Lighting A to Z

GlossaryBritish Thermal Units (BTUs) Measurement of heatproduced Unit BTU, BTUs per hour = Watts X 3.413Bulb The glass outer or envelope of a lamp. Also, a lamp iscommonly referred to as a bulb.Burning Position The position in which a lamp is designed tobe operated.Canadian Standards Association (CSA) Anorganization that writes standards and tests lighting equipmentfor performance as well as electrical and fire safety. Canadianprovincial laws generally require that all products sold forconsumer use in Canada must have CSA or equivalent approval.Candela The unit of measure for intensity in a given direction.The term has been retained from the early days of lighting whena standard candle of a fixed size and composition was used as abasis for evaluating the intensity of other light sources.Candlepower (CP) The intensity or the strength of thebeam in a given direction. Unit candela, cd.Chromaticity See color temperature.Class “P” Ballast Contains a thermal protective device,which deactivates the ballast when the case reaches a certaincritical temperature. The device resets automatically when thecase temperature drops to a lower temperature.Color Appearance The color impression when lookingdirectly at a light source.Color Rendering Expression for the effect that the light hason the color appearance of objects.Color Rendering Index (CRI) of a light sourceA scale from 0–100 that describes how natural the color ofobjects will appear as compared to a standard light source (100CRI). The standard light sources are Incandescent/Halogen bulbs(100 CRI) for warm sources and Natural Daylight (100 CRI) forcool sources.Color Temperature A term used to describe the“whiteness” of light. It is the temperature of a piece of metal(or black body) that emits the same color light as the comparedlight source. Unit Kelvin, K.44 Product Knowledge