1. What is Piping and Instrument Diagram?
- is a more comprehensive flow diagram which shows the interrelation among all items of equipment, piping connection and the correlation between the sensing elements and control of the instrument.
-is also called as Process Engineering Flow Diagram by other companies.
-shows typical arrangements in piping and instruments as minimum requirements considering operation, maintenance and safety.
2. Classification of P&ID
a. P&ID for Individual Unit
-This is the P&ID for the individual units composing the onsite and offsite facilities. Headers for such as utility, flare, slop and flushing oil are not generally shown in this type of P&ID and they are shown “P&ID for Utility Flow Distribution (UFD)”.
b. P&ID for Utility Flow Distribution (UFD)
-UFDs show the distribution flow for the utilities to be consumed/generated in onsite facilities, and also show the distribution for flare, slops and flushing oil.
-Hose stations are also to be stated in UFDs.
-To efficiently proceed with piping layout work, it is necessary to prepare UFDs based on actual plot plan.
-UFDs are not generally prepared for the offsite facilities, because they do not use many types of utility. The utility distribution flow for the offsite are usually shown in “P&ID for Interconnecting Pipework”.
c.P&ID for Interconnecting Pipework
-This is also called “Coordination Flow Diagram”, showing the interconnections between the units and between onsite and offsite facilities.
-To efficiently proceed with piping layout work, it is necessary to prepare this P&ID based on the overall plot plan.
d. P&ID for Tie-in Connection
-This P&ID is prepared to show the tie-in points of new units with the existing ones.
e. P&ID for Auxiliary Facilities
-There are many cases where detailed information for equipment (e.g. utility connections for pumps) cannot be shown on a “P&ID for Individual Units” due to the space limitations. In such cases, “PID for Auxiliary Facilities” is separately prepared.
f. P&ID for Packaged Unit
-This is the P&IDs for the packaged unit such as compressor, refrigeration, pure water, neutralization, etc., and normally prepared by package vendor.
-It is necessary to clearly show the scope of Company’s and vendor’s work on this P&ID and also on the related “P&ID for Individual Units” to the packaged units.
-Before the vendor starts P&ID preparation, it is necessary for Company to provide the vendor with the instructions in order to coordinate formats, symbols, configurations, etc., between the parties.
