International Classification of Standards (ICS)
The ICS (International Classification for Standards) is intended to serve as a structure for catalogues of international, regional and national standards and other normative documents, and as a basis for standing-order systems for international, regional and national standards. It may also be used for classifying standards and normative documents in databases, libraries, etc. The ICS should facilitate the harmonization of information and ordering tools such as catalogues, selective lists, bibliographies, and databases on magnetic and optical media, thus promoting the worldwide dissemination of international, regional and national standards and other normative documents. By clicking on the general number of the ICS code "43" you can access the hierarchical classification which consists of three levels. By clicking the number of these levels you can search standard by ICS code, like 43.040.20. More on ICS can be found on https://www.iso.org/publication/PUB100033.html