Which tool is used to tighten bolts in pipe fitting applications?

In pipe fitting applications, a wrench is the appropriate tool for tightening bolts because it is specifically designed to grip and turn nut and bolt heads effectively. Wrenches come in various forms, such as adjustable wrenches and socket wrenches, allowing for flexibility in handling different sizes of bolts. By providing a secure grip and the necessary leverage, a wrench ensures that bolts are tightened to the required specifications without stripping the heads.

Other tools, while useful in their own right, do not serve the same purpose as a wrench. A screwdriver is intended for driving screws and is not equipped to handle the rounded shapes of bolt heads. Pliers, although they can grip and squeeze, lack the precision and torque application necessary for effective bolt tightening. Hammers are primarily used for driving nails or fitting pieces together but are not appropriate for tightening bolts, which require a specific rotational force. Hence, a wrench is clearly the best tool for this task.