3M LED Advanced Light
T8 LED Tube Lamps
Glossary and FAQs
Active Power
Ambient Temperature
Amperes (Amps)
ANSI
ANSI Ballast Type
Average Rated Life
The system input power (in watts) for a lamp ballast combination.
The temperature inside the fixture in the air surrounding the fluorescent lamp or LED.
Fluorescent lamp light output and LED life are affected by the ambient temperature.
A measure of electrical current. In incandescent lamps, the current is related to voltage and
power as follows: Watts (power) = Volts x Amps (current).
A 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 reference to the ANSI document describing the lamp which also lists the characteristics of the
ballast required to operate the lamp. Technically, therefore, it is incorrect to refer to "Ballast
Type" with the ANSI code but this misuse is common. The following naming system is used: H –
mercury lamps; M – metal halide lamps; S – high pressure sodium lamps; L – low pressure sodium
lamps.
The number of hours at which half of a large group of product samples fail under standard test
conditions. Rated life is a mean value, any lamp or group of lamps may vary from the published
rated life.
A circuit that senses lamp end life and will automatically shut off power to the lamp(s). When a
Auto reset shutdown
new lamp is inserted in the socket, the ballast resets and turns on the lamp automatically. Some
circuit
shutdown circuits require the power to be cycled before a new lamp will relight.
A device which provides the necessary starting voltage and appropriate current to a fluorescent
Ballast
or high intensity discharge (HID) luminaire.
An LED replacement lamp for a fluorescent T8 that requires the removale of the current
fluorescent ballast and rewiring of the incoming line voltage directly to the fixture. Usually the
best option for someone who is looking to complete relamping where the ballasts are replaced at
Ballast Bypass T8 tube
the same time. Involves upfront labor costs but in the long term, this options typically provides
the best ROI.
light
Ballast Case Temperature The measured operating temperature of a fixture’s ballast. Operating outside of a ballast’s
(BCT)
specified operating temperature will shorten its functional lifespan.
This is the percentage of a lamp’s rated lumen output that can be expected when operated on a
specific, commercially available ballast. Note that the “rated output” is sometimes measured on
a reference ballast unlike ones that actually operate the lamp in the field. For example, a ballast
with a ballast factor of 0.93 will result in the lamp's emitting 93 percent of its rated lumen
output. A ballast with a lower BF results in less light output and also generally consumes less
Ballast Factor
power.
Ballast Losses
Power or energy dissipated in the ballast as heat and not converted to lamp energy.
Ballast Luminous Efficiency A new (2011) metric measuring the ratio of total fluorescent lamp arc power to the input power
(BEL)
supplied to the ballast.
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Color Quality Scale
The number of hours at which half of a large group of ballasts fail under standard test conditions.
Rated life is a median value, any ballast or group of ballasts may vary from the published rated
life.
The angle at which luminous intensity is 50 percent of the maximum intensity
The separation of LEDs according to color temperature subsequent to a production run for full
manufactured, distribution in terms of color, lumen output and forward voltage. This allows
luminaire manufacturers to select only those LEDs that meet their acceptable performance
ranges and also maintain consistency in production.
Any base with two metal pins for electrical contact. This is the typical base for a fluorescent tube
of one to four feet in length. It consists of two prong contacts that connect into the fixture.
Medium bi-pins are used with type T-8 and T-12 tubular fluorescent lamps and miniature bi-pins
are used for tubular T-5 fluorescent lamps.
An eletromagnetic ballast that disconnects the electrode-heating circuit after the lamps are
started. Cathode disconnect ballasts operate lamps at 60 hz; they are sometimes called "hybrid"
or 'low frequency electronic" ballasts. They operate lamps at lower power than other magnetuc
ballasta that produce similar light output.
A new color metric proposed by NIST (US National Institute of Standards) based on fifteen color
chips instead of the eight used in CRI.
Color Rendering Index
Compact Fluorescent
Lamps (CFL)
Cool white
A rating index commonly used to represent how well a light source rendera the colors of objects
that it illuminates. For a CRI value of 100, the maximum value, the colors of objects can be
expected to be seen as they would appear under an incandescent or daylight spectrum of the
same correlated color temperature (CCT). Sources with CRI values less than 70 are generally
regarded as rendering colors poorly, that is colors may appear unnatural. Sunshine is a CRI of 100.
A family of single-ended fluorescent discharge light sources with small diameter (16mm or less)
tubes.
A term loosely used to denote a color temperature of around 4000 degrees Kelvin.
Ballast Rated Life
Beam Angle
Binning
Bi-Pin
Cathode Disconnect
Ballast
Curent THD
The color appearance of emitted light, measured by a general "warmth" or "coolness" of visual
appearance; measured in units of kelvin (K), a low color temperature (below 3200 K) implies a
warmer (more red/yellow) light, color temperatures from 3200 to 4000 K are neutral and a high
color temperature (above 4000 K) implies a cooler (more blue) light, sunlight's CCT is 5780 K.
