We try to keep our product descriptions as simple and straight forward as possible but from time to time those industry comments and words creep in, so we thought we would help you by adding this glossary of terms and any recurring questions we think you may have when choosing your lighting. We hope this helps but if you are unsure about ANYTHING Please, don’t hesitate to call us, we love talking to and helping our customers…
A
AC (~)
Alternating Current, as found in the mains power supply.
Accent Lighting
Also commonly called display or highlighting. Accent lighting is typically at a
higher intensity to emphasise an object or area. A Ratio of 3:1 versus ambient
lighting is recommended for accent lighting to be noticeable.
Ambient
Temperature (Ta)
The air temperature surrounding the luminaire or component. LED luminaires are
particularly temperature sensitive with excess temperature affecting
performance and rated life. See also Junction Temperature.
Amenity
Lighting
Decorative lighting intended to enhance the appearance of a building or an
outdoor area. Can include Mood lighting of hotels, bars, restaurants and other
leisure activities.
IT DOES NOT INCLUDE lighting to provide general illumination or circulation or
building lighting.
Ampere (Amp)
The unit for measuring rate of flow of electrical current:
Current (Amps) = Power (Watts) / Voltage (Volts)
Asymmetric
Light Distribution
Where the distribution of light from a luminaire is not even in one plane.
Common in display luminaires such as ‘wall washers’ where light is directed
intentionally in one direction.
Azimuth
The ‘swivel’ angle, as used in floodlighting or display lighting designs and
installations.
B
Ballast
In a fluorescent lighting system, regulates the current to the lamp and
provides sufficient voltage to start the lamp.
Ballast
Lumen Factor (BLF)
The proportion of light emitted by a luminaire when in emergency mode, usually
powered by batteries, compared to the normal mains powered output. BLF figures
can be less than 10% or 0.1 as emergency lighting levels are far lower than
those required for normal lighting.
Bathroom Zones
Bathroom lighting needs to be functional and safe. It is divided into zones
where only suitable light fittings should be used.
· ZONE 0 is inside the bath or shower. Any fitting used in this zone must be low voltage, max 12v) and rated at least IP67 which is immersion proof.
· ZONE 1 is the area above the bath to a height of 25m from floor. In this zone a minimum rating of IP65 is required.
· ZONE 2 is the area stretching 6m outside the perimeter of the bath and the area between zone 1 and the ceiling upto 3m. Also the area around the wash basin, within a 60cm radius of any tap. In this zone a minimum rating of IP44 is required.
Bayonet
Cap
A common lamp cap found on many lamps in domestic use in the UK. The lamp cap
has two small pins that protrude from the base, these are inserted into the
lamp holder and lock the lamp in place as it is rotated. B15 and B22 are the
most common types.
Beam
Angle
Not, as commonly thought, the width or angle of light emitted from the
lamp/luminaire. Instead, the point where intensity reaches 50% of the peak
value.
Binning
The method used for sorting LED chips during manufacture, typically based on
output and colour temperature. The latest manufacturing techniques employed by
leading chip manufacturers are yielding chips that no longer require binning as
the consistency and tolerance is greatly improved.
Brightness
Whilst brightness is what people see and react to, luminance is the actual
surface brightness of an object and is measured in candelas per metre2.
British Building Regulations
Various building regulations, usually referred to as the approved regulation
document letter, exist not only to ensure that buildings are constructed safely
but also that materials or equipment installed is of the current requirement.
Various products comply with:
· DOCUMENT B – Fire Safety
· DOCUMENT C – Resistance to contaminants and moisture
· DOCUMENT E – Resistance to sound
· DOCUMENT L – Conservation of fuel and power
British
Standards Institute (BSI)
The national standards organisation is responsible for publication of standards
that ensure products are constructed and operated safely and efficiently.
Standards are prefixed with BS for a British Standard, EN for a European
Standard and BS EN where the European Standard has been adopted as a British
Standard.
All BG Electrical products are conceived and produced to comply with the
relevant standards, key standards for the LED range include:
· EN 60598-1 – Luminaires – General requirements
· EN 55015 – Limits and methods of measurement of radio disturbance characteristics of electrical lighting and similar equipment
· EN 61547 – Equipment for general lighting purposes – EMC immunity requirements
· EN 61000-3-2 – Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for Harmonic current emissions
· EN 62471 – Photobiological safety of lamps and lamp systems
· EN 62560 – Self-ballasted LED-lamps for general lighting services by voltage 50 V. Safety specifications
· EN 61347-1 – Lamp control gear – Part 1: General and safety requirements
· 2002/96/EC – Waste Electrical & Electronic Equipment (WEEE)
· 2002/95/EC – Restriction of the use of certain Hazardous Substances in EEE (RoHS)
· (EC) No 1907/2006 – The Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)
C
Candela
The SI unit for luminous intensity.
