P & ID common symbols, How to read a P&ID.
The symbols contained in P & ID represent equipment such as actuators, sensors and controllers. Process tools such as valves (valves), instruments, and pipelines are identified by code. The codes are based on the size, type of fluid being drained, type of pipe connection (such as using Bolt or Flang), and the status of the Valve status (Normally Close or Normally Open).