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ILCOS International Lamp Code System
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ILCOS International Lamp Code System

ILCOS is the "International Lamp Coding System" according to IEC 1231, which is described in the international specification IEC TS 61231 from 1999 and published e.g. in DIN 49805 as a German standard.

The structure of ILCOS designations applies to:

  • Incandescent lamps
  • Halogen incandescent lamps
  • Fluorescent lamps
  • High-pressure sodium lamps
  • Low-pressure sodium vapor lamps
  • High-pressure mercury vapor lamps
  • Metal halide lamps
  • Lamps/starters for special applications

ILCOS goals

  • to improve communication across the different lamp types
  • help with interchangeability and compatibility
  • improve clarity between international standards and manufacturer documentation
  • to enable correct lamp replacement
  • to be used as an additional marking on the luminaire
  • replace national and regional marking systems

The structure of ILCOS

The first letter stands for the lamp category:

 V = automotive lamps

 F = fluorescent lamps

 I = conventional incandescent lamps

The next letters stand for the details:

Lamp shape, light color, design features (with one slash if applicable, other features with two slashes).

 -

 Numbers for indication of wattage

-

 Numbers to indicate voltage

-

 Numbers to indicate lamp socket

-

 Numbers indicating the dimensions of the lamp

The different ILCOS versions

The ILCOS marking system makes it possible to compare and thus exchange lamps from different manufacturers - company-specific lamp designations are compared in a translation list.

ILCOS covers almost all lamp characteristics. In practice, this leads to a length of designations that is difficult to handle. Therefore there are three versions for the detail of the designations:

ILCOS L consists only of the letter part. A medium version ILCOS D consisting of the letter and number part is so detailed that the user can also exchange lamps from different manufacturers. The complete specification as ILCOS T contains the complete designation part and a standardization part, thus all specifications required for the application.

ILCOS Example

A rod-shaped T8 fluorescent lamp 58 W of light color 840 is designated according to ILCOS D as follows.

"FD-58/40/1B-E-G13-26/1500" - the meaning in detail:

FD double-ended lamp

58 Power

58 W

40 Light color

4000 K

1B for Ra from 80 to 89

E starting behavior: external starter, with preheating

G13 Base designation

26 Tube diameter 26 mm 1500 Length 1500 mm