About 81346-2 (existing edition)

 

OBS! The new 2017 edition will launch soon. See the new letter codes here.

A letter codes enables classification of objects. The letter codes, which are common to all technical branches, come from ISO/IEC 81346-2 table 1.

There are in total 18 classes, identified by the following letter codes:

A

Two or more purposes or tasks

B

Converting an input variable into a signal for further processing

C

Storing of energy, information or material

E

Providing radiant or thermal energy

F

Direct protection from dangerous or unwanted conditions

G

Initiating a flow of energy or material

H

Producing a new kind of material or product

K

Processing signals or information

M

Providing mechanical energy for driving purposes

P

Presenting information

Q

Controlled switching or varying a flow of energy, of signals or of material

R

Restricting or stabilizing motion or a flow of energy, information or material

S

Converting a manual operation into a signal for further processing

T

Conversion of energy maintaining the kind of energy

U

Keeping objects in a defined position

V

Processing (treating) of material or products

W

Guiding or transporting from one place to another

X

Connecting objects

Example with one letter code

As you can see, the letter code C means ‘Storing of energy, information or material’. This means that for example a storage tank (storage of liquids) is classified with a C, and a capacitor (storage of energy) also is classified with a C. Hereby, common letter codes applies across technical border lines.

Example with two letter codes

In ISO/IEC 81346-2 table 2 is an expansion of table 1, and thereby a ‘two letter code’ classification is available. The two letter codes limits the classification span, and thereby makes the classification more precise if desirable, for example:

  • BF Flow meter, gas meter, water meter
  • CP Hot water accumulator, ice tank
  • ET Nuclear reactor
  • FL Safety valve
  • FR Cathodic protection
  • GC Solar cell
  • HX Reactor
  • PG Voltmeter, thermometer
  • PJ Horn, loudspeaker

Please see 81346-2 table 1 and 2 for full reference (will be included in the new guide as well).