Which type of fitting allows for joining pipes without soldering or welding?

The compression fitting is the correct choice because it is specifically designed to join two sections of pipe or tubing without the need for soldering or welding. This type of fitting utilizes a compression mechanism, which typically consists of a nut, ring, and body. When the nut is tightened, it compresses the ring against the pipe, creating a watertight seal. This allows for easy assembly and disassembly, making compression fittings ideal for applications where pipes may need to be disconnected and reconnected.

In contrast, socket fittings require the pipes to be inserted into a fitting socket and typically involve soldering or welding to ensure a permanent connection. Flanged connections involve bolting two flanges together, which also requires welding for a strong seal and is not categorized as a quick or removable connection. Cap fittings are used to seal the end of a pipe and do not join two pipes, making them unsuitable for the question's requirements.