Beam Angle:
The angle, in degrees, between the two opposite directions in which the average intensity is 50% of the center beam intensity as measured in at least two rotational planes, 90° from each other, around and through the beam axis. (ANSI C78.379-2006)
CFL:
See Compact Fluorescent Lamp.
Color Rendering:
Effect of an illuminant on the color appearance of objects by conscious or subconscious comparison with their color appearance under a reference illuminant. (CIE 17.4, ANSI/IES RP-16-10) Color Rendering Index of a Light Source (CRI): The measured degree of color shift objects undergo when illuminated by a light source as compared with the color of those same objects when illuminated by a reference source of comparable color temperature. (10CFR430.2)
Compact Fluorescent Lamp (CFL):
A fluorescent lamp with a small diameter glass tube (T5 or less) that is folded, bent, or bridged to create a long discharge path in a small volume. The lamp design generally includes an amalgam and a cold chamber, or a cold spot to control the mercury vapor pressure and light output (ANSI/IES RP-16-10). For purposes of this specification, compact fluorescent lamps include integral electronic ballasts and are equipped with an ANSI standard base.
Correlated Color Temperature of a Light Source (CCT):
The absolute temperature of a blackbody whose chromaticity most nearly resembles that of the light source. (10CFR430.2)
Covered Lamp:
A lamp with an integral ballast or driver and a translucent envelope over the light source(s). See Envelope.
Decorative Lamp:
A lamp with a candle-like or globe shape envelope including shapes B, BA, C, CA, DC, G and F as defined in ANSI C79.1-2002. For purposes of this specification, lamps with candelabra bases and compact fluorescent lamps with purely decorative outer envelopes including those emulating A shape incandescent bulbs may be tested and evaluated as decorative lamps. Dimmable Lamp: A lamp that is capable of producing varying levels of light when paired with a suitable control. For the purposes of this specification, the lamp must be capable of reducing light output to 20% (or lower) when paired with a control or dimmer while meeting the associated performance requirements in the specification.
Directional Lamp: A
NSI standard PAR and MR lamps having at least 80% light output with a solid angle of π sr, corresponding to a cone with an angle of 120°, self-ballasted compact fluorescent forms that utilize a reflector, and ANSI standard R, BR and ER shapes.
Envelope:
A transparent or translucent enclosure over a light source. An envelope can also consist of a reflector with integral front cover. (Adapted from ANSI C78.357-2010)
FTC:
United States Federal Trade Commission.
Field Angle:
The angle between the two directions for which the intensity is 10% of the maximum intensity as measured in a plane through the nominal beam centerline. (ANSI/IES RP-16-10)
Flicker:
The impression of unsteadiness of visual perception induced by a light stimulus whose luminance or spectral distribution fluctuates with time. (CIE 17.443 e-ILV)
Flicker Index:
A measure of the cyclic variation in output of a light source taking into account the waveform of the light output. It is the ratio of the area under the light output curve that is above the average light output level to the total area under the light output curve for a single cycle. (ANSI/IES RP-16-10)
GU24 Based Integrated Lamp:
A lamp unit that integrates the light source and its ballast or driver. It does not include any replaceable or interchangeable parts, and utilizes the ANSI standardized GU24-base type.
IEC:
International Electrotechnical Commission.
IES:
Illuminating Engineering Society.
Input Power:
The power draw in watts of a ballast or driver and a light source system operating in a normal mode.
Integrated LED Lamp:
An integrated assembly comprised of LED packages (components) or LED arrays (modules), LED driver, ANSI standard base and other optical, thermal, mechanical and electrical components. The device is intended to connect directly to the branch circuit through a corresponding ANSI standard lamp-holder (socket). (ANSI/IES RP-16-10)
Lamp:
A generic term for a man-made source created to produce optical radiation. By extension, the term is also used to denote sources that radiate in regions of the spectrum adjacent to the visible. (ANSI/IES RP-16-10)
LED:
See Light-emitting Diode.
LED Array or Module:
An assembly of LED packages (components) or dies on a printed circuit board or substrate, possibly with optical elements and additional thermal, mechanical, and electrical interfaces that are intended to connect to the load side of a LED driver. Power source and ANSI standard base are not incorporated into the device. The device cannot be connected directly to the branch circuit. (ANSI/IES RP-16-10)
LED Driver Case Temperature Measurement Point (TMPC):
A location on an LED driver case, designated by its manufacturer, which will have the highest temperature of any point on the driver case during normal operation.
