Massachusetts Plumbers Journeyman Practice Exam

The correct choice for this question is based on the installation requirements specific to ABS (Acrylonitrile Butadiene Styrene) DWV (Drainage, Waste, and Vent) pipes. Expansion joints are typically not required in ABS-DWV systems because these pipes are designed to handle the thermal expansion and contraction that can occur due to temperature changes.

ABS is a lightweight, durable material that is relatively stable when exposed to heat, making it less susceptible to issues that might necessitate the use of expansion joints. Instead, proper assembly techniques and allowances for movement are generally sufficient to accommodate any expansion or contraction without the added complexity of expansion joints.

In contrast, other types of joints such as compression, flexible, and flare joints may have specific applications where they are necessary for the proper sealing and movement in plumbing systems. For instance, compression joints may be used in connection points where a tight seal is critical. Therefore, they can still be relevant when working with ABS pipes in certain contexts.