CE
The European Community mark ‘Conformité Européenne’ signifying all relevant
standards and directives have been complied with.
CEN
The European body responsible for the preparation of other (Non- Electrical)
standards in Europe.
Cenelec
The European body responsible for the preparation of electrical standards in
Europe.
CFF
Critical Fusion Frequency – 60-100Hz
CFL
Compact Fluorescent Lamp.
Chip
The LED Chip is the light source.
Chip on
board
Is the latest generation of LED light source. Many small LED chips are
incorporated in one packaged light source to provide a more efficient solution
that can be combined with a lens and/or reflector to maximise the light
distribution.
Class I
Class one luminaires require an Earth connection for electrical safety.
Class II
Colour
Appearance
Term used to describe how “white” the emitted light looks. Commonly,
warm, neutral, cool and daylight are used to categorise.
Colour
Rendering Index (CRI)
A measure of the degree of colour shift objects undergo when illuminated by the
light source as compared with those same objects when illuminated by a
reference source of comparable colour temperature. The reference source has a
CRI of 100. Natural light (daylight) would also be 100.
Correlated
Colour Temperature (CCT)
The description used to describe the effect of heating an object until it glows
incandescently, the emitted radiation, and apparent colour, changes
proportional to the temperature; easily envisioned when considering hot metal
in a forge that glows red, then orange, and then white as the temperature
increases. Measured in degrees Kelvin.
3300K WARM WHITE 3300K – 5300K NEUTRAL WHITE 5300K COOL WHITE
Corridor
Function
Refers to luminaires that when not required to emit 100% light output, switch
to 10% output. This ‘standby mode’ allows the luminaire to provide a low level
of illumination for a feeling of security so the area is not totally dark. Upon
sensing movement the output automatically and instantly switches to 100%. This
is particularly useful in circulation areas such as corridors and stairwells.
Cut Off
Angle
Small downlights can appear too intense and very glary, so cut off angle
illustrates the point where the light source can’t be seen.
Cut-out
Dimension
Size of hole required to install luminaire.
D
DALI
Stands for Digital Addressable Lighting Interface, where each driver and
control component such as a sensor or switch has a unique address on the
lighting installation. This allows for infinite configuration of the lighting
installation and flexibility in the future.
Dimming
Many Luceco luminaires are available as a dimmable version option. Generally
this requires a different driver to the standard fixed output driver and also
may require additional wiring on site to control the dimming function.
Direct
Lighting
Luminous flux that reaches the working plane without being reflected from
walls/ceiling or within the luminaire itself.
Display
Lighting
Comprises lighting intended to highlight displays of exhibits, merchandise and
other associated uses. Spot projector for shops, theatres, galleries and
studios.
DLO
Light Output in a downward direction.
DLOR
Downward Light Output Ratio is the percentage of luminous flux output from the
lamp/luminaire that is emitted in the 180° angle below horizontal.
Double
Insulation
Also known as Class II, where two levels of insulation (such as two cable coverings)
protect live parts from exposure.
Driver
The driver is often the critical component in a LED luminaire or lamp, more so
than the LED chip itself. The driver has to be matched to the power
requirements of the LED chip and also have quality components. Drivers that use
inferior components such as capacitors, will fail before the rated life of the
LED chip, reducing the claimed life by as much as 50%.
E
Edge Lit
This means that the LED chips are positioned vertically around the perimeter of
the panel. This provides an excellent uniformly illuminated panel in a fixture
as slim as 8mm.
Edison
Screw
A lamp cap that features a screw thread for a positive fit in the lampholder,
common sizes include E15 and E27.
Efficacy
Is the measure of how efficient a lamp or luminaire is. This can be expressed
as (source) lumens per Watt, which is the normal measure for lamps. Or, as
luminaire lumens per circuit Watt, which is common for luminaires. The figure
for luminaires will also include the LOR of the luminaire in the calculation.
Efficient
White Light Units
Products that are specifically designed to provide efficient, high quality
illumination.
ELV
Extra Low Voltage.
Emergency
Lighting
Allows the safe evacuation of an area in the event of a mains failure. The
positioning and number of emergency lighting luminaires is detailed in British
Standard BS5266. It is vital that emergency lighting is maintained correctly to
ensure batteries are conditioned, so it operates when required.
