Which of the following is NOT a method of joining pipes?

The correct answer identifies "wrenching" as not a recognized method for permanently joining pipes. In pipefitting, effective joining methods are essential for ensuring the integrity and quality of a piping system.

Welding, soldering, and gluing are all established techniques for creating strong, permanent connections between pipes. Welding involves melting the base materials together to form a solid, continuous bond, making it ideal for metals. Soldering applies a filler metal to join copper pipes, typically used in plumbing applications involving water or gas. Gluing, often used with plastic or PVC pipes, utilizes adhesives to bond the surfaces together tightly.

In contrast, "wrenching" refers to a method of mechanically tightening pipes and fittings, typically with a wrench, but does not inherently create a permanent joint. It may be part of the process to ensure a connection is secure, especially in threaded or flange fittings, but on its own, it does not effectively join pipes in the same way as the other methods listed.