Double sanitary tea fittings may be used when they receive the discharge from which of the following fixtures? Assume the fixtures are separated by 16 inches horizontally.

Using double sanitary tea fittings for back-to-back water closets is not advisable due to the significantly different waste discharge characteristics. Water closets generate larger volumes of waste and require dedicated venting to avoid blockage issues, thus necessitating separate drainage systems rather than a shared fitting.

Side-by-side water closets also cannot utilize double sanitary tea fittings effectively. This arrangement leads to complications in drainage due to the close proximity of the fixtures and the need for individual venting, which would not be accommodated by a shared fitting designed for sinks.

While fixtures with pumping action may necessitate specialized drainage solutions, they cannot universally rely on double sanitary tea fittings. The pumping action alters the flow dynamics, thereby requiring specific configurations that account for the unique discharge characteristics of each fixture type.