Escape
Route
Emergency lighting along a route such as a corridor or staircase to enable safe
evacuation.
EPREL
European Product Registration Database for Energy Labelling.
Exterior
Area Lighting
Covers all exterior lighting which is intended to provide downward light onto
horizontal or near horizontal surfaces, including roadways, carparks, paths,
stairs, ramps, gardens and other open surfaces.
Exterior
Floodlighting
Lighting that is intended to light vertical or near vertical surfaces including
floodlighting of buildings, monuments and statues.
F
F Mark
Denotes luminaires that can be mounted on to flammable surfaces as the heat
generated will not cause any combustion. Previously luminaires that were suitable
had to be marked, but the most recent standard requires only luminaires that
don’t comply to be marked.
Fire
Rated
Where a luminaire is installed in a fire barrier such as into a ceiling, it
must have the same resistance to fire rating as that barrier. For domestic
installations there are ratings of 30, 60 and 90mins and each limit must be
tested for. A 90min rated product does not automatically comply with 30 or
60mins due to the different ceiling constructions. Non-domestic applications
usually have a fire-resistant barrier such as a concrete slab between floors
and so do not have the requirement in many cases.
Flux/Luminous
Flux
Luminous flux is the measure of the perceived power of light, adjusted to
reflect the varying sensitivity of the human eye to different wavelengths of
light and is expressed in Lumens (lm).
Frequency
(Hz)
Rate that the power supply wavelength fluctuates and is measured in Hertz.
G
General
Lighting
Lighting to illuminate the general area without supplementary task lighting.
Glare
Difficulty seeing in the presence of bright light such as direct or reflected
sunlight or artificial light. Proportional to the background illuminance; a
good example is a car headlight that creates glare at night time but not during
the day.
Goniophotometer
A photometric device for testing the luminous intensity distribution,
efficiency, and luminous flux of luminaires.
H
Heat Sink
A part of the thermal system that conducts or convects heat away from sensitive
components, such as LEDs and electronics.
HELU
High Efficiency Lighting Unit.
Hertz
(Hz)
The unit to measure frequency.
HID Lamp
High Intensity Discharge Lamp – type of electrical gas discharge lamp which
produces light by means of an electric arc between tungsten electrodes housed
inside a translucent or transparent fused quartz or fused alumina arc tube.
High
Power LED
A high power LED, sometimes referred to as a power LED, is one that is driven
at a current of 350mA or higher.
High Risk
Area
A requirement in emergency lighting where a process may require safe shut down
or an increased hazard. Higher emergency lighting levels are therefore required
local to the risk.
I
IEC
International Electrotechnical Commission.
IES
Illuminating Engineering Society, an American organisation that provides
standards and recommendations. Photometric data files are commonly in .ies file
format.
Illuminance
The intensity of light falling on a surface area. If the area is measured in
square feet, the unit of illuminance is footcandles (fc). If measured in square
meters, the unit of illuminance is lux (lx).
Indirect
Lighting
Lighting that is reflected by room surfaces or within the luminaire before
falling on to the working area. As a result of reflection it is often lower in
intensity and glare.
Ingress
Protection (IP) Rating
A system that identifies the protection that a lamp or luminaire has against
solid objects and water. The first digit being solid object protection and the
second one resistance to water.
| Protection against solid foreign objects | Protection against harmful ingress of water | ||
| IP | Tests | IP | Tests |
| 0 | No Protection | 0 | No Protection |
| 1 | Full penetration of 50mm diameter of sphere not allowed. Contact with hazardous parts not permitted. | 1 | Protected against vertically falling drops of water. |
| 2 | Full penetration of 12.5mm diameter of sphere not allowed. The jointed test finger shall have adequate clearance from hazardous parts. | 2 | Protected against vertically falling drops of water with enclosure tilted 15° from the vertical. |
| 3 | The access probe of 2.5mm diameter shall not penetrate. | 3 | Protected against sprays to 60°from the vertical. |
| 4 | The access probe of 1mm diameter shall not penetrate. | 4 | Protected against water splashed from all directions – limited ingress permitted. |
| 5 | Limited ingress of dust permitted (no harmful deposit). | 5 | Protected against low pressure jets of water from all directions – limited ingress permitted. |
| 6 | No ingress of dust. | 6 | Protected against strong jets of water e.g. for use on ship decks – limited ingress permitted. |
| 7 | Protected against the effects of immersion between 150mm and 1m. | ||
| 8 | Protected against continuous submersion at a specified depth. |
Initial
Lumens
The output up to 100 hours use.
