Definitions of Common
American National Standards
Average Rated Life
Ballast Factor (BF)
Center Beam Candlepower (CBCP)
Ceramic Metal Halide (CHM®)
Coefficient of Utilization
Color Rendering Index (CRI)
Color Temperature (Correlated Color Temperature -
Compact Fluorescent Lamp (CFL)
Dichroic Reflector (or Filter)
Dimmer, Dimming Control
Distance Between Legs
Distance Between Leg
Distance Outside Legs
Department of Transportation (DOT) Type
Elliptical Reflector (ER) Lamp
Full Spectrum Lighting
High-Intensity Discharge (HID) Lamp
High-Pressure Sodium (HPS) Lamp
Kilowatt Hour (kWh)
Light Center Length (L.C.L.)
Maximum Overall Length (M.O.L.)
Metal Halide Lamp
Power Factor (PF)
- Proforma Invoice
Rated Lamp Life
Reflector Lamp (R)
Sealed Beam Lamp
Single Ended Lamp
Spectral Power Distribution (SPD)
Total Harmonic Distortion (THD)
Ultraviolet (UV) Radiation
Underwriters Laboratories (UL)
Visual Comfort Probability
The general lighting present in an area--excluding task lighting and
accent lighting but including general lighting and daylight streaming
National Standards Institute
(ANSI) Previously ASI
consensus-based organization which coordinates voluntary standards for
the physical, electrical and performance characteristics of lamps,
ballasts, luminaires and other lighting and electrical equipment.
A measure of electrical current. In incandescent lamps, the current is
related to voltage and power as follows: Current (Amps) = Power (Watts)
/ Voltage (Volts).
A three letter
system that has been devised to describe lamps of different manufacture
but the same application. The letters have no relationship to lamp
description, but the same letters always designate the same type of
lamp. Some of the application parameters they define are wattage, base
type, envelope size, maximum overall length, maximum overall diameter
and light center length.
In optics, an aperture is a hole or an opening through which light is
admitted. More specifically, the aperture of an optical system is the
opening that determines the cone angle of a bundle of rays that come to
a focus in the image plane.
light caused by an electrical discharge between two electrodes in a gas
such as xenon, argon, or air. The first usable arc as a practical light
source was developed in 1809 by Sir Humphrey Davy.
auxiliary piece of equipment required to start and to properly control
the flow of current to gas discharge light sources such as fluorescent
and high intensity discharge (HID) lamps.
is the percentage of a lamp's rated lumen output that can be expected
when operated on a specific, commercially available ballast. For
example, a ballast with a ballast factor of 9.93 will result in the
lamp's emitting 93% of its rated lumen output. A ballast with a lower
BF results in less light output and also generally consumes less power.
angular dimension of the cone of light from reflectorized lamps (such
as R, BR, AR and PAR types) encompassing the central part of the beam
the angle where the intensity is 50% of maximum. The beam angle
sometimes called "beam spread" is often part of the ordering code for
reflectorized lamps. Example: The 50PAR30/HIR/NFL25 is a 50 watt PAR30
narrow flood lamp with a beam angle of 25 degrees. See also Field Angle.
- Beam Pattern
complete shape of the beam, as defined in the general sense. It
includes any realistic or abstract patterns introduced into the beam as
well as any apparatus that alters the contour of the beam.
luminaire with a beam whose wavelengths are too short to be visible,
i.e., 320 to 380 nm. These ultraviolet wavelengths excite fluorescent
materials, paints, etc., in theatrical applications.
Operating Position: For good performance, lamps must be used within
specified limitations on operating position. Lamps with plane or flat
mandril filaments should only be inclined perpendicular to the filament
plane. The following abbreviations are used in the lamp descriptions to
indicate these limits:
BD=Base Down. Operate Only Vertical, Base Down
BU=Base Up. Burn Only With the Base Up.
H15=Base Up ±15°
H30=Base Up ±30°
H105=Base Up ±105°
H22=Operate Base Down to 22° Base Up.
