Arizona Plumbing Practice Exam

Which of the following is not allowed in building interior plumbing (water distribution)?

1. PVC

2. Copper

3. PEX

4. CPVC

The correct answer is: PVC

In the context of building interior plumbing, particularly for water distribution systems, specific materials are regulated by plumbing codes, which are put in place to ensure safety and effectiveness. PVC (Polyvinyl Chloride) is typically not permitted for hot water distribution in most plumbing codes, including those in Arizona. This is due to its susceptibility to warping and becoming structurally compromised when exposed to high temperatures, making it unsuitable for applications that require a material to withstand hot water. Commodity choices like copper, PEX (cross-linked polyethylene), and CPVC (chlorinated polyvinyl chloride) are widely accepted materials due to their durability and temperature resistance. Copper is well-known for its longevity and resistance to corrosion. PEX offers flexibility and ease of installation, making it popular in residential plumbing. CPVC, on the other hand, can handle hot water applications and is also resistant to corrosion. Thus, the choice of PVC as not being allowed for interior water distribution systems is grounded in its operational limitations when dealing with hot water, which is a critical factor in plumbing applications.