This SAE Aerospace Recommended Practice (ARP) provides symbols to schematically represent aerospace vehicle environmental system components on functional flow schematic drawings and graphical computerized output. The symbols are for use on simplified diagrams that provide basic information about an environmental system.

Symbols are provide to represent basic types of components used in environmental systems. Simple variations of basic symbol types are provided. Words on the schematic diagram, special symbol codes, or symbols that combine basic symbol types can be used to augment the basic symbols when appropriate. Special or combined symbols not contained in this document should be defined on the schematic diagram.