Prefabrication Spool C&N prefabrication Pipe Spool A pipe spool is a prefabricated component of a piping system. Pipe Spools bolt up to flanges and connect, these are oftentimes used in big refineries connecting to ex-changers. Pipe Spools are made up of three components: pipes, flanges and fittings. “A Pipe Spool drawing shows a single spool and is optimized to provide all the information needed by the fabrication shop to accurately manufacture or assemble the spool.