A transition coupling may be used to _________________________________________________.

A transition coupling is specifically designed to connect dissimilar materials, ensuring a proper and secure connection where different types of piping meet. In this case, connecting a PVC schedule 40 tub waste and overflow to a metallic waste pipe is a common application for a transition coupling. This type of fitting accommodates the differences in material properties and diameters, providing a reliable seal that prevents leaks.

When connecting PVC to metal, a transition coupling often includes features such as rubber gaskets or O-rings to absorb variations in expansion and contraction between the two materials, making it suitable for plumbing systems that require compatibility between various plumbing materials.

Using a transition coupling in this context adheres to plumbing code requirements by ensuring that the joint remains watertight and structurally sound throughout its life cycle.