1. Component And Instrument Symbols
Module 5
To read and interpret piping and instrument drawings (P&IDs), the reader must learn the meaning of the symbols. When the symbology is mastered, the reader will be able to interpret most P&IDs.
The reader should note that this module is only representative of common symbology, rather than being all-inclusive. The symbols presented herein are those most commonly used in engineering P&IDs. The reader may expand his or her knowledge by obtaining and studying the appropriate drafting standards used at his or her facility.

2. Learning Objectives
Given component and instrument symbols, identify them with 90% accuracy
Given component and instrument symbols, identify component symbols with 90% accuracy
Given component and instrument symbols, identify instrument symbols with 90% accuracy
Given component and instrument symbols, identify them with 90% accuracy
Given component and instrument symbols, identify component symbols with 90% accuracy
Given component and instrument symbols, identify instrument symbols with 90% accuracy

3. Without a knowledge of the symbology used a drawing can look as if it was created in a foreign language and un recognizable. Just take a look at this drawing. Can you make out any of the symbols? We will briefly discuss some of the symbols found on this drawing and other common symbols. To become an expert in P&ID symbology is above the level of this course.
We will be looking at three different groups of Component Symbols and one group of Instrument Symbols, so lets take a look at our first group of Component Symbols, Valve Symbols.

4. Valve Symbols
Valves are used to control the direction, flow rate, and pressure of fluids.
[left column]
Gate or Generic Valve
Hand Controlled Valve
3-Way Mixing Gate Valve
Generic Control Valve
[Right column]
Butterfly Valve
Slide Gate Valve
Triple Duty Valve
It should be noted that globe and gate valves will often be depicted by the same valve symbol. In such cases, information concerning the valve type may be conveyed by the component identification number or by the notes and legend section of the drawing; however, in many instances even that may not hold true.

5. Pump Symbols
Pumps are drawn showing the direction of flow represented by an arrow.
[Left Column]
Vacuum Pump
Air Driven Diaphragm Pump
Centrifugal Pump
Rotary Pump
[Right Column]
Sump Pump
Submersible Pump
Motor Driven Diaphragm Pump
Gear Pump

6. Instrument Symbols
One of the main purposes of a P&ID is to provide functional information about how instrumentation in a system or piece of equipment interfaces with the system or piece of equipment. Because of this, a large amount of the symbology appearing on P&IDs depicts instrumentation and instrument loops.
Here are just some of the common intrument symbols you will see on a P&ID
[Left Column]
Pressure Switch Except Where Noted otherwise
Locally Mounted Instrument
Local panel Mounted Instrument
Instrument with two functions
Hydraulic Motor Bi-Directional
[Right Column]
Panel Mounted Patchboard or Matrix
Purge or Flushing
Reset for Latch Type Actuator Behind Local Panel
Variable speed motor
Motor driven centrifugal Pump

7. Review
Symbology is a large part of a P&ID drawing that requires mastering
Common types of Component Symbols are Valves and Pumps
Instrument Symbols provide functional information about how it interacts with a system
Review
Symbology is a large part of a P&ID drawing that requires mastering
Common types of Component Symbols are Valves and Pumps
Instrument Symbols provide functional information about how it interacts with a system

8. Flash Cards
To help you become more familiar with the symbols shown in this module use the Flash Cards to study.