Uniform Solar Energy and Hydronics Code

Designated as an American National Standard, the Uniform Solar, Hydronics and Geothermal Code (USHGC) is a model code developed by IAPMO to govern the installation and inspection of solar energy, hydronic heating/cooling systems, and geothermal energy systems as a means of promoting the public's health, safety and welfare. The USHGC is developed using the American National Standards Institute's consensus development procedures.

Source: Wikipedia — Uniform Solar Energy and Hydronics Code (CC BY-SA 4.0)