Historical
ANSI/ASHRAE Standard 134-2005
Graphic Symbols for Heating, Ventilating, Air-Conditioning, and Refrigerating Systems
This standard covers graphic symbols for heating, ventilating, air-conditioning, and refrigerating systems and equipment, including related controls. It identifies graphic symbols by name, configuration, and description. The graphic symbols in this standard are intended for use in manual drawings and drawings produced by computer-aided drafting (CAD).
American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. [ashrae]