IEC 61355

The standard IEC 61355-1 Classification and designation of documents for plants, systems and equipment describes rules and guidelines for the uniform classification and identification of documents based on their characteristic content of information.

It is applied for all documents within the life cycle of a technical products like plants, systems or equipment. It also includes non-technical documents. The main application is the construction, erection and operation of industrial plants where the number of documents of all engineering disciplines may sum up to some 100,000 documents.

During 2024, the new cross-standard ISO/IEC 81355 will be published and will replace the second edition of IEC 61355-1 published in 2008. The new standard will switch from "document classification" to "information classification" methods.

Classification code
The standard provides with the document kind classification code (DCC) a structured letter-code for the classification of any kind of document.

A public access database IEC 61355 DB is available in order to facilitate the individuation of the correct code to be applied to a document

The document kind classification code consists of three code-letters A1, A2, A3, with the prefix "&".
 * A1 Letter code for technical area class
 * A2 Letter code for main class
 * A3 Letter code for sub-class

The letter code A1 is optional, if all documents are from the same technical area. The letter codes A2 and A3 are identical for all technical areas.

Technical Areas
The technical areas are:

Classes
The main classes are:

Main classes and subclasses
Table of main classes and subclasses Source: IEC 61355-1