609.12 Pipe Insulation — 2025 California Plumbing Code

Insulation of domestic hot water piping shall be in accordance with Section 609.12.1 and Section 609.12.2.

609.12.1 Insulation Requirements. Domestic hot water piping shall be insulated. 609.12.2 Pipe Insulation Wall Thickness. Hot water pipe insulation shall have a minimum wall thickness of not less than the diameter of the pipe for a pipe up to 2 inches (50 mm) in diameter. Insulation wall thickness shall be not less than 2 inches (51 mm) for a pipe of 2 inches (50 mm) or more in diameter. Exceptions: (1) Piping that penetrates framing members shall not be required to have pipe insulation for the distance of the framing penetration. (2) Hot water piping between the fixture control valve or supply stop and the fixture or appliance shall not be required to be insulated. 609.12.3 California Energy Code Pipe Insulation Requirements. [CEC] See California Energy Code Sec- tions 150.0(j)2 and 120.3(c) for pipe insulation require- ments based on fluid temperature and pipe diameter – for domestic hot water piping. The California Energy Code requires that piping that penetrates metal framing shall use grommets, plugs, wrapping or other insulating mate- rial to assure that no contact is made with the metal fram- ing. The California Energy Code also requires that insulation shall abut securely against all framing mem- bers, and places conditions on when installed wall or attic insulation that surrounds installed piping can be consid- ered to provide pipe insulation meeting requirements.