Explanations of Common Lighting Related Terms:
ANSI: This references the part # on a lamp EXN, FCL, etc.
The "ANSI CODE" is actually a reference code created by the
American National Standards Institute that correspond to
certain guidelines to help ensure that lamps, as well as
many other items meet certain performance standards.
BALLAST: A ballast is a device (transformer) used to transform
the line voltage as necessary to meet the requirements of a specific
lamp. They are most commonly used with fluorescent and HID
lamps such as HPS and Metal Halide and Mercury Vapor.
BALLAST FACTOR: The ability of a ballast to produce light from
a certain lamp. A .9 BF would provide a 90% light output as compared
with a standard lamp and reference ballast. A 1.15 BF would be 115%.
COLOR RENDERING INDEX (CRI): CRI indicates the quality of
light produced by a lamp. The higher the "CRI" to a maximum of 100
(sunlight is 100 CRI), the more vibrant and natural colors will be
perceived. Below are CRI rating comparisons for some common lamps:
LU400 High Pressure Sodium 22 CRI
MH400/U Metal Halide 65 CRI
F34CW/SS standard cool white lamp 62 CRI
F32T8/841 quality 4100K T8 lamp 82 CRI
EFFICACY: Term used to express the efficiency of a light source
in lumens per watt (LPW).
FLUORESCENT: A type of lamp that uses an electric arc passing
between two cathodes to excite mercury (and other) vapors to
produce UV radiant energy. The phosphor coating on the inside
of the lamp converts this energy to visible light.
FOOT CANDLE (fc): A unit of illuminance equal to 1 lumen per
square foot.
HALOGEN: This is the type of gas that fills Quartz Halogen, sometimes
called Tungsten Halogen lamps. "Tungsten" refers to the material that
the filament is made of.
HIGH INTENSITY DISCHARGE (HID): Lamps that use a pressurized arc
tube to generate the light source. Typical HID lamps are High Pressure
Sodium (HPS), Metal Halide and Mercury Vapor.
HIGH OUTPUT (HO): 800ma Rapid Start lamp with recessed double
contact bases.
INCANDESCENT: A lamp that produces light by passing current through
a filament inside a vacuum or gas filled bulb.
INITIAL LUMENS: Lumen output of a lamp after 100 hours of operation.
KELVIN TEMERATURE (K): Designation used to describe the color of a
lamp, typically between 2700K and 7500K. The lower the number
(2700K) the more yellow/orange the lamp color would be. Warm White
lamps are 2700K. The higher the number (6500K) the more blue the
lamp would be. Daylight lamps are 6500 to 7500K. The most common
color is 4100K which is Cool White.
LAMP: A manufactured light source, consisting of four main types:
incandescent, fluorescent, HID and LED.
LAMPHOLDER: A "socket" used to hold the end of a lamp in position.
LED: Light Emitting Diode, solid state electronic light source.
LUMEN: Unit used to measure the light output of a given source.
MEAN LUMENS: Lumen output after 40% of rated life.
MEDIUM BASE: A 1" diameter screw-in lamp base, sometimes called
"Edison Base".
MOGUL BASE: A 1-1/2" diameter screw-in lamp base.
PULSE START: An HID ballast that uses an ignitor to cause a
"Pulse" of current to the lamp, resulting in faster start up time
and higher maintained lumens.
SLIMLINE: 430ma single-Pin based fluorescent lamps.
T8, T12, BR30, BR40, etc: Designation used to describe the diameter
of a lamp in 1/8" increments. A T8 lamp for instance would be 1"
diameter.
VERY HIGH OUTPUT (VHO): 1500ma Rapid Start fluorescent lamp
with recessed double contact bases.
WATT: Unit of electrical power used to describe the amount of energy
consumed by a lamp. The wattage of a lamp does not indicate how bright
it is. The proper way to compare the brightness of different lamp types
is by their lumen output.