‘luminous flux’ (Φ) means the quantity derived from radiant flux (radiant power) by evaluating the radiation in accordance with the spectral sensitivity of the human eye. Without further specification it refers to the initial luminous flux;

‘initial luminous flux’ means the luminous flux of a lamp after a short operating period;

useful luminous flux (Φ_use) means the part of the luminous flux of a lamp falling within the cone used for calculating the lamp’s energy efficiency in point 1.1 of Annex III;

‘luminous intensity’ (candela or cd) means the quotient of the luminous flux leaving the source and propagated in the element of solid angle containing the given direction, by the element of solid angle;

‘beam angle’ means the angle between two imaginary lines in a plane through the optical beam axis, such that these lines pass through the centre of the front face of the lamp and through points at which the luminous intensity is 50 % of the centre beam intensity, where the centre beam intensity is the value of luminous intensity measured on the optical beam axis;

‘chromaticity’ means the property of a colour stimulus defined by its chromaticity coordinates, or by its dominant or complementary wavelength and purity taken together;

‘correlated colour temperature’ (Tc [K]) means the temperature of a Planckian (black body) radiator whose perceived colour most closely resembles that of a given stimulus at the same brightness and under specified viewing conditions;

‘colour rendering’ (Ra) means the effect of an illuminant on the colour appearance of objects by conscious or subconscious comparison with their colour appearance under a reference illuminant;

‘colour consistency’ means the maximum deviation of chromaticity coordinates (x and y) of a single lamp from a chromaticity centre point (cx and cy), expressed as the size (in steps) of the MacAdam ellipse formed around the chromaticity centre point (cx and cy);

‘lamp lumen maintenance factor’ (LLMF) means the ratio of the luminous flux emitted by the lamp at a given time in its life to the initial luminous flux;

‘lamp survival factor’ (LSF) means the defined fraction of the total number of lamps that continue to operate at a given time under defined conditions and switching frequency;

‘lamp lifetime’ means the period of operating time after which the fraction of the total number of lamps which continue to operate corresponds to the lamp survival factor of the lamp under defined conditions and switching frequency. For LED lamps, lamp lifetime means the operating time between the start of their use and the moment when only 50 % of the total number of lamps survive or when the average lumen maintenance of the batch falls below 70 %, whichever occurs first;

‘lamp start time’ means the time needed, after the supply voltage is switched on, for the lamp to start fully and remain alight;

‘lamp warm-up time’ means the time needed after start-up, for the lamp to emit a defined proportion of its stabilised luminous flux;

‘power factor’ means the ratio of the absolute value of the active power to the apparent power under periodic conditions;

‘lamp mercury content’ means the mercury contained in the lamp;

‘rated value’ means the value of a quantity used for specification purposes, established for a specified set of operating conditions of a product. Unless stated otherwise, all requirements are set in rated values;

‘nominal value’ means the value of a quantity used to designate and identify a product;

‘no-load mode’ means the condition of a lamp control gear where it is connected to the supply voltage and where its output is disconnected in normal operation from all the primary loads by the switch intended for this purpose (a faulty or missing lamp, or a disconnection of the load by a safety switch is not normal operation);

‘standby mode’ means a mode of lamp control gear where the lamps are switched off with the help of a control signal under normal operating conditions. It applies to lamp control gear with a built-in switching function and permanently connected to the supply voltage when in normal use;

‘control signal’ means an analogue or digital signal transmitted to the control gear wirelessly or wired either via voltage modulation in separate control cables or via modulated signal in the supply voltage;

‘standby power’ means the power consumed by the lamp control gear in standby mode;

‘no-load power’ means the power consumed by the lamp control gear in no-load mode;

‘switching cycle’ means the sequence of switching the lamp on and off at set intervals;

‘premature failure’ means when a lamp reaches the end of its life after a period in operation which is less than the rated life time stated in the technical documentation;

‘anti-glare shield’ means a mechanical or optical reflective or non-reflective impervious baffle designed to block direct visible radiation emitted from the light source of a directional lamp, in order to avoid temporary partial blindness (disability glare) if viewed directly by an observer. It does not include surface coating of the light source in the directional lamp;

‘compatibility’ means that when a product is intended to be installed in an installation, inserted into another product or connected to it through physical contact or wireless connection,

1. (i)

   it is possible to perform the installation, insertion or connection; and

2. (ii)

   shortly after starting to use them together, end-users are not led to believe that any of the products has a defect; and

3. (iii)

   the safety risk of using the products together is not higher than when the same products taken individually are used in combination with other products.