Concealed slip joint connections require an access panel not less than _____ inches in the smallest dimension.

The requirement for an access panel in concealed slip joint connections is important for maintenance and repairs. Access panels provide a way for plumbers to reach hidden plumbing connections without having to dismantle walls or ceilings, which can save time and reduce damage during repair work.

The correct size for the access panel is stipulated to be no less than 12 inches in the smallest dimension. This size is practical, allowing sufficient space for a plumber to see and manipulate any necessary pipes or joints. If the panel were smaller, it would be challenging to access the connections effectively, which could hinder repairs or regular maintenance.

Larger options like 18 or 20 inches are not mandated by code, although they may offer additional access room; they are not the minimum requirement. This emphasizes that while access is necessary, it does not need to be excessively large to be functional. Therefore, having the smallest dimension of the access panel set at 12 inches ensures both compliance with plumbing codes and functionality for maintenance tasks.