Piping for embedment in concrete or gypsum materials shall be standard-weight steel pipe, copper tubing, cross-linked polyethylene/aluminum/cross-linked polyethylene (PEX-AL-PEX) pressure pipe, chlorinated polyvinyl chloride (CPVC), polybutylene, cross-linked polyethylene (PEX) tubing or polypropylene (PP) with a minimum rating of 100 psi at 180°F (690 kPa at 82°C).
Exception: Insulation shall not be required in engineered systems where it can be demonstrated that the insulation will decrease the efficiency or have a negative effect on the installation.
In suspended floor applications, insulation shall be installed in the joist bay cavity serving the heating space above and shall consist of materials having a minimum R-value of 11.
A thermal break consisting of asphalt expansion joint materials or similar insulating materials shall be provided at a point where a heated slab meets a foundation wall or other conductive slab.
Insulating materials used in thermal barriers shall be installed so that the manufacturer's R-value mark is readily observable upon inspection.
Piping joints that are embedded shall be installed in accordance with the following requirements:
- Steel pipe joints shall be welded.
- Copper tubing shall be joined with brazing material having a melting point exceeding 1,000°F (538°C).
- Polybutylene pipe and tubing joints shall be installed with socket-type heat-fused polybutylene fittings.
- CPVC tubing shall be joined using solvent cement joints.
- Polypropylene pipe and tubing joints shall be installed with socket-type heat-fused polypropylene fittings.
- Cross-linked polyethylene (PEX) tubing shall be joined using cold expansion, insert or compression fittings.
Piping or tubing to be embedded shall be tested by applying a hydrostatic pressure of not less than 100 psi (690 kPa). The pressure shall be maintained for 30 minutes, during which all joints shall be visually inspected for leaks.