The Heat Exchange Institute (HEI) is a non-profit trade association committed to the technical advancement, promotion, and understanding of a broad range of utility and industrial-scale heat exchange and vacuum apparatus. The primary purpose of HEI is to develop and publish standards which advance the technology, increase the efficiency, and promote the use of heat exchange and vacuum apparatus.

The National Board of Boiler and Pressure Vessel Inspectors was created in 1919 to promote greater safety to life and property through uniformity in the construction, installation, repair, maintenance, and inspection of pressure equipment.