NEN EN 1861 : 1998

Foreword
Introduction
1 Scope
2 Normative references
3 Definitions
4 Classification, information content and
    presentation
5 Layout of diagrams
6 Selection of graphical symbols
Annex A (informative) Examples of flow diagrams for
refrigerating systems
Annex B (informative) Letter code, general symbols and
examples of measurement and control symbols
Annex C (informative) Bibliography

Defines symbols and drawing rules for system flow diagrams and piping and instrument diagrams for application to refrigerating systems, including heat pumps. Not applicable to refrigerating systems where the heat is extracted by an electrical circuit, such as Peltier-effect.