Inrush
Current
Components such as drivers can have high inrush currents for milliseconds due
to the use of capacitors; this should be considered when specifying switching
and breaker ratings.
Integrating
Sphere
A device used for a variety of optical, photometric, or radiometric
measurements.
IoT
Internet of Things – a system of physical things embedded with sensors,
software, electronics and connectivity to allow it to perform better by
exchanging information with other connected devices.
e.g. NEST smart home device, smart fridge, DHL tracking and monitoring.
Isolux
Diagram
A graphical representation of common illuminance levels to show lighting levels
over a calculated area.
J
Junction
The point at which the positive and negative conductors meet in a LED.
Junction
Temperature
A critical consideration in LED lamp or luminaire design. For every 10°C that
the junction temperature exceeds the optimum figure, life of the LED chip is
reduced by 50%. Overrunning LEDs by operating at higher amps will cause this to
happen.
K
Kelvin
The SI unit used to measure and denote colour temperature, degrees Kelvin.
kWh
Kilo-Watt-hour is the typical billing unit for electricity costs and represents
1kW of power over a 1 hour duration.
L
Lamp
A lamp converts electrical power into light and sometimes they are called
“bulbs” due to the traditional lamp shape.
LED
Light Emitting Diode. An LED is a solid-state semiconductor device that
converts electrical energy directly into light. On its most basic level, the
semiconductor is comprised of two regions. The p-region contains positive
electrical charges while the n-region contains negative electrical charges.
When voltage is applied and current begins to flow, the electrons move across
the n-region into the p-region. The process of an electron moving through the
p-n junction releases energy. The dispersion of this energy produces photons
with visible wavelengths. Most LEDs emit a blue light as that is the most
efficient format, a phosphor coating turns the blue light into the white light
required.
LED Rated
Life
LED chip figures are quoted by the chip manufacturer and in some cases these
are not translated when the chip is used in a luminaire, where it can run
hotter. As heat affects the LED chip, the life can be reduced dramatically.
Light
Output Ratio (LOR)
Percentage difference between the luminous flux emitted by the light source and
the amount emitted from the fixture it is housed in.
Llm/W
Luminaire lumens per circuit Watt is total lumens emitted from the luminaire
(source lumens x LOR) / total luminaire wattage including control gear.
LOR
Light Output Ratio – ratio of the total light emitted by the unit to that
emitted by the bare lamp(s).
Lumen
Depreciation
Describes the percentage of light lost relative to the initial lumen output.
LEDs depreciate at a far slower rate than other light sources, so a LED with a
lower initial output can quickly provide more light than a faster depreciating
light source.
Lumen
Maintenance
The luminous flux at a given time in the life of the LED. This is expressed as
a percentage of the intial luminous flux. This usually determines the rated
life of a LED product as the point it should be replaced.
Lumens
(lm)
The international (SI) unit of luminous flux. Lumens will become the measure of
light output as Watts cannot be a reliable measure due to the different
efficacy of light sources and the ongoing improvement in LED efficacy through
development.
Luminaire
A lighting fixture complete with installed lamps or light source.
Luminaire
Lumens (Llm)
The light emitted from a luminaire will typically differ from the source
lumens. This can be from losses within the luminaire housing. Also it is common
for LEDs to operate at a higher temperature in the luminaire; this can lead to
the output increasing when compared to the source (chip) lumens. Luminaire
lumens = source lumens x LOR
Luminaire
Wattage
Total wattage of LED and any control gear included.
Luminance
The surface brightness of an object measured in candelas/m².
Luminous
Efficiency
The percentage of total lamp lumens that a lighting fixture, luminaire, or
system emits, minus any blocked or wasted light.
Lux (lx)
The SI (International) unit of illuminance, or luminous flux incident on a unit
area, frequently defined as one lumen per square metre (lm/m²).
M
Maintained
Emergency
A Maintained emergency luminaire is able to be used for both general and
emergency lighting, a second live cable allows it to be turned on/off as
required and detect a mains power circuit failure.
Metal
Halide (MH)
Lamps that produce light by an electric arc through gaseous mixtures of
vaporized mercury and metal halides (compounds of metal with bromide and
iodine).
Microwave
Sensor
The sensor emits low power microwaves that form a pattern in the area covered.
When movement disturbs the pattern, movement is detected and the sensor turns
the light source on. Microwave sensors are only recommended for indoor use as
they are sensitive to movement and not heat.
