A Process Flow Diagram - PFD - (or System Flow Diagram - SFD) shows relationships between major components in a system. A PFD also tabulate process design values for the components in different operating modes, typical minimum, normal and maximum values. A PFD does not show minor components, the piping systems, piping ratings and designations.
A Process Flow Diagram - PFD - should include:

  • process piping
  • major equipment symbols, names and identification numbers
  • control, valves and valves that affect operation of the system
  • interconnection with other systems
  • major bypass and recirculation lines
  • system ratings and operational values as minimum, normal and maximum flow, temperature and pressure
  • composition of fluids

A Process Flow Diagrams - PFD - should not include:

  • pipe classes
  • pipe line numbers
  • minor bypass lines
  • isolation and shutoff valves
  • maintenance vents and drains
  • relief and safety valves
  • code class information