What does purple primer do in PVC joints and is it required?

• A. It colors the pipe
• B. It cleans and helps cement joints and is required by TCEQ
• C. It lubricates joints
• D. It seals leaks

Answer: (B)

Purple primer prepares PVC surfaces for a solvent-weld joint by cleaning them and softening the plastic so the cement can form a strong bond. This step helps ensure a leak-free, durable joint. In many codes, including TCEQ, the primer is required before applying solvent cement on PVC joints, so skipping it can mean noncompliance and a weak connection. The purple color isn’t the main purpose—it's a code indicator that primer was used—but the primer itself is essential for proper bonding. It isn’t a lubricant, and it doesn’t seal leaks by itself; the cement seals the joint, but primer is needed to make that seal reliable.