CSLB C-46 Solar ContractorElectrical and Plumbing CodesHard
A solar contractor is installing a non-potable closed-loop solar thermal system for space heating. The system uses a heat transfer fluid that is toxic if ingested. According to the California Plumbing Code (CPC), what is the minimum required separation distance between the non-potable heat transfer fluid lines and any potable water lines they cross?
- A3 inches (75 mm) vertical, 6 inches (150 mm) horizontal
- B12 inches (300 mm) vertical, 12 inches (300 mm) horizontal
- C1 inch (25 mm) vertical, 6 inches (150 mm) horizontal
- D6 inches (150 mm) vertical, 12 inches (300 mm) horizontal
Show answer & explanationAnswer & explanation
Correct answer: D. 6 inches (150 mm) vertical, 12 inches (300 mm) horizontal
CPC Section 603.2.1, which references UPC 603.2.1 (Protection of Potable Water Supply), specifically addresses cross-connection control. For non-potable systems containing toxic fluids, the code requires a minimum vertical separation of 6 inches (150 mm) and a minimum horizontal separation of 12 inches (300 mm) where these lines cross potable water lines. This is a critical measure to prevent contamination.
Why the other options are wrong
- A. These separations are insufficient for toxic non-potable lines crossing potable water lines.
- B. While safer, 12 inches vertical is not the minimum specified by code; 6 inches vertical is the minimum.
- C. These separations are insufficient for toxic non-potable lines crossing potable water lines.
Toxic Non-Potable/Potable Cross-Separation
CPC requires a minimum 6-inch vertical and 12-inch horizontal separation between toxic non-potable fluid lines and potable water lines they cross.
- Prevents cross-contamination of drinking water.
- Applies to toxic heat transfer fluids.
- Referenced in CPC Section 603.2.1.
Memory trick: Toxic Pipes: Six Up, Twelve Across for Potable Peace.