The answer is in compliance with DIM 2 (Domestic Implementation Measure 2) I have covered this broadly in a previous blog post but this is specifically aimed at GU10 lamps.
There has been an explosion of LED GU10 suppliers that have entered the market, the reason being that 77% of all retrofit LED lamps are GU10. These lamps are designed to replace 50w GU10 Halogen lamps many of which do not meet the performance either mechanically or electrically of a 50w Halogen GU10. Because of this it was decided that in the release of DIM 2, requirements should be set to ensure that any lamps that are put on the market meet criteria that will ensure they are directly equivalent to a Halogen GU10.
Light output is being expressed in a different way. Traditionally we have always associated Wattage with light output but with new technologies giving improved efficacies (the amount of light per Watt of power that you get from a light source) we express light in terms of Lumens ie the amount of light a given source emits.
As an example a 5w LED GU10 can give the same light output as a 50w Halogen GU10 ie 350 Lumens , it is because of this that we now need to look at the Lumen output of the lamp instead of the wattage of the lamp to gauge how much light it will emit. The amount of light (Lumens) that a bulb gives will now be clearly marked on the packaging of the lamp.
For an LED GU10 reflector lamp to be equivalent to a 50w Halogen it has to hit the magical figure of 350 Lumens, but in a 90 degree cone , the useful light that it gives out.
The following functionality criteria also has to be met.
1) After 6000 hours burning there has to be 90% or greater lamps surviving.
2) After 6000 hours burning the Lumen decay must not have exceeded 20% ie at 6000 hours each lamp must not have lost more than 20% of its original Light Output
3) Colour rendering CRI has to be greater than 80 . CRI is the quality of light expressed on a scale of 1-100 , 1 being monochromatic or a single colour, 100 being perfect or the light that we see when we are outdoors.
Information displayed on an LED Lamp
The following information now needs to be displayed on the lamp itself
1) Lumen Output – Lumens (lm)
2) Colour temperature – Kelvin (K)
3) Beam Angle – Degrees
4) All other safety information such as power and voltage
Information to be displayed on Packaging
1) Light Output
2) Lamp Life
3) Colour temperature
4) Number of switching cycles before failure
5) Warm up time to 60% of full light output
6) A warning if the lamp cannot be dimmed
7) Lamp dimensions
8) Beam angle
9) If the lamp is designed to replace a filament lamp and its dimensions differ, a drawing clearly showing the differences.
In addition to this the equivalent filament lamp may be shown on the packaging as long as the light output is no lower than the equivalent that it is replacing. The same is applicable if you want to show the equivalent wattage to the filament source that the LED is replacing.