lumen, which is a quantity of light (think gallon of water); the candela or candlepower, which is a quantity of intensity (think of water pressure), and footcandle, which is a quantity of density (think of water flow). Humans began using artificial light sources thousands of years ago in the form of fire—wood fires, animal fat fires, and oil fires, among others. Optics for induction lamps vary according to which technology is being used: the Philips QL system or the Osram-Sylvania Icetron system. The induction lamp is either a cathode-less fluorescent lamp or a cathode-less high-intensity discharge (HID) lamp, but the commonality is that there are no electrical components inside the lamp envelope.
