Pneumatic hookup is basically Tubing/piping. 2. Process hookup. Here instruments are directly connected to process line. An example of hookup drawing is given below.

What is hookup in piping?

It means to make a connection between components in a system. Hook-up includes structural, process, mechanical, piping, electrical and instrumented control systems. Hook-up can be undertaken once the system components are positioned and installed during construction.