In a drainage system, under what circumstance can a T fitting be utilized?

The use of a T fitting in a drainage system is primarily to connect pipes at an angle that allows for the efficient flow of waste. In the context of connecting a vent pipe, a T fitting is essential because it allows a vent to connect to a horizontal drainage line without significantly disrupting the flow of the waste. Vent pipes are integral in providing air to the drainage system, preventing the formation of vacuum or pressure issues, and ensuring that waste can flow smoothly.

The design of the T fitting enables the vent to rise vertically, which is a common requirement in plumbing codes to ensure proper venting. This vertical component of the vent connection is important for the overall health of the drainage system.

In contrast, while T fittings can be used for connecting waste pipes, they are not the ideal choice for vertical connections due to potential issues with waste flow and blockage. Additionally, they are not suitable for serving as an interceptor, which typically requires more specialized fittings designed to capture and separate waste. Thus, the T fitting's role in connecting a vent pipe is not only permitted but also practical for maintaining a properly functioning drainage system.