HD=Base Down to Horizontal. Do Not Operated Base Above Horizontal
S10=Base Down ±10°
S15=Base Down ±15°
S15/P15=Base Down ±15° or Burn Horizontal ±15°
S20=Base Down ±20°
S20/P20=Base Down ±20° or Burn Horizontal ±20°
S30=Base Down ±30°
S30/P30=Base Down ±30° or Burn Horizontal ±30°
S30/P20=Base Down ±30° or Burn Horizontal ±20°
S45=Base Down ±45°
S100=Base Down ±100°
S105=Base Down ±105°
S120=Base Down ±120°
S135=Base Down ±135°
S90=Base Down ±90°
U=Universal. Operate In Any Position
VBU=Vertical Bulb Up-Base Down
- Candela (cd)
measure of luminous intensity of a source in a given direction. The
term has been retained from the early days of lighting when a standard
candle of a fixed size and composition was defined as producing one
candela in every direction. A plot of intensity versus direction is
called a candela distribution curve and is often provided for
reflectorized lamps and for luminaires with a lamp operating in them.
An obsolete term for luminous intensity; current practice
is to refer to this simply as candelas. See Candela.
Beam Candlepower (CBCP)
to the luminous intensity at the center of the beam of a blown or
pressed reflector lamp (such as a PAR lamp). Measured in candelas. See
also Candela. Also know as MSCP.
Metal Halide (CHM®)
Type of metal halide lamp that uses a ceramic material for the arc tube
instead of glass quartz, resulting in better color rendering (>80
CRI) and improved lumen maintenance.
Construction and Industrial Machinery. CIM is a term for lamps designed
for construction and industrial machinery applications.
general lighting calculations, the fraction of initial lamp lumens that
reach the work plane. CU is a function of luminaire efficiency, room
surface reflectances and room shape.
- Cold Start
term used to describe the ignition of a cold arc lamp, i.e., a lamp
that has not been electrified for a relatively long period of time.
Rendering Index (CRI)
international system used to rate a lamp's ability to render object
colors. The higher the CRI (based upon a 0-100 scale) the richer colors
generally appear. CRI ratings of various lamps may be compared, but a
numerical comparison is only valid if the lamps are close in color
temperature. CRI differences among lamps are not usually significant
(visual to the eye) unless the difference is more than 3-5 points.
Temperature (Correlated Color Temperature - CCT)
number indicating the degree of "yellowness" or "blueness" of a white
light source. Measured in Kelvins, CCT represents the temperature an
incandescent object (like a filament) must reach to mimic the color of
the lamp. Yellowish-white ("warm") sources, like incandescent lamps,
have lower color temperatures in the 2700K - 3000K range; white and
bluish-white ("cool") sources, such as cool white (4100K) and natural
daylight (6500K), have higher color temperatures. The higher the color
temperature the whiter, or bluer, the light will be.
Fluorescent Lamp (CFL)
general term applied to fluorescent lamps that are single-ended and
that have smaller diameter tubes that are bent to form a compact shape.
Some CFLs have integral ballasts and medium or candelabra screw bases
for easy replacement of incandescent lamps. Compact fluorescent lamp
electrical savings are significant. If you pay 10¢ per KWH for your electricity and the typical compact
fluorescent lamp lasts for 10,000 hours the electrical cost for a 27W
compact fluorescent lamp is $27.00 over the life of the lamp. (27W x
10,000H=270,000W/H=270KWH x 10¢ = $27.00). The light output of a
27W lamp is approximately equivalent to a 100W standard household
incandescent lamp. To equal the compact fluorescent lamp for life you
would have to buy ten 1,000 hour light bulbs and it would cost $100.00
for the electricity. The compact fluorescent lamp saves $72.00 in
electricity over the life of the lamp. One disadvantage of the self
ballasted compact fluorescent lamps is that they are not dimmable.
Lighting design for building interiors that makes use of daylight as a
way of reducing energy consumption.
- Daylight Lamp
A lamp resembling the color of daylight, typically with a color
temperature of 5000°K to 6500°K.
- An electric current flowing in one direction only and
substantially constant in value.
