Understanding P&IDs Drawings

Custom Search

In continuation of our lessons on how to read and interpret P&IDs, let us look at the piping and instrumentation diagram below:

At first this P&ID looks complicated, but on closer examination, it is actually a simple P&ID. For easier understanding the P&ID is broken into:

How to Read and Interpret Piping and Instrumentation Diagrams (P&ID)

Custom Search

Let us consider some P&IDs in order to learn how to read and interpret them.

P&ID Drawing 1:

As shown in the P&ID, FT 501 is a field mounted flow transmitter connected via electrical signals (dotted lines) to a flow indicator and controller, FIC 501 located in the control room. Please note that a square root extraction of the input signal is applied as part of the functionality of FIC 501. This is because flow is proportional to the square root of the differential pressure being measured by the flow transmitter. To make flow proportional to differential pressure, the square root has to be extracted.

Basics of Piping and Instrumentation Diagrams (P&IDs)

Custom Search

P&ID stands for Piping and Instrumentation Diagram or Drawing. Alternatively, it could also be called Process and Instrumentation Diagram or simply P&I diagram or drawing. P&IDs are also known as Engineering Flow Diagrams or Mechanical Flow Diagrams .P&IDs are often used in the process industry to show the process flow and other installed equipment and instruments. They show the interconnection of process equipment and the instrumentation used to control the process.

Piping and Instrumentation Diagrams play a crucial role in the design and engineering of process plants and piping systems. P&IDs are schematic diagrams that contain engineering and design details of the process plants. It is a pictorial representation of: