Natural Resources Canada
Symbol of the Government of Canada

Office of Energy Efficiency Links


Business: Industrial

Lighting Reference Guide – Bibliography

17 Bibliography

  • Lighting Reference Guide, Seventh Revision, January 2002
  • Rae, Mark S., ed. The IESNA Lighting Handbook, Reference & Application, 9th edition, New York, NY, IESNA 2000
  • General Electric Catalogues.
  • Philips Lighting Catalogues.
  • OSRAM/Sylvania Lighting Catalogues.


18 Glossary of Terms


– a device used with a gas discharge lamp to provide the necessary starting and operating electrical conditions.

candela (cd)

– the fundamental unit from which all other lighting units are derived. Candlepower, the intensity of light in a specified direction, is measured in candelas. An ordinary wax candle has a candlepower of about one candela.

– candelas are used to compare intensities of different kinds of directional light sources. In a 75 W spotlight lamp the centre of beam is 1,730 candelas and in a 75 W floodlight lamp it is 430 candelas, i.e., the centre of the spotlight’s beam is four times as intense as the floodlight’s.


– a device commonly put on the bottom and/or sides of a luminaire to redirect or scatter the light from a source.


– the scattering of light that falls on a surface.


– the ratio of total lumens produced by the light source to the watts consumed by the source, expressed in lumens per watt.


– the ratio of the total lumens emitted by the luminaire to those emitted by the lamp, expressed as a percentage.

electromagnetic spectrum

– the total range of wavelengths of frequencies of electro magnetic radiation. The visible portion covers a wavelength from approximately 380 nm to 780 nm (1 nm = 10-9m).

foot candle (fc)

– the practical working unit for the measurement of lighting level equal to one lumen falling uniformly on an area of one square foot.


– luminous flux density or lumens per unit area incident on a surface. The unit of illuminance is the lux (lx) where

   1 lx = 1 lm/m2 (SI units) or the foot candle (fc) where
   1 fc = 1 lm/ft2 (Imperial units). The relationship between lux and foot candle
    is 1 fc = 10.76 lx.

Illuminating Engineering Society of North America

– the recognized technical authority in the illumination field in North America.


– a generic term for an electric source of light. A lamp usually consists of a light–generating element (arc tube or filament), support hardware, enclosing envelope and base.


– any radiation which makes things visible. It is radiant electromagnetic energy capable of exciting the retina of the eye and producing a visual sensation.

lumen (lm)

– the unit of luminous flux, i.e., the quantity of light emitted by a lamp. 1 lumen = 1 candela, × 1 steradian.


– a complete lighting unit consisting of a lamp(s) and parts designed to distribute the light, to position and protect the lamp(s) and to connect the lamp(s) to the power supply.


– the luminous intensity of a surface in a given direction per unit of projected area. The unit for luminance is NIT = candela/m2 or foot–lambert = π candela/ft2. A surface emitting or reflecting light in a given direction at a rate of one candela per square meter of projected area has a luminance in that direction of 1 cd/m2 or 1 NIT.

luminous exitance

– the light leaving a surface at a point is measured in lumens per square foot.

lux (lx)

– a unit of illuminance or lighting level equal to one lumen uniformly falling on an area of one square meter.

photometer (light meter)

– an instrument for measuring photometric quantities such as illuminance (in foot candles or lux). The light sensitive cell, typically a selenium cell, must be cosine corrected and Vλ corrected.


– the ratio of light emitted from a surface to the light falling on that surface.


– the bending of light rays as they pass through clear glass or plastic.

specular surfaces

– surfaces from which the reflection is predominantly regular, e.g., highly polished or mirror finished surfaces.


– the ratio of light transmitted through a light–passing material e.g. glass or ceramics to the incident light falling on that material.

Previous Page | Table of Contents