A measure of the degree to which the current waveform deviates from sinusoidal, expressed as a
percentage. See also total harmonic distortion (THD).
Daylight sensor
A device which senses the amount of daylight in a room and controls the luminaire accordingly.
Correlated Color
Temperature (CCT)
Dimming Ballast
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.
A device that provides the the abiliyt to adjust light levels by reducing the lamp current. Most
dimming ballasts are electronic.
Direct Replacement LED
T8
As the name implies, this lamp is a direct replacement for the current fluorescsnt T8 and ballast
system. To replace the fluorescent T8 with the LED T8, all one does is twist out the old T8 and
twist in the new T8. This is the most cost effective solution for upfront costs and are the majority
of the tubes in the marketplace today. Consideration must be given to the ballast that is in the
system as not all ballasts are compatible with the LED direct replacement T8s.
Driver
Ears
For light emitting diodes, a device that regulates the voltage and current powering the source.
See tombstones.
Dimmer
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Efficacy
A measure expressed in lumens per watt representing the efficiency of a lamp/ballast sytem or
luminaire.
Efficiency
Electrodes
The efficiency of a light source is simply the fraction of electrical energy converted to light, i.e.
watts of visible light produced for each watt of electrical power with no concern about the
wavelength where the energy is being radiated. For example, a 100-watt incandescent lamp
converts seven percent of the electrical energy into light; discharge lamps convert 25 percent to
40 percent into light. The efficiency of a luminaire or fixture is the percentage of the lamp lumens
that actually comes out of the fixture.
The structure that serves as the electric terminals at each end of the discharge lamps.
High-frequency electronic ballasts and other electronic devices can produce a small amount of
Electromagnetic
radio waves that can interfere with radio and TV. Federally-mandated requirements must be met
Interference (EMI)
for EMI levels before an electronic device is considered FCC compliant.
Use solidstate electronic components and typically operate fluorescent lamps at frequencies
greater than 25 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
Electronic Ballast
HID (high intensity discharge) lamps.
Comprehensive energy legislation passed by the U. S. Congress. The lighting portion includes
lamp labeling and minimum energy efficacy (lumens/watt) requirements for many commonly
used incandescent and fluorescent lamp types. Federal
Canadian legislation sets similar minimum energy efficacy requirements for incandescent
reflector lamps and common linear fluorescent lamps. Provides for tax deductions for
Energy Policy Act (EPACT) replacement of inefficient bulbs.
Energy Service Company A company dedicated to helping commercial and industrial clients reduce their energy
(ESCO)
consumption.
Field of view
The area covered by an occupancy sensor, oftgen reported as a horizontal field of view.
Fixture
A complete lighting unit consisting of lamp or lamps and the parts designed to distribute the light.
A 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.
A unit of measure for the density of light as it reaches a surface. One foot candle is equal to one
lumen per square foot.
The number of cycles completed by a periodic wave in a given unit of time. Frequency is reported
in in cycles per second, or Hertz (Hz).
A term to describe light sources that are similar to some forms of natural daylight 5000K and 90+
CRI.
An electric lamp that produces light from gas atoms excited by an electric current.
A practice of replacing all the lamps at an installation all at the same time whether or not they
have burned out. Often when replacing fluorescents tubes, the ballast is replaced at the same
time.
A component or integral part of luminaire that conduct or convect heat away from LED
components.
Fluorescent Lamp
Foot Candle (FC)
Frequency
Full spectrum lighting
Gas discharge lamps
Group relamping
Heat Sink
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High Bay
High Intensity Discharge
lamp (HID)
High Pressure Sodium
Lamp (HPS)
Hybrid LED T8
replacement
Ignitor
Initial lumens
Indirect lighting
Input Voltage
Input Watts
Instant Start Ballast
IT DEPENDS
Inverter
Kelvin Temperature
Kilowatt
Kilowatt hour
Lamp
Lamp efficacy
LED Driver
Lighting used in industrial applications where the ceiling height is greater than 20 feet. Common
in big box retail, industrial, warehouse and manufacturing spaces.
A 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.
HPS lamps are high intensity discharge light sources that produce light by an electrical discharge
through sodium vapor operating at relatively high pressures and temperatures.
See Universal LED T8.
An electronic device providing a high voltage pulse to initiate an electrical discharge. Typically,
the ignitor is paired with or is a part of the ballast.
The lumens produced by a lamp after an initial burn in period (usually 100 hours).
Light arriving at a surface after reflecting from one or more surfaces (usually walls and or ceilings)
that are not a part of the luminaire.
Power supply voltage required for proper operation of fluorescent or HID ballast.
The total wattage required by both the ballast and the lamp in a luminaire.
