New Mexico Pipe Fitter Journeyman (JPF) Practice Exam

What is the main purpose of using joint compound in piping?

1. To enhance aesthetics

2. To prevent leaks

3. To provide insulation

4. To increase pressure

The correct answer is: To prevent leaks

The primary purpose of using joint compound in piping is to prevent leaks. Joint compound, also known as pipe dope or thread sealant, serves as a lubricant and sealant that fills in any gaps or imperfections in the threaded connections of pipes. When applied to the threads before joining two pieces of pipe, it creates a tighter seal as the threads engage with one another. This prevents the escape of fluids—whether liquids or gases—through the joint, ensuring that the system operates efficiently and safely. While enhancing aesthetics, providing insulation, and increasing pressure may be considerations in other contexts, they are not the primary functions of joint compound in piping systems. The focus on leak prevention is crucial in situations where pressurized fluids are involved, as leaks can lead to system inefficiencies, damage, and potentially hazardous situations. Thus, using joint compound effectively helps maintain the integrity and reliability of plumbing and piping installations.