Electricity from a battery is direct current.
- To cause a glassy material to become crystalline and
brittle and/or opaque. Fingerprints or grease on the surface of quartz
lamps may cause devitrification of the quartz. It is recommended that
glass surfaces that are subjected to high heat be free of oil and
grease. Devitrification is the act or process of devitrifying, or the
state of being devitrified. Specifically, the conversion of molten
glassy matter into a stony mass by slow cooling, the result being the
formation of crystallites, microbites, etc., in the glassy base, which
are then called devitrification products.
Diamond Precise is the GE trade name for its line-voltage MR16
ConstantColor®halogen lamp. An integral ballast and a medium screw
base enable Diamond Precise lamps to operate on standard (120 volt)
circuits. The MR16 technology of Diamond Precise allows a tighter, more
intense beam than can be attained by the 50-watt PAR20 and R20 types
it's designed to replace, even though the lumen output is significantly
less by comparison.
Reflector (or Filter)
A reflector (or filter) that reflects one region of the spectrum while
allowing the other region(s) to pass through. A reflector lamp with a
dichroic reflector will have a "cool beam" i.e. most of the heat has
been removed from the beam by allowing it to pass through the reflector
while the light has been reflected.
Whether or not the lamp lumens can be varied while maintaining
A device used to lower the light output of a source, usually by
reducing the wattage it is being operated at. Dimming controls are
increasing in popularity as energy conserving devices.
- Distance Between Legs
For U-shaped Fluorescent lamps, this measurement is the average
distance between the inner walls of the legs.
- Distance Between Leg Centers
For U-shaped Fluorescent lamps, this measurement is the average
distance between the centers of each leg.
- Distance Outside Legs
For U-shaped Fluorescent lamps, this measurement is the average
distance to the outside of each leg.
of Transportation (DOT) Type
The US Department of Transportation lamp number stamped in the glass
lens or on the base of headlamps.
Digital Light Processing Technology. DLP is a technology used in
projectors and video projectors. It was originally developed at Texas
Instruments, in 1987 by Dr. Larry Hornbeck. In DLP projectors, the
image is created by microscopically small mirrors laid out in a matrix
on a semiconductor chip, known as a Digital Micromirror Device (DMD).
Each mirror represents one pixel in the projected image. The number of
mirrors corresponds to the resolution of the projected image. 800x600,
1024x768, 1280x720, and 1920x1080 (HDTV) matrices are some common DMD
sizes. These mirrors can be repositioned rapidly to reflect light
either through the lens or on to a heatsink (called a light dump in
Barco terminology). The rapid repositioning of the mirrors (essentially
switching between 'on' and 'off') allows the DMD to vary the intensity
of the light being reflected out through the lens, creating shades of
grey in addition to white (mirror in 'on' position) and black (mirror
in 'off' position).
Light sources where the discharge occurs in a chamber with no
electrodes (no metal.) The energy for the discharge is supplied by
radio frequency excitation, e.g. microwaves (See GENURA).
A continuum of electric and magnetic radiation that can be
characterized by wavelength or frequency. Visible light encompasses a
small part of the electromagnetic spectrum in the region from about 380
nanometers (violet) to 770 nanometers (red) by wavelength.
A short name for a fluorescent high frequency electronic ballast.
Electronic ballasts use solid state electronic components and typically
operate fluorescent lamps at frequencies in the range of 25-35 kHz. The
benefits are: increased lamp efficacy, reduced ballast losses and
lighter, smaller ballasts compared to electromagnetic ballasts.
Electronic ballasts may also be used with HID lamps.
Reflector (ER) Lamp
incandescent lamp with a built-in elliptically-shaped reflecting
surface. This shape produces a focal point directly in front of the
lamp which reduces light absorption in some types of luminaires. It is
particularly effective at increasing the efficiency of baffled
downlights. The shape is rounded like an egg.
- Field Angle
- The angular
dimension of the cone of light from reflectorized lamps (such as R and
PAR types) encompassing the central part of the beam out to the angle
where the intensity is 10% of maximum.