LED Package:
An assembly of one or more LED dies that includes wire bond or other type of electrical connections, possibly with an optical element and thermal, mechanical, and electrical interfaces. Power source and ANSI standardized base are not incorporated into the device. The device cannot be connected directly to the branch circuit. (ANSI/IES RP-16-10)
LED Temperature Measurement Point (TMPLED):
A location on an LED package/module/array, designated by its manufacturer, which provides a surrogate temperature measurement location for the actual LED junction. The TMPLED may be a solder joint at the board attachment site, a point on the LED package case, or a location on the board of an LED module or array.
Light-emitting Diode (LED):
A p-n junction solid-state device of which the radiated output, either in the infrared region, the visible region, or the ultraviolet region, is a function of the physical construction, material used, and exciting current of the device. (10CFR430.2)
Lumen Maintenance:
The luminous flux or lumen output at a given time in the life of the lamp and expressed as a percentage of the initial luminous flux or initial lumen output, respectively. (See 10CFR430 Appendix W to Subpart B for lamps covered by the U.S. Department of Energy) Lumen maintenance is the converse of lumen depreciation.
Lumens per Watt (lm/W):
The quotient of the total luminous flux emitted by the total light source power input. It is expressed in lm/W. (Adapted from ANSI/IES RP-16-10: “Luminous Efficacy of a Source of Light”)
MacAdam Color Ellipse:
A space around a chromaticity coordinate that sets the boundary at which a given percentage of people are able to determine that two colors, one with chromaticity coordinates at the center of the ellipse, and one with chromaticity coordinates on the ellipse, are just noticeably different. (Adapted from IES Handbook 10th Edition)
Multi-power Lamp:
A lamp designed to produce multiple discrete light levels when inserted into a lamp socket controlled by a switching mechanism and is designated on the lamp packaging as being a multi-power lamp, e.g. 3-way lamp.
NEMA:
National Electrical Manufacturers Association.
NRTL:
Nationally Recognized Testing Laboratory as recognized by OSHA’s NRTL Program, which is a part of OSHA’s Directorate of Technical Support.
Omnidirectional Lamp:
A general service replacement lamp with an ANSI standard base that emits the majority of light produced in an even distribution. See Luminous Intensity Distribution requirement for omnidirectional lamps. These lamps can be standard; having an ANSI standard lamp shape of A, BT, P, PS, S or T, or non-standard, such as a self-ballasted compact fluorescent that utilizes a bare spiral. OSHA: Occupational Safety & Health Administration.
Percent Flicker:
A relative measure of the cyclic variation in output of a light source (percent modulation). It is given by the expression 100(A-B)/(A+B), where A is the maximum and B is the minimum output during a cycle. (IES RP-16-10)
Periodic Frequency:
The frequency at which the entire periodic flicker waveform pattern repeats.
Power Factor:
The input power in watts divided by the product of RMS input voltage and RMS input current of a ballast or driver.
Rated Lumen Maintenance Life (LP):
The elapsed operating time over which the LED light source will maintain the percentage, p, of its initial light output, e.g., L70 (hours): time to 70% lumen maintenance. (IES LM-80-08)
Rated Wattage:
The wattage marked on the lamp. (10 CFR 430 Appendix W to Subpart B)
Referenced Incandescent Lamp:
A traditional incandescent lamp that predates the federal efficiency standards in the 2007 Energy Independence and Security Act.
Reflector:
A device used to redirect the flux from a source primarily by the process of reflection. (IES RP-16-10)
Run-up Time:
The time between the application of power to the device and the time when the light output first reaches a specified percentage of stable light output, i.e., 80%, 90%, etc.
Secondary Optics:
Materials modifying the distribution of light from, but not integral to a light source, including but not limited to lamp envelopes, reflectors, and total internal reflection optics.
Solid-State Lighting (SSL):
The term “solid-state” refers to the fact that light is emitted from a material by a semiconducting process of electron transition from a conduction band to valence band process whether or not the wavelength of this light is converted by additional components.
Standardized Color Ellipse:
A MacAdam color ellipse defined by center chromaticity coordinates (CIE x, y) and a measure of certainty for detecting a color difference specified in standard deviation units called steps. (ANSI C78.376-2001)
TMPC:
See LED Driver Case Temperature Measurement Point.