System components must be protected from freezing at what ambient temperature?

System components need to be protected from freezing at the lowest ambient temperature that can be reasonably expected in the location where the system is installed. This is crucial because if the temperature drops to a level below the freezing point, the fluids in the system can freeze, expand, and potentially cause damage to pipes, fittings, and other components.

By focusing on the lowest expected temperatures, designers and installers can take necessary precautions, such as insulating piping or using heating elements, to ensure the integrity and functionality of the HVAC or plumbing systems throughout the coldest part of the year. This proactive approach is essential in building codes and mechanical standards to ensure long-term system reliability and safety.