Glossary – Explanation of Technical lighting words etc

304 Stainless – A Grade of Stainless Steel, see A2 below.

306 Stainless – A Grade of Stainless Steel, see A4 below.

A2 – A Grade of Stainless Steel, also called 304.  Higher quality and corrosion resistance than standard type (300) Stainless Steels.

A4 – A Grade of Stainless Steel, also called 316.  Higher quality and corrosion resistance than 304/A2 Grade. Sometimes referred to as Marine Grade.

BREEAMBRE Environmental Assessment Method – See LEED Below.

CRI Colour Rendering Index measures the ability to distinguish different colours. Measured in Ra from 0 – 100. The higher the Ra, the easier it is to see the difference.

COBChip On Board – A type of LED module that appears as a single yellow phosphor circle on a white board.  Because of this, they are sometimes nicknamed “fried eggs”.

Driver An electrical Device which regulates the power to an LED.

Emergency ‘Maintained’the same LED is used for normal light output and for Emergency light output. When in emergency mode, the light output will be significantly lower – eg 8% of normal levels.

Emergency ‘Non-Maintained’a separate dedicated LED is used for Emergency mode.

EncapsulatedSinking the Driver (or other Electrical Part) in a Sand & Resin compound to dissipate heat, extend component life and minimise noise emissions. A disadvantage is that the Driver cannot be removed from its Enclosure once it has been encapsulated.

EPAEffective Projected Area – of a Luminaire is used to calculate suitable Pole strengths in various wind conditions.

IESIlluminating Engineering Society of North America.

IP RatingIngress Protection rating. A measurement of how well sealed a Luminaire is. The first digit after IP refers to dust protection, the second digit refers to water protection. Full details given separately – see Menu for Tech Info.

KDegrees Kelvin. See Colour Temperature.

L70 / L80 / L90 etc: Measurement of Life of LEDs or LED Modules in a Luminaire.  Given in hours, it indicates how many hours expected operation before the light output drops to 70%/80%/90% etc of initial light levels.  See LED Basics.

LEDLight Emitting Diode – is a semi-conductor light source.


LEED stands for Leadership in Energy and Environmental Design, and is run by the USGBC. It is commonly specified by US multinationals and like BREEAM, has a broad international appeal. There are a number of LEED certified buildings in Ireland. There is a great deal of similarity between the two assessment methods and they broadly cover most of the same criteria. However, LEED has a tendency to refer to US standards whereas BREEAM refers to European standards and can be tailored to use the building standards and best practice guides of the host country to demonstrate compliance.

For example, in the energy section of BREEAM, you demonstrate compliance by producing a BER or NEAP calculation for the building, which in Ireland you would have to do to comply with building regulations. Up until recently LEED asked projects to do energy modelling based on ASHRAE standards to demonstrate compliance. However, LEED now allows BREEAM equivalency to award energy credits meaning the BER approach can be recognised. Both methodologies are trying to adapt more to international markets and are constantly evolving, sometimes even borrowing ideas from each other to make improvements.   (See Article from Engineers Ireland on BREEAM ).

LumenMeasurement of the Output of light from a Lamp.

LuminaireApparatus or fitting that holds an LED/LED module/Lamp.

LuxMeasurement of the light received at a point (1 Lux = 1 Lumen per square meter).

MHMounting Height.

PhotocellA device which switches off the Luminaire during day time.  A 35/18 Photocell will switch on the light at 35 Lux and off again at 18 Lux.

RaSee CRI above.

TransformerElectrical component used to change 230v electrical supply to other voltages (usually 12v) which some luminaires require to operate.

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