What is a “T” fitting commonly used for in piping?

A "T" fitting is specifically designed to create a branch connection in a piping system, allowing fluid to flow in multiple directions. The design of this fitting resembles the letter "T," where the horizontal part connects to the main line and the vertical part provides access for a branch line. This configuration is essential in various plumbing and piping applications where it's necessary to divert the flow from a primary line to another pipe, facilitating efficient distribution of fluids throughout a system.

In contrast, the other choices do not accurately reflect the primary function of a "T" fitting. Joining pipes of different diameters typically requires a reducer fitting instead. Noise reduction in water flow is generally managed through other methods, such as using specific materials or installing devices like water hammer arrestors. Connecting pipes to horizontal surfaces involves different fittings and supports, depending on the system design.