Overview
ISO 2145:1978 - Documentation: Numbering of divisions and subdivisions in written documents - defines a simple, language-independent system for numbering sections, subsections and lower-level divisions in manuscripts, printed works, books, journal articles, instructions for use and standards. The standard promotes the use of Arabic numerals and dot-separated numbering to clarify sequence, hierarchy and interrelations of parts, to simplify search and retrieval, to enable precise citation of parts, and to facilitate internal cross-references.
Key Topics
- Scope and purpose
- Applies to all kinds of written documents (manuscripts, printed works, books, journal articles, instructions, standards).
- Numbering is advised when it clarifies order, importance and relations of parts, and when it simplifies retrieval and citation.
- Numbering format
- Use Arabic numerals for all division numbers.
- Main (first-level) divisions are numbered continuously starting at 1.
- Subdivisions at any subsequent level are numbered continuously within their parent division.
- Separate level numbers with a point (dot) (e.g., 1.1, 2.1.2, 1.3.1.21).
- Do not add a trailing point after the final number.
- Special cases
- A digit 0 (zero) may be assigned to an introductory part (preface, introduction) at any level.
- The system can be extended to many levels, but ISO 2145 recommends limiting the number of levels so numbers remain easy to read, find and cite.
- Citations and in-text use
- Division numbers are cited in text using the numeric form (e.g., “see 9.2” or “3rd paragraph of 1.1.2.2”).
- When spoken or enunciated, the dots are not pronounced (examples in the standard: 2.11 pronounced “two eleven”; 2.27 pronounced “two twenty-seven”).
Applications
- Authors, editors and publishers preparing structured documents, technical reports, academic books and standards.
- Technical writers, documentation managers and information architects seeking consistent , easier navigation and reliable internal referencing.
