3. Page 3Classification: Restricted
P&ID
What is a P&ID?
A Piping and Instrumentation Diagram - P&ID, is a schematic illustration of functional relationship
of piping, instrumentation and system equipmentcomponents.
P&ID shows all of piping including the physical sequence of branches, reducers, valves, equipment,
instrumentation and control interlocks. The P&ID are used to operate the process system.
A P&ID should include:
– Instrumentation and identification
– Mechanical equipment with names and numbers
– All valves and their identifications
– Process piping, sizes and identification
– Miscellaneous - vents, drains, special fittings, sampling lines, reducers, increasers and swagers
– Permanent start-up and flushlines
– Flow directions & Interconnectionsreferences
– Control inputs and outputs, interlocks
– Annunciation inputs
– Computer control system input
– Vendor and contractor interfaces
– Identification of components and subsystems delivered byothers
11. Page 11Classification: Restricted
PFD
• What is PFD?
• The Process Flow Diagram - PFD, a schematic illustration of theprocess
• A Process Flow Diagram - PFD - (or System Flow Diagram - SFD)shows
• the relationships between the major components in the system. PFD also tabulate
process design values for the components in different operating modes, typical
minimum, normaland maximum. A PFD does not show minor components, piping
systems, piping ratings and designations.
• A PFD should include:
– Process Piping
– Major equipment symbols, names and identificationnumbers
– Control, valves and valves that affect operation of thesystem
– Interconnection with other systems
– Major bypass and recirculation lines
– System ratings and operational values as minimum, normal and
maximumflow, temperature and pressure
– Composition of fluids