- The wire inside an incandescent lamp envelope that glows
and emits light when heated, i.e., when electricity passes through it.
Filaments are designated by a letter combination in which C is a coiled
wire filament, CC is a coiled wire that is itself wound into a larger
coil, and SR is a straight ribbon filament. Numbers represent the type
of filament-support arrangement.
- Fixture Requirements
- Describes fixture requirements for HID
O = Open or Enclosed Fixtures
E = Enclosed Fixtures Only
S = Lamps operated in a vertical position (Base Up or Down)
±15º, can be used in an open fixture. Lamps burned in any
other orientation must be used in "enclosed fixtures only."
high efficiency lamp utilizing an electric discharge through low
pressure mercury vapor to produce ultra-violet (UV) energy. The UV
excites phosphor materials applied as a thin layer on the inside of a
glass tube which makes up the structure of the lamp. The phosphors
transform the UV to visible light.
unit of illuminance or light falling onto a surface. It stands for the
light level on a surface one foot from a standard candle. One
footcandle is equal to one lumen per square foot. See also Lux.
- Full Spectrum Lighting
marketing term, typically associated with light sources that are
similar to some forms of natural daylight (5000K and above, 90+ CRI),
but sometimes more broadly used for lamps that have a smooth and
continuous color spectrum.
- GE's electrodeless compact fluorescent lamp,
Genura, uses induction to power the
discharge. The chamber generates UV (just like a
discharge in a regular fluorescent lamp) that is converted by phosphors to visible light. Because Genura uses
no electrodes, the life of this unique reflector lamp is longer than
typical compact fluorescent products (See Electrodeless
- A lamp that kills germs, especially pathogenic
microorganisms, like a disinfectant using 254nm ultraviolet radiation
preventing infection by inhibiting the growth or action of
microorganisms. Ultraviolet radiation UV-C is harmful to the skin and
eyes and can cause serious skin burns and eye injury either from direct
or reflected radiation. To reduce the risk of personal injury, install
only in a fixture which provides adequate protection to area occupants.
These lamps SHOULD NOT BE USED FOR ILLUMINATION PURPOSES. You can find
more details on our Germicidal Safety Sheet.
- Visual discomfort caused by excessive brightness is called
discomfort glare. If task performance is affected it is called
disability glare. Glare can be direct glare or indirect (reflected)
glare (See Veiling Reflections and Visual Comfort Probability).
- Halogen Lamp
halogen lamp is an incandescent lamp with a filament that is surrounded
by halogen gases, such as iodine or bromine. Halogen gases allow the
filaments to be operated at higher temperatures and higher efficacies.
The halogen participates in a tungsten transport cycle, returning
tungsten to the filament and prolonging lamp life.
Discharge (HID) Lamp
general term for mercury, metal halide and high-pressure sodium lamps.
HID lamps contain compact arc tubes which enclose various gases and
metal salts operating at relatively high pressures and temperatures.
Sodium (HPS) Lamp
lamps are high intensity discharge light sources that produce light by
an electrical discharge through sodium vapor operating at relatively
high pressures and temperatures.
A term applied to an ignitor that will hot start an arc lamp. Hot
restriking is the restriking of the arc in an HID light source after a
momentary power loss; the lamp restarts when the arc tube has cooled
sufficiently. The restrike time is dependent on the fixture application
as to how long it takes the lamp to cool down to the point of
restarting. This could be anywhere from 5 minutes to 20 minutes or so.
""density"" of light (lumens/area) incident on a surface; i.e. the
light level on a surface. Illuminance is measured in footcandles for
A light source that
generates light utilizing a thin filament wire (usually of tungsten)
heated to white heat by an electric current passing through it.
- Induction Lighting
can be excited directly by radio-frequency or microwaves from a coil
that creates induced electromagnetic fields. This is called induction
lighting and it differs from a conventional discharge, which uses
electrodes to carry current into the arc. Induction lamps have no
electrodes inside the chamber and generally, therefore, have longer
life than standard lamps.
energy radiated in the wavelength range of about 770 to 1,000,000
nanometers. Energy in this range cannot be seen by the human eye, but
can be sensed as heat by the skin.
type of ballast designed to start fluorescent lamps as soon as the
power is applied. Most T8 fluorescent lamps are being operated on
electronic instant-start ballasts. Slimline fluorescent lamps operate
only on instant start circuits.
