high-bay lighting

[10.3.13] NOTE: This term’s definition was changed in RP-16-17 Addendum 1. Deletions have a strike-through. New text is bold. Interior lighting where the roof trusses or ceiling height is greater than approximately 7.6 6.1 meters (25 20 feet) above the floor. Read More

luminaire efficiency

[9.4.8] NOTE: This term’s definition was changed in RP-16-17 Addendum 1. Deletions have a strike-through. New text is bold. The ratio of luminous flux (lumens) emitted by a luminaire to that emitted by the lamp or lamps used therein. The luminous flux emitted by a luminaire, divided by the luminous flux emitted by the source(s). Sometimes called light output ratio (LOR). Read More

equivalent veiling luminance

[5.9.11.4.2] NOTE: This term was modified in RP-16-17 Addendum 1. The luminance that would need to be superimposed on a scene in object space to reduce the scene’s contrast by an amount equal to the added retinal illuminance from scattered light on the scene’s retinal image. It is most commonly used to describe the contrast-reducing effect of a glare source in the field of view.  Sometimes also called veiling luminance or disability glare. Read More

CIE photopic luminous efficiency function

[3.10.2] V(λ) NOTE: This term and its definition were changed in RP-16-17 Addendum 1. Deletions have a strike-through. New text is bold. Previous name: values of spectral luminous efficiency for photopic vision Values at 10-nm intervals were adopted by the International Commission on Illumination (CIE) in 1924 and by the International Committee for Weights and Measures (CIPM) in 1933 as a basis for the establishment of photometric standards of types of sources differing from the primary standard in spectral distribution… Read More

CIE 1988 2° modified spectral luminous efficiency function for photopic vision

[3.10.2.1] VM(λ) NOTE: This term’s definition was changed in RP-16-17 Addendum 1. Deletions have a strike-through. New text is bold. A luminous efficiency function that closely represents the average color-normal observer based on the Vos modification of Judd’s modification to the V(λ) function. VM(λ) is a supplement to, and not a replacement of, the V(λ) function and differs from V(λ) only at wavelengths below 460 nm* (see Table 13.9). This function principally is of interest in the visual sciences. A supplemental… Read More

CIE scotopic luminous efficiency function

[3.10.3] V’ (Λ) NOTE: This term and its definition were changed in RP-16-17 Addendum 1. Deletions have a strike-through. New text is bold. Previous name: values of spectral luminous efficiency for scotopic vision Values at 10-nm intervals (see Table 13.7) were provisionally adopted by the International Commission on Illumination (CIE) in 1951. Note: These values of spectral luminous efficiency were determined by observation by young dark-adapted observers using extra-foveal vision at near-threshold luminance. The spectral luminous efficiency function for scotopic… Read More

RP-16 Addenda

If you, as a user of ANSI/IES RP-16-17, believe you have located an error not covered by the following revisions, you should e-mail your information to Pat McGillicuddy, pmcgillicuddy@ies.org, or send a letter to Pat McGillicuddy, Manager of Standards Development, IES,120 Wall St., 17th Floor, New York, NY 10005. Additions will be posted as they become available. Addendum 1 for ANSI/IES RP-16-17, Nomenclature and Definitions for Illuminating Engineering Addendum 1 was approved by the IES Standards Committee on March 28,… Read More