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LED

LED - means Light Emitting Diode. It is a semiconductor that glows when power is applied.
There are many different types of LED that are derived from the original concept.
SMD – surface mounted diode. This is a type of led that is mounted direct to PCB (printed circuit board) many SMDs can be mounted onto PCB to increase
COB – circuit on board These are LED that essentially have their own PCB. They can comprise of many semiconductors in one COB to increase light output.
CREE – people often think this is a type of LED but it is fact a brand of lensed SMD

Luminaire

Quite simply this the whole light fitting.

Wattage

Is quite simply the amount of power required to operate an electrical appliance or device measured in watts.

Colour temperature / Kelvin / CCT / RA / CRI

Colour temperature is the colour of the light emitted from the luminaire. Also known as CCT (correlated color temperature). Colour temperature is conventionally expressed in Kelvin, using the symbol K, a unit of measure for temperature based on the Kelvin scale. Color temperatures over 5,000K are called cool colours (white ranging to bluish white), while lower color temperatures (2,700–3,000 K) are called warm colours (yellowish white through red). Below is a Kelvin colour temperature scale

Color Rendering Index (CRI) is a measure the ability of a light source to accurately render all frequencies of its color spectrum when compared to a perfect reference light of a similar type (colour temperature). It is rated on a scale from 1-100. The lower the CRI rating, the less accurately colours will be reproduced. Light sources that are incandescent radiators have a CRI of 100 since all colors in their spectrum are rendered equally. Light sources that are not incandescent radiators will have Correlated Color Temperatures.

Examples of light sources with Correlated Color Temperatures, having CRI levels that are less than 100 would include LEDs. With lower CRI ratings these sources may also have too much green or magenta in their spectrums. An acceptable Color Rendering Index level for professional imaging is considered to be 90 or above.The value often quoted as 'CRI' on commercially available lighting products is properly called the CIE Ra value or RA, 'CRI' being a general term and CIE Ra being the international standard color rendering index.

Lumens and Luminous flux

Luminous flux is a measure of the amount of visible light emitted from a luminaire (light fitting). It is measured using the unit “Lumens” (Lm)
Below is a graph to give an idea of the light output of standard bulbs.

Minimum light output (lumens)Electrical power consumption (watts)
Incandescent (non-halogen)Compact fluorescent
200 25 3-5
450 40 9-11
800 60 13-15
1100 75 18-20
1600 100 24-28
2400 150 30-52
3100 200 49-75
4000 300 75-100

LED products are often measured in Lumens and Lumens per watt. As an example our 40w 600x600mm panel light emits 4003 lumens. That equates to just over 100 lumens per watt. As seen in the table above to get the same Luminous flux using incandescent, a 300w unit would have to be used. That would equate to 13 lumens per watt. Meaning the LED luminaire is near to 10 times more efficient.

Power factor

Power factor is basically the amount of power consumed that is turned into the intended output. In lighting terms, that is the amount of electricity turned into light. With lighting there is a by product of heat which is undesired energy. If you were to touch a conventional bulb whilst it was on would would burn yourself due to the amount of heat given off. LEDs give off much less heat. Power factor is measured from -1 to 1. -1 being that none of the input power is turned into the required output and 1 being that all the input power is converted into the desired output. Our LED products run between 0.9 and 0.95 which mean that are very efficient.

LM80 / Lumen maintenance / Lifespan

IES LM-80 is the Department of Energy (DOE) approved testing method for measuring lumen depreciation of solid-state (LED) light sources, arrays and modules. The Illumination Engineering Society (IES) and the Department of Energy Solid State Lighting Standards Development group worked together to create the LM-80 test criteria.
In LED lighting, lumen maintenance is the luminous flux remaining (expressed as a percentage of the initial output) at any selected elapsed operating time. Lumen depreciation is the luminous flux lost over time, and thus the complement of lumen maintenance.
Lumen maintenance compares the amount of light produced from a light source or from a luminaire when it is brand new to the amount of light output at a specific time in the future. For instance, if a luminaire produced 1,000 lumens of light when it was brand new and now produces 700 lumens of light after 50,000 hours, then it would have lumen maintenance of 70% at 50,000 hours. Useful lifetime estimates for LED lighting products are typically given in terms of the expected operating hours until light output has diminished to 70% of initial levels (denoted L70 life.)
There are a number of methods for controlling lumen maintenance areas:

  • Installing photoreceptors tied directly to ballasts, controlling the voltage output to the lamps based on the set level of luminance.
  • Connecting dimming ballasts directly to an energy management system that has been programmed for the expected depreciation of the lamps; the energy management system directs the output of ballasts as necessary to maintain required lighting levels over time.

Manually verifying lighting levels in a space by using photometers in specific locations, and then manually setting the system to meet lighting requirements.

When we state an LED luminaires lifespan we mean the amount of time it gives a useful amount of light until it drops to 70% of its original output.

Switching cycles 

This is the amount of times the luminaire can be switched on and off.

WEEE

The Waste Electrical and Electronic Equipment Directive (WEEE Directive) is the European Community directive 2012/19/EU on waste electrical and electronic equipment (WEEE) which, together with the RoHS Directive 2002/95/EC, became European Law in February 2003.

RoHS

The Restriction of the Use of Certain Hazardous Substances (RoHS) in Electrical and Electronic Equipment (EEE) Directive (2011/65/EU) was transposed into UK law on 2 January 2013.

This legislation bans the placing on the EU market of new EEE containing more than the agreed levels of:

  • lead (Pb)
  • cadmium (Cd)
  • mercury (Hg)
  • hexavalent chromium (Cr6+)
  • polybrominated biphenyls (PBB)
  • polybrominated diphenyl ethers (PBDE)

The National Measurement and Regulation Office (NMRO) is responsible for enforcing the RoHS legislation in the UK.

Manufacturers, authorised representatives, importers and distributors need to understand the obligations placed on them to ensure compliance.

CE

CE marking is a mandatory conformity marking for certain products sold within the European Economic Area (EEA) since 1985. The CE marking is also found on products sold outside the EEA that are manufactured in, or designed to be sold in, the EEA.