The International System unit of electrical, mechanical, and thermal
energy. A unit of electrical energy equal to the work done when a
current of one ampere is passed through a resistance of one ohm for one
second. A unit of energy equal to the work done when a force of
one newton acts through a distance of one meter.
A measure of electrical power equal to 1000 watts.
standard measure of electrical energy and the typical billing unit used
by electrical utilities for electricity use. A 100-watt lamp operated
for 10 hours consumes 1000 watt-hours (100 x 10) or one kilowatt-hour.
If the utility charges $.10/kWh, then the electricity cost for the 10
hours of operation would be 10 cents (1 x $.10).
term used to refer to the complete light source package, including the
inner parts as well as the outer bulb or tube. "Lamp", of course, is
also commonly used to refer to a type of small light fixture such as a
The electrical device
that supports a lamp in a luminaire, and generally contains the
contacts that make the electrical connection to the contacts of the
Liquid-Crystal Display: a method of displaying readings continuously,
as on digital watches, portable computers, and calculators, using a
liquid-crystal film, sealed between glass plates, that changes its
optical properties when a voltage is applied. LCD (liquid crystal
display) projectors usually contain three separate LCD panels, one each
for the red, green, and blue components of the video signal. However
single panel LCD projectors have been produced in the past. Light from
a lamp is split by a prism into the three component colors. These lamps
also have the ability to produce an extremely large amount of light
within a small area, on average for current projectors of 2,000-4,000
ANSI Lumens. As light passes through the LCD panels, individual pixels
can be opened to allow light to pass, or closed to block the light, as
if each little pixel were fitted with a Venetian blind. This activity
modulates the light and produces the image that is projected onto the
screen by allowing many different shades from each color LCD panel.
Light-Emitting Diode: a semiconductor diode that emits light when
conducting current and is used in electronic equipment. The
semiconductor diode converts applied voltage to light and is
used in digital displays such as calculator, digital watch, etc.
See Rated Lamp Life.
Radiant energy that can be sensed or seen by the human
Visible light is measured in lumens.
Center Length (L.C.L.)
The distance between the center of the filament, or arc
tube, and a reference plane - usually the bottom of the lamp base.
measure of luminous flux or quantity of light emitted by a source. For
example, a dinner candle provides about 12 lumens. A 60-watt Soft White
incandescent lamp provides 840 lumens. Electric Light Inside.
measure of how well a lamp maintains its light output over time. It may
be expressed numerically or as a graph of light output vs. time.
complete lighting unit consisting of a lamp (or lamps), ballast (or
ballasts) as required together with the parts designed to distribute
the light, position and protect the lamps and connect them to the power
supply. A luminaire is often referred to as a fixture.
A photometric measure of "brightness" of a surface as
by the observer, measured in candelas per square meter.
The ratio of total lumens emitted by a luminaire to those
emitted by the lamp or lamps used in that luminaire.
light output (lumens) of a light source divided by the total power
input (watts) to that source. It is expressed in lumens per watt.
- Lux (lx)
unit of illuminance or light falling onto a surface. One lux is equal
to one lumen per square meter. Ten lux approximately equals one
footcandle. See also Footcandle. This is
often referred to as center beam candle power or CBCP.
A metal rod or bar around which material, such as metal
glass, may be shaped.
Overall Length (M.O.L.)
The end-to-end measurement of a lamp, expressed in inches
average light output of a lamp over its rated life. Based on the shape
of the lumen depreciation curve, for fluorescent and metal halide
lamps, mean lumens are measured at 40% of rated lamp life. For mercury,
high pressure sodium and incandescent lamps, mean lumen ratings refer
to lumens at 50% of rated lamp life. See Lumen
Maintenance. Or possibly lumens that are not very nice, I am not
high-intensity discharge light source operating at a relatively high
pressure (about 1 atmosphere) and temperature in which most of the
light is produced by radiation from excited mercury vapor. Phosphor
coatings on some lamp types add additional light and improve color
discharge light source in which the light is produced by the radiation
from mercury, plus halides of metals such as sodium, scandium, indiu,
and dysprosium. Some lamp types may also utilize phosphor coatings.
