What type of fitting can create a sealed connection between pipes without welding?

A union fitting is specifically designed to create a removable, sealed connection between two pipes without the need for welding. This makes unions particularly useful in situations where pipes may need to be disassembled for maintenance or repairs. The connection is achieved by having a threaded design, allowing the two segments of pipe to be easily connected and disconnected while still ensuring a tight seal that prevents leaks.

In contrast, adaptors, couplings, and reducers serve different functions in pipe connections. Adaptors typically connect dissimilar pipe sizes or materials but may not provide the same ease of disconnection. Couplings are generally used to join two similar pipes together, often permanently or semi-permanently, and may not accommodate easy assembly and disassembly. Reducers are used to connect pipes of different diameters, allowing for size transitions in a plumbing system, but do not inherently offer a quick-release mechanism.

The union's design and function as a secure yet easily removable component make it the ideal choice for this purpose.