Code Cycle: 2016 & 2019 Residential Standards
Reference: CalCERTS New Construction Training Manual Chapter 5, Section 5
Form: CF3R-PLB-21 Multi-Family Central Hot Water Distribution Systems
Form: CF3R-PLB-22 Single Dwelling Unit Hot Water Distribution Systems
HERS Verified Mandatory Pipe Insulation Requirements for all Hot Water Distribution Systems
Pipe insulation shall fit tightly to the pipe and all elbows and tees shall be fully insulated. No piping should be visible due to insulation voids with the exception of the last segment of piping that penetrates walls and delivers hot water to the sink, appliance, etc.
150.0(j)2 All domestic hot water piping shall be insulated as specified in Section 609.11 of the California Plumbing Code. In addition, the following piping conditions shall have a minimum insulation wall thickness of 1 inch or a minimum insulation R-value of 7.7:
- The first 5 feet of cold water pipes from the storage tank.
- All hot water piping with a nominal diameter between ¾ inch and 1 inch.
- All hot water piping with a nominal diameter less than ¾ inch that is:
- Associated with a domestic hot water re-circulation system;
- From the heating source to the kitchen fixtures;
- From the heating source to a storage tank or between storage tanks; or
- Buried below grade.
RA3.6.2: In addition, all piping below grade must be installed in a waterproof and non-crushable casing or sleeve that allows for installation, removal and replacement of the enclosed pipe and insulation. The internal cross-section or diameter of the casing or sleeve shall be large enough to allow for insulation of the hot water piping.
The installation shown in Figure 5-4 below would not meet the installation requirements since they are not insulated. In addition, the hot and cold water lines are not separated. Heat transfer will occur, resulting in energy loss and causing condensation on the cold water line.
Piping Exempt from the Mandatory Insulation Includes:
- Piping that penetrates framing members. This piping is not required to have insulation where it penetrates the framing. However, if the framing is metal, then some insulating material must prevent contact between the pipe and the metal
- If in exterior walls, the cavity insulation completely surrounds the pipe with at least 1 inch of insulation.
- In attics and crawlspaces, the insulation shall completely surround the pipe with at least 1 inch of insulation and the pipe shall be completely covered with at least 4 inches of insulation further away from the conditioned space. Piping may not be placed directly in contact with sheetrock and then covered with insulation to meet this requirement.
Other Installation Information:
- No insulation should be installed closer than 6 inches from the flue. If possible, bend the pipe away from the flue. Otherwise, it may be necessary to stop pipe insulation short of the storage tank.
- All pipe insulation seams should be
- Installed piping may not be located in supply or return air plenums. (CBC)
- Hot and cold water piping, when installed in parallel runs, should be at least 2 inches
- If a firewall interrupts the first 5 feet of pipe, the insulation may be interrupted at the wall and continued on the other
- Insulation for pipe elbows should be mitered and insulation for tees should be notched.
Where insulation is required as described above, 1 inch of insulation is typically required. This requirement applies to domestic hot water pipe (above 105° F) when the pipe diameter is 1 inch or smaller, the water temperature is between 105°F and 140°F, and the insulation conductivity between 0.22 and 0.28 BTU-in/hr-ft²-°F (typical of cellular foam pipe insulation material). One and one-half inch insulation is required on pipes greater than 1 inch. For other situations refer to Table 120.3-A below.