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P&ID vs process flow diagram
3

P&ID vs process flow diagram

P&ID vs process flow diagram

(OP)
What is the difference between the two?  Is one more detailed than the other?

RE: P&ID vs process flow diagram

In our plant, the process flow diagram is only as detailed as necessary to define individual process streams. For example, for a pair of pumps, only one is shown.  For a bank of exchangers, only one is shown.  For a control valve station, the bypass is not shown.  Flanges, bleeds, drains and not shown.  The P&ID, on the other hand has all piping and instrumentation components shown.  It should include every flange, every valve, every instrument, every reducer every exchanger and every pump.  It should include all piping connections down to the drains and bleeds.

Johnny Pellin

RE: P&ID vs process flow diagram

2
In Cowboy terms, a "PFD" (Process Flow Diagram) is a schematic representation of what the "stuff" is, where it's going and what's controlling getting it there.  A "P&ID" (Piping & Instrument Diagram) expands on the PFD and describes (actually, it largely specifies size, materials, components, equipment and devices) the conveying and controlling apparatus and conduit through which the "stuff" flows.  In other words, the PFD accurately describes the "stuff" on the inside, whereas the P&ID accurately describes the things on the outside through which this "stuff" is routed.  The PFD is a schematic representation of the flowing matter; the P&ID is a schematic representation of the mechanical apparatus.

Sorry if I sound like a wingnut.

Regards,

SNORGY.

RE: P&ID vs process flow diagram

The P&ID diagrams shows all component and their sizes for the project ( main and auxiliary equipment) .
The PFD shows all descripcions related with the process. (e.g. pressure, flows, temperatures, drop pressure, power, current, etc.)

RE: P&ID vs process flow diagram

Quote (SNORGY):

The PFD is a schematic representation of the flowing matter; the P&ID is a schematic representation of the mechanical apparatus.

I don't think I have ever seen it put that way, but in my opinion this is the best and most concise description of the difference that I have seen.

Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com

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