N
Non-Maintained
Emergency
A Non-Maintained emergency luminaire ONLY operates in emergency mode and is not
for general lighting.
O
Open Area
Lighting also called ‘anti-panic’ area lighting is emergency lighting where not
a high risk area or escape route.
Organic
Light-Emitting Diodes (OLED)
Organic light-emitting diodes (OLEDs) are based on organic (carbon based)
materials. In contrast to LEDs, which are small point sources, OLEDs are made
in sheets which provide a diffuse area light source. OLED technology is
developing rapidly and is increasingly used in display applications such as
mobile phones and PDA screens. However, OLEDs are still some years away from
becoming a practical general illumination source.
P
PELV
Protected Extra Low Voltage.
Phosphor
A coating of phosphorescent material which photons from a royal blue LED pass
through, causing those photons to exit with a different colour property.
Photometric
Data
A generic term for light output and distribution data for a lamp or luminaire
and can be shown in many formats. Generally data is produced following the IES
or ELUMDAT method to provide a .ies or .ldt computer file for use in a lighting
design program such as Relux or Dialux. Photometric data is available for a
wide selection of BG Electrical luminaires from our downloads page.
PIR
Passive Infra Red sensors detect movement by the change in background
temperature as body heat moves into the area.
Power
Factor
The active power divided by the apparent power (i.e., product of the rms input
voltage and rms input current of a driver).
Power
Factor Correction
In an electronic device, such as a LED lighting fixture, a system of inductors,
capacitors, or voltage converters to adjust the power factor of electronic
devices toward the ideal power factor of 1.0.
Q
Questions – We are Here To Help
R
REACH
Registration, Evaluation, Authorisation and restriction of CHemicals. The EU
Directive covering the use of hazardous chemicals used in the maufacturing
process and supply of products.
Remote
LED Driver
Some LED lights in our range use a remote plug and play LED driver, that offers
flexibility to select either a fixed output, dimmable driver or emergency
versions, with all being interchangeable.
Remote
Phosphor
A phosphor conversion technique in which photons from a royal blue LED pass
through a phosphor material that is not attached to the LED chip.
RoHS
Restriction of Hazardous Substances (2002/95/EC) is an article 95 directive,
meaning it is across all European Union member states. Since July 1st 2006 the
use of hazardous substances is restricted in products, to prevent environmental
harm. The prohibited substances are Lead, Mercury, Cadmium, Hexavalent
Chromium, Polybrominated Biphenyls and Polybrominated Diphenyl Ethers. All
relevant Luceco products comply.
S
Self-Contained
The most common type of Emergency lighting luminaire, where all of the
components are within one Emergency luminaire. This can include gear boxes
connected directly to individual luminaires but outside the main luminaire
housing. If within 1m, it is classed as self-contained.
SELV
Safety Extra Low Voltage – less than or equal to 60VDC.
SMDs
Surface-mount LEDs.
Source
Lumens (lm)
Source or Chip lumens is the output of the LED array and does not allow for any
reduction or increase from the luminaire.
Source
Wattage
Could also be referred to as chip wattage – for the LED only and does not
include any control gear.
T
Task
Lighting
Localised lighting intended for a specific task.
Thermal
Management
Controlling the operating temperature of the product through design, examples
include heat sinks and improved airflow.
TLA
Temporal Light Artefact – Flickering light repeatedly brightened and dim.
Two types
Visible Flicker (low frequency)
Invisible (stroboscopic effect)
TLA
Measurement
Flicker Index (FI)
Percent Flicker (MD) modulation depth
Tp(a)
Fire Retardant Thermoplastic. Diffusers used on emergency lighting luminaires
and also certain applications where the percentage of diffusers against the ceiling
surface area is calculated must be of Tp(a) material.
Tp(b)
Diffusers are acceptable for the majority of applications, following the 2013
revision of the building regulations. Approved Document B – Fire Safety:
Volume: Building other than dwellinghouses, includes further detail.
U
ULO
Light Output in an upward direction.
ULOR
Upward Light Output Ratio, the percentage of light emitted from a lamp or
luminaire above the horizontal plane.
Ultraviolet
(UV)
Electromagnetic radiation with wavelength shorter than that of visible light.
LEDs emit minimal UV and therefore do not attract insects or potentially damage
sensitive materials illuminated by them.
Utilisation
Factor
In lighting design, the proportion of the luminous flux emitted by a light
source, which reaches the working plane.
V
Voltage
The term used to describe the electrical potential difference between
oppositely charged conductors.
W
Wattage
The power consumed by the LED.
X
Y
Z
