CSLB C-46 Solar ContractorSolar Thermal System InstallationEasy
A solar thermal system installer is connecting a new collector array to the existing piping. The local plumbing code specifies that all piping within 5 feet of the collector must be rated for continuous exposure to temperatures up to 350°F (177°C) and pressure up to 150 psi. Which of the following pipe materials is most appropriate for this application?
- ACPVC (Chlorinated Polyvinyl Chloride)
- BType M Copper
- CPEX (Cross-linked Polyethylene)
- DPVC (Polyvinyl Chloride)
Show answer & explanationAnswer & explanation
Correct answer: B. Type M Copper
Type M copper, while thinner than Type L or K, is still suitable for the specified temperature and pressure ratings in solar thermal applications near the collector. PVC, PEX, and CPVC have significantly lower temperature limits.
Why the other options are wrong
- A. CPVC has a maximum operating temperature typically around 200°F (93°C) for pressure applications, which is too low.
- C. PEX has a maximum operating temperature typically around 200°F (93°C), which is too low for collector proximity.
- D. PVC has a maximum operating temperature typically around 140°F (60°C), which is too low.
Solar Thermal Piping Materials
Materials used for solar thermal piping must withstand high temperatures and pressures, especially near collectors, and be compatible with heat transfer fluids.
- Copper is a common choice due to high temperature and pressure tolerance.
- Plastic pipes (PVC, PEX, CPVC) have lower temperature limits and are generally unsuitable for collector loops.
- Stainless steel or specialized high-temperature flexible tubing may also be used.
Memory trick: High heat, high pressure, copper's the treasure.