A 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.
The answer to most lighting questions.
Also known as power inverter. A device used to convert direct current (DC) into alternating
current (AC)
A numerical scale used to describe the color of light. Light with a lower Kelvin rating will have a
more yellow tint, while light with a higher kelvin rating will have a more blue tint.
1000 Watts.
1000 Watts of power used continuously for one hour.
The source of light in a fixture, colloquially called a "light bulb."
The ratio of light output of a lamp (lumens) to its active power (Watts), expressed as lumens per
watt (LPW).
An electronic devise which converts input power into a constant current source despite
fluctuation in voltage. It protects LED from voltage fluctuations. In simple terms an electronic
devise which feed input power to LED to produce light.
Lamp Lumen Depreciation Factor. The multiplier to be used in illumination calculations to relate
Lamp lumen depreciation the initial rated output of light sources to the anticipated minimum rated output based on the
factor (LLD)
relamping program to be used. See also Lumen Depreciation and Mean Lumens.
Lighting used in industrial applications where the ceiling height is 20 feet or less. Common in big
Lo-Bay lights
box retail and industrial settings.
The approved method by IES for making photometric measurement of LED light products. LM-79
measures total luminous flux, luminous intensity distribution, electrical power, efficacy and color
characteristics (chromaticity, CCT, and CRI).
LM-79
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LM-80
LPW
Lumen depreciation
Lumen Maintenance
Lumens
Luminaire
Luminaire Efficiency
LUX
Magnetic Ballast
Maximum Ambient
Temperature
Medium Bi-Pin
Metal Halide Lamp
Miniature Bi-Pin
Minimum ambient
temperature
National Energy Standard
for Fluorescent Ballasts
National Electric Code
(NEC)
National Stock Number
(NSN)
A measurement standard developed by IES which allows user to evaluate and compare the lumen
maintenance of LED components from different manufacturer at standard operating condition.
LED packages, arrays or LED modules can be tested at three junction temperatures typically at
55°C, 85°C and manufacturer specified temperature for 6000 hours. The approved method of
measuring lumen maintenance is only for LED light source not complete luminaire.
Lumens per Watt.
The decrease in lumen output of a light source over time; every lamp type has a unique lumen
depreciation curve (sometimes called a lumen maintenance curve) depicting the pattern of
decreasing light output.
Lumen maintenance is the standard lighting term for the percentage of initial lumens that a light
source maintains over time. For instance, P-2s QHC maintains 70 percent of initial lumens over
60,000 hours and specified as L70 over 60,000 hours (or 30 percent of deterioration in the
amount of light produce by QHC over a period of 60,000 hours). Lumen maintenance is often
specified as L50, L70, L80, or L90. In each case, L stands for lumen maintenance and the number
is the percentage of light output remaining.
A unit of luminous flux; overall light output; quantity of light, expressed in lumens.
A complete lighting unit which contains a lamp, housing, ballast, sockets and any other necessary
components.
The ratio of lumens emitted by a luminaire to the total lumens emitted from the light source
within the luminaire.
A unit of illuminance equal to one lumen per square meter.
A ballast used with discharge lamps that consists primarily of transformer-like copper or
aluminum windings on a steel or iron core. Also called “Core and Coil” (see Electronic Ballasts).
The maximum ambient temperature of the ballast case for which the manufacturers life rating is
valid.
A type of connector commonly used on T8 and T12 fluorescent lamps. Two small pins protrude
from the lamp ends, which are inserted into a socket in the fixture.
A high-intensity discharge light source operating at a relatively high pressure (about one
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
rendering.
A type of connector commonly used in T5 lamps. Similar in design to but smaller than medim bipin connectors. Two small pins protrude from the lamp ends, which are inserted into a socket in
the fixture.
The minimum temperature at which a fluorescent lamp is warranted to start.
A federal law enacted in 1988 that sets energy standards for ballasts consistent throughout the
United States.
A nationally accepted electrical installation code to reduce the risk of fire, developed by the
National Fire Protection Association.
The standardized part number used by the U.S. Government for procurement.
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Non shunted tombstones
(lampholders)
Occupancy Sensor
Operating Cycle
Operating Electrode
Voltage
Has four holes (or accept a total of four wires) on the unit ad are used typically by rapid start
ballasts.
A device which activates a fixture upon sensing the presence of a person.
The frequency with which lamps are cycled on and off.
Phosphor
The voltage the ballast supplies to a lamps electrodes.
Refers to ballasts that employ multiple output current paths from a single ballast to allow lamps
to operate independent of one another, allowing other lamps operated by the ballast to remain
lit should companion lamp(s) fail.
An 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 visible
light.
Power Factor
A measure of the effectiveness with which an electrical device converts volt-amperes to watts;
devices with power factors (< 0.90) are “high power factor” devices.