Relating to or made by a micrometer. Micrometry is the measurement of
minute objects with a micrometer. A micrometer is a device for
measuring very small distances, objects, or angles, especially one
based on the rotation of a finely threaded screw, as in relation to a
A unit of wavelength equal to one billionth of a meter.
A unit of electrical resistance equal to that of a conductor in which a
current of one ampere is produced by a potential of one volt across its
terminals. A unit of electrical resistance equal to the resistance
between two points on a conductor when a potential difference of one
volt between them produces a current of one ampere.
is an acronym for parabolic aluminized reflector. A PAR lamp, which may
utilize either an incandescent filament, a halogen filament tube or a
HID arc tube, in a precision pressed-glass reflector lamp. PAR lamps
rely on both the internal reflector and prisms in the lens for the
control of the light beam.
inorganic chemical compound processed into a powder and deposited on
the inner glass surface of fluorescent tubes and some mercury and
metal-halide lamp bulbs. Phosphors are designed to absorb short
wavelength ultraviolet radiation and to transform and emit it as
A measure of
the phase difference between voltage and current drawn by an electrical
device, such as a ballast or motor. Power factors can range from 0 to
1.0 with 1.0 being ideal. Power factor is sometimes expressed as a
percent. Incandescent lamps have power factors close to 1.0 because
they are simple "resistive" loads. The power factor of a fluorescent
and HID lamp system is determined by the ballast used. "High" power
factor usually means a rating of 0.9 or greater. Power companies may
penalize users for using low power factor devices.
type of fluorescent lamp-ballast circuit used with the first commercial
fluorescent lamp products. A push button or automatic switch is used to
preheat the lamp cathodes to a glow state. Starting the lamp can then
be accomplished using simple "choke" or reactor ballasts.
A quotation in the form of an invoice prepared by the seller that
details items which would appear on a commercial invoice if an order
results. An invoice sent in advance of shipment, usually to enable the
buyer to obtain an import permit or foreign exchange permit, or both.
The proforma invoice gives a close approximation of the weights and
values of the shipment to be made.
Quartz is a very hard crystalline form of silicon dioxide used in
chemical apparatus and in optical and electric instruments. Quartz is
used to make a colorless glass made of almost pure silica. A clear
vitreous solid, formed by melting pure quartz, that can withstand high
temperatures and is extremely transparent to infrared, visible, and
ultraviolet radiations. Also called fused quartz or fused silica.
Quartz glass is often combined with halogen gas for smaller lamps that
withstand higher heat. A halogen lamp is an incandescent lamp
with a filament that is surrounded by halogen gases, such as iodine or
bromine. Halogen gases allow the filaments to be operated at higher
temperatures and higher efficacies. The halogen participates in a
tungsten transport cycle, returning tungsten to the filament and
prolonging lamp life.
- Rapid Start Circuit
fluorescent lamp-ballast circuit that utilizes continuous cathode
heating, while the system is energized, to start and maintain lamp
light output at efficient levels. Rapid start ballasts may be either
electromagnetic, electronic or of hybrid design. Full-range fluorescent
lamp dimming is only possible with rapid start systems.
most lamp types, rated lamp life is the length of time of a
statistically large sample between first use and the point when 50% of
the lamps have died. It is possible to define "useful life" of a lamp
based on practical considerations involving lumen depreciation and
color shift. The average rated life for a lamp is calculated by burning
a group of lamps at the perfect rated voltage. The point at which half
of the lamps are out and half are burning is the average rated life.
Your actual life will vary greatly based on how you use the lamp. Lamp
handling, voltage applied, use cycles and environment are all factors
that alter your actual lamp life. Generally, manufacturers only
warranty against defects in manufacturing.
