Massachusetts Plumbers Journeyman Practice Exam

What should every mechanical joint in cast iron pipe or ductile iron pipe be made with?

1. Welded collar

2. Compression fitting

3. Flanged collar, rubber ring gasket, securing bolts

4. Threaded connection

The correct answer is: Flanged collar, rubber ring gasket, securing bolts

The correct choice is to use a flanged collar, rubber ring gasket, and securing bolts at every mechanical joint in cast iron or ductile iron pipe. This method provides a reliable and effective seal that accommodates the thermal expansion and contraction of the materials while ensuring a strong connection that can withstand internal pressures. Using a flanged collar allows for easy disassembly and maintenance, which is vital in plumbing systems, where repairs may be necessary. The rubber ring gasket serves as a flexible barrier that helps prevent leaks and maintains the integrity of the connection, even under varying conditions. Securing bolts provide the necessary clamping force to keep the joint tight and leak-proof. Other connection methods may not provide the same level of flexibility, maintenance ease, or sealing effectiveness that is necessary in mechanical joints for these types of pipes, making the selected option the most appropriate choice for this application.