Piping is a specialized engineering field concerned with the design of piping systems used to transport liquids and gases in structures and process plants, such as oil refineries. Piping drawings specify the pipe fitting types and locations and use standard symbols to represent pipes, joints, and fixtures. Piping drawings can be very complicated and hard to visualize, which makes the use of real models, such as plastic engineering models or computer models, very important. The use of CAD to build 3-D computer models has revolutionized the design and representation of process plants. This chapter is an introduction to piping components, drawings, symbols, and system modeling.