A light source
with a built-in reflecting surface. Sometimes, the term is used to
refer specifically to blown bulbs like the "R" and "ER" lamps; at other
times, it includes all reflectorized lamps like PAR and MR.
The RoHS Directive stands for "the restriction of the use of certain
hazardous substances in electrical and electronic equipment".
This Directive bans the placing on the EU market of new electrical and
electronic equipment containing more than agreed levels of lead,
cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB)
and polybrominated diphenyl ether (PBDE) flame retardants.
measurement accounts for the fact that of the two light sensors in the
retina, rods are more sensitive to blue light (Scotopic vision) and
cones to yellow light (Photopic vision). The Scotopic/Photopic (S/P)
Ratio is an attempt to capture the relative strengths of these two
responses. S/P is calculated as the ratio of scotopic lumens to
photopic lumens for the light source on an ANSI reference ballast.
Cooler sources (higher color temperatures lamps) tend to have higher
values of the S/P Ratio compared to warm sources.
A lamp with an integral light source, reflector, and
all of which are either sealed within, or are a part of the envelope.
A lamp that has only one base and all of its contacts on
- Skirted Base
A protective sleeve that extends beyond the base of the lamp over the glass of the lamp. The purpose of the skirt is to provide more holding area to better attach the lamp to the base. This is important in some base up operations where a lot of heat can affect the ceramics attaching to the base and glass. Skirting can also help support heavier glass styles like PAR lamps for example. Modern ceramics withstand more heat and so skirting is less important with newer lamps.
Power Distribution (SPD)
graph of the radiant power emitted by a light source as a function of
wavelength. SPD's provide a visual profile of "finger print" of the
color characteristics of the source throughout the visible part of the
(Turn and Lock)
TAL lamps have a twin post base that you insert and turn to lock into
position. These are sometimes also referred to as Twist and Lock type
lamps. These MR16 halogen dichroic lamps have a cover glass and a
varitey of beam spreads. The following chart shows the lamp options
available. The narrow beam lamps have a trapezoidal faceted mirror
reflector and these include the 414, 417, 420 and 424. The remainder of
the medium and wide flood beam spreads have honeycomb mirror reflectors
|Lux at 1M
|Lux at 2M
|Lux at 3M
|Lux at 4M
||Lux at 5M
The Toxicity Characteristic Leaching Procedure (TCLP) test, specified
in the Resource Conservation and Recovery Act (RCRA) of 1990, is used
to characterize fluorescent lamp waste as hazardous or nonhazardous
waste. The TCLP test measures the ability of the mercury and/or lead in
a lamp to leach from a landfill into groudwater.
Teflon is a registered trademark for Dupont. Teflon is a trade name for
a solid, chemically inert polymer of tetrafluoroethylene (C2F4),
F2C[dbond]CF2. Stable up to temperatures around 572°F (300°C),
Teflon is used in electrical insulation, gaskets, and in making
low-adhesion surfaces, e.g., for nonstick cookware. In the lighting
industry teflon is used to coat lamps to prevent the glass from
breaking and to hold the glass together should it break. Often Teflon
is used to tough coat lamps for construction applications and resists
thermal shock breakage from inclement weather when water, sleet or snow
come in contact with the lamp. Certain lamps like the GBF and 1383 are
used in elevators with Teflon
coating.. In food applications Teflon helps prevent glass from getting
into food or hitting people should a lamp break.
Harmonic Distortion (THD)
A measure of the distortion of the input current on alternating current
(AC) power systems caused by higher order harmonics of the fundamental
frequency (60Hz in North America). THD is expressed in percent and may
refer to individual electrical loads (such as ballast) or a total
electrical circuit or system in a building. ANSI C82.77 recommends THD
not exceed 32% for individual commercial electronic ballasts, although
some electrical utilities may require lower THDs on some systems.
Excessive THDs on electrical systems can cause efficiency losses as
well as overheating and deterioration of system componenets.
