Lamp reference

The multitude of lamp types, their performance, light colours, base designs and other properties are impossible to manage. Company-specific references for similar and compatible lamps deviate from each other. However, practical applications demand a consistent lamp reference system which captures the most important cross-company lamp characteristics.

The German electric lighting trade association Zentralverband der Elektrotechnik- und Elektronikindustrie (ZVEI) has developed a lamp reference system called LBS which predominantly lists lamps according to their luminaire-relevant properties; it was last updated in 2010. This system has been introduced widely in the German but also in the European luminaire industry since it enables short references sufficient to identify lamp types. The LBS system – or parts of it – is often used as a luminaire order code component, e.g. TC (tubeform compact) for compact fluorescent lamp luminaires.

The LBS consists of three system blocks. The first system block specifies the light generation type, e.g. “H” for high pressure; the second system block indicates the medium used to generate light, e.g. “M” for mercury. This leads to a classification in 7 groups:

  1. General-use incandescent lamps

  2. Halogen lamps

  3. High-pressure discharge lamps HM (mercury vapour)

  4. High-pressure discharge lamps HI (metal halide)

  5. High-pressure discharge lamps HS (sodium vapour)

  6. Low-pressure discharge lamps LM (mercury vapour)

  7. Low-pressure discharge lamps LS (sodium vapour)

LED lamps as retrofits for incandescent lamps, halogen lamps or fluorescent lamps are not considered in the LBS system.

The third system block fundamentally expresses the shape of the bulb, e.g. “T” (tube) for tubular lamps. Additional reference amendments are determined in the LBS catalogue (see

Fluorescent lamps are low-pressure mercury discharge lamps with reference “LM” (low pressure, mercury), followed by the bulb shape specification.


LM T26 refers to a fluorescent luminaire with 26 mm tube diameter which is also referred to as T8 internationally. According to LBS, T5 lamps are referred to as T16. Older T12 lamps with 38 mm diameter are referred to as T38 according to LBS. For convenience, LM is mostly omitted.

Other information such as lamp wattage, light colour and base reference can be added to this fundamental reference.

At international level, the lamp reference system ILCOS (International Lamp Code System) was introduced, which is described in the international specification IEC 61231:2010 + A1:2013 and has e.g. been published as German standard in DIN EN 61231 [91]. In the catalogues of internationally operating lamp manufacturers, ILCOS references are contrasted with company-specific lamp references in the form of a translation list.

ILCOS captures nearly all lamp properties.This leads to reference lengths which are very difficult to handle in practice due to description clarity alone and can therefore not be used as an ordering component for the luminaire in question. Therefore, short (ILCOS L), extended short (ILCOS LE) or standard references (ILCOS D) are also possible as full lamp references.

The structure of ILCOS references is defined in DIN EN 61231 [91] for the following lamp types:

  1. Incandescent lamps

  2. Halogen lamps

  3. Fluorescent lamps

  4. High-pressure sodium vapour lamps

  5. Low-pressure sodium vapour lamps

  6. High-pressure mercury vapour lamps

  7. Metal halide lamps

  8. LED modules and lamps

  9. Lamps/starters for specific applications

Example 1

According to ILCOS D, a tubular fluorescent lamp T8 58 W with light colour 840 is referenced as follows: FD-58/40/1BE- G13-26/1500.

In which:


double ended fluorescent lamp


wattage 58 W


light colour 4,000 K


for Ra from 80 to 89


starting behaviour: external starter, with pre-heating


base reference


tube diameter 26 mm


length 1,500 mm

Example 2

According to ILCOS D, a drop-shaped E14 LED retrofit lamp with a power consumption of 6 W and light colour 840 is referenced as follows: DRP-6/30/1B-E14-45.

In which:


retrofit LED lamp with integrated control gear unit


drop-shaped (as the lamp requiring replacement)


wattage 6 W


light colour 3,000 K


for Ra from 80 to 89


base reference


nominal diameter of the lamp’s construction (requiring replacement)