P&ID Symbols and Codes Process equipment such as valves, instruments, and pipelines are identified by codes and symbols. As well as devices and pipelines a P&ID will commonly contain, information on vents drains, and sampling lines as well as flow directions, control IO, and interconnection references. Watch the video and answer the question. What are 3 pieces of equipment represented by P&ID symbols? Tag someone who needs to see this! #P_IDcodes #P_IDsymbolsl #Engineering #Technology #Industr