Radiant energy in the range of about 100-380 nanometers (nm). For
practical applications, the UV band is broken down further as follows:
• Ozone-producing — 180-220nm
• Bactericidal (germicidal) — 220-300nm
• Erythemal (skin reddening) — 280-320nm
• "Black" light — 320-400nm
The International Commission on Illumination, CIE, defines the UV band
as UV-A (black light) 315-400nm; UV-B 280-315nm and UV-C (germicidal)
- A UV-A ultraviolet black light is a lamp that emits long
wave UV radiation and very little visible light. Fluorescent black
lights are typically made in the same fashion as normal fluorescent
lights except that only one phosphor is used and the normally clear
glass envelope of the bulb may be replaced by a deep-bluish-purple
nickel-oxide–doped glass which blocks almost all visible light above
400 nanometers. The color of these lamps is referred to as "blacklight
blue" or "BLB." This is to distinguish these lamps from "bug zapper"
blacklight ("BL") lamps that don't have the blue glass. These lamps
output at 354nm.
- The name ultraviolet means "beyond violet" from Latin
ultra, "beyond", violet being the color of the shortest wavelengths of
visible light. UV light has a shorter wavelength than that of violet
private organization which tests and lists electrical (and other)
equipment for electrical and fire safety according to recognized UL and
other standards. A UL listing in not an indication of overall
performance. Lamps are not UL listed except for compact fluorescent
lamp assemblies - those with screw bases and built-in ballasts and LED products because of the required electrical components. UL registered products are UL Listed or UL Recognized. UL Listed means the product has been tested and meets standards. UL Recognized applies to components that meet applicable standards but they may need to be incorporated in specific ways in order to be safely used.
- Veiling Reflections
- Veiling reflections are specular reflections superimposed
upon diffuse reflections from an object that partially or totally
obscures visual details by reducing luminance contrast and therefore
visibility. The facets of "glossiness" inherent in almost all objects
are too small to be visible to the naked eye, although they can be seen
under a suitable microscope. Nevertheless, the macroscopic effect,
called reflected glare, can be experienced directly by anyone who
attempts to read a glossy magazine while facing a window on a bright,
sunny day. The image of the sun and sky is reflected as a veil of light
directly into the observer's eyes, reducing contrast and therefore also
- In practice, veiling reflections may be minimized by
overhead luminaires (or employing ones with appropriate intensity
distributions) in such a way that most of the light passes in front of
and across the observer, perpendicular to the direction in which he
faces, so minimizing specular reflections in the direction of view.
This can also be achieved by employing multi-layer polarizing panels in
luminaires that produce vertically polarized light. Veiling reflections
are one of the most important factors affecting lighting quality; a
non-uniform luminance distribution surrounding the visual task is
another, but less significant.
A rating system for evaluating direct discomfort glare, expressed as
the percent of occupants of a space who will be bothered by direct
glare. VCP takes into account luminaire luminance at different angles
of view, luminaire size, room size, luminaire mounting height,
illuminance and room surface reflectiveness.
measurement of the electromotive force in an electrical circuit or
device expressed in volts. Voltage can be thought of as being analogous
to the pressure in a waterline. Orthodox Static Pressure
A unit of electrical power. Lamps are rated in watts to
indicate the rate at which they consume energy. See Kilowatt Hour.
Consuming War Potential.
A xenon lamp is a light source containing xenon gas; often operated as
a pulsed light source, as in a strobe lamp. The addition of xenon gas
into the glass envelope of a lamp increases the rated life of the lamp.
Depending on the lamp the average rated life is somewhere between 8,000
and 20,000 hours. Xenon lamps run cooler than the line voltage halogen
lamps and xenon lamps are dimmable in non-pulsed applications. Xenon
lamps have a Color Temperature that is between
ordinary incandescent and halogen. That is, the light is cooler in
appearance than incandescent but warmer in appearance than halogen.
- Yard Lighting
- Outdoor lighting fixtures, including hanging pendant lamps,
wall lights, security lights and landscape lighting used to beautify
and enhance an outdoor space.
In dimming, lights that are operated together. Also called Channel
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