Parallel Lamp Operation/
Parallel Wiring
Preheat
Preheat time
Programmed Rapid Start
Programmed start
Rapid Start
Rated lamp life
Restrike time
Self ballasted lamps
Series Lamp Operation
Shunted tombstones
(lampholders)
Solid State lighting
Specular reflection
A method of starting fluorescent lamps in which the electrodes are heated before a switch opens
to allow a starting voltage to be applied across the lamp. With preheat starting, the lamp flashes
on and off for a few seconds before staying lit because several startgin attempts may be
necessary to establish the electric arc across the lamp electrodes.
For rapid start lamps, the time from the onset of lamp current to the lamp arc's striking during
which the lamp electrodes are heated to ease starting.
Lamp starting method which preheats the lamp filaments while not allowing the lamp to ignite
and then applies the open circuit voltage (OCV) to start the lamp.
Refers to a type of rapid start ballast that optimizes the startgin process by waiting until the
lamps electrodes have been heated to apply the startgin voltage, thus easing the load to the
electrodes and extending lamp life.
A method of starting fluorescent lamps in which the elctrodes are heated prior to starting, using a
starter that is an integral part of the ballast. Heating the electrodes before starting the lamps
reduces the voltage required to strike the electric arc between the electrodes. A rapid start
system starts smoothly without flashing.
Lamps are tested in a controlled environment and the point at which 50 percent of a given
sample size burns out is listed as the lamps average lamp life.
The time required for a lamp to restrike, or start, and to retrurn to 90% of its stabilized light
output after the lamp is extinguished.
A discharge lamp with an integral ballasting device allowing the lamp to be directly connected to
a socket providing line voltage (see CFL).
Refers to ballasts that employ a single current path passing through all lamps operated by the
ballast. If one lamp should fail, companion lamps operated by the same ballasts will also
extinguish or dim.
Will have two holes (or accept two wires) on the unit and are used with instant start ballasts.
A description of the devices that do not contain moving parts or parts that can break, rupture,
shatter, leak or contaminate the environment
Reflection from a smooth, shiny surface, as opposed to diffuse reflection
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Starter
An electronic module or device used to assist in starting a discharge lamp, typically by providing a
high voltage surge
Starting time
Starting voltage
The method a ballast uses to start a lamp. For compact fluorescent lamps, ballasts use one of
three methods: preheat, instant start, or rapid start. Dimming electronic ballasts use one of
three starting methods: rapid start, programmed start, or controlled rapid start.
The minimum temperature at which the lamp will start reliably on the ballast
The time it takes for a lamp to start from the point at which voltage is applied to the lamp until
stable operation.
The voltafge applied across the lamp during starting.
Supply Voltage
The voltage, usually direct, applied by an external source to the circuit of an electrode.
Starting method
Starting temperature
A 5/8-inch diameter fluorescent lamp. “T” stands for tubular, while the number “5” stands for the
T5
5 in 5/8-inch. Therefore a T8 lamp would be a Tubular 8/8-inch, or one-inch diameter lamp.
T8
A one-inch diameter fluorescent lamp.
T12
A one and one half-inch diameter fluorescent lamp.
Total Harmonic Distortion A measure of the distortion of an electrical wave form. Excessive THD (defined by ANSI as greater
(THD)
than 32 percent) may cause adverse effects to the electrical system.
The part of the fluorescent fixture that holds the T8 tubes in place. There are two/tube. Also
Tombstones
called ears.
A recessed luminaire shaped like an inverted trough used to enclose and reflect fluorescent
Troffer
lamps.
Transformer
Electrical devices which change distribution voltages to higher or lower levels.
A private organization which tests and lists electrical equipment for electrical and fire safety
Underwriters Laboratories according to recognized UL and other standards.
Universal T8
Voltage
Warm up time
Warm White
Watt
3M Company
3M Center, Building 220-07-E
St. Paul, MN 55144-1000 USA
1-800-430-5000
3MLighting.com/LED
The most recent adition to LED T8 replacements. This LED T8 can be used as either a direct
replacement T8, or as a ballast bypass T8. It is compatible with the ballasts currently employed by
fluorescent T8s and is compatible with voltages ranging from 90 to 320V. It can be used with or
withuot a ballast. This is the most "universal" of all options available.
A measurement of the elctromotive force in an electrical circui or device expressed in volts.
Voltafge can bbe thought of as being the sames as pressure in a waterline.
The time it takes for a lamp to produce 90 percent of its stabilized light output when it is started,
unless otherwise indicated.
Refers to CCT (color temperture) around 3000K, providing a reddish to yellowish white hue.
A unit of electrical power. Lamps are rated in watts to indicate the rate at which they consume
energy.
3M is a trademark of 3M. Used
under license in Canada. All other
trademarks herein are property of their
respective owners.
Updated 5.5.15
98-0004-1032-8
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