Piping and Instrument Diagrams

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Piping and Instrument Diagrams

• CM4120
• Chemical Plant Operations

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• A PID is
• Language of Symbols
• Schematic of Process
• Displays Relative Orientation/Configuration
• Communication Tool
• Graphical Table of Contents

• A PID is not
• Piping Isometric
• Equipment Fabrication Diagram
• Scale Drawing
• Control Logic Diagram
• Something to Convey Process Information!

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Line Designator - First Letter

• W - Water or Heat Transfer
• Fluid
• L - Process Fluid
• G Gas (not a process fluid)
• V - Vent or Vacuum
• S - Steam
• C - Condensate

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Line Designator - Pipe Size

• Following line number
• is the line size
• Given in inches

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Line Designator - Pipe Spec.

• A 316 SS tubing
• w/.038 wall
• C - 316 SS pipe
• Schedule 40
• D - Carbon Steel
• Sched. 40 (steam)
• Sched. 80 (Syltherm)
• H - Copper Tubing

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Equipment Symbols
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Equipment Symbols
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Equipment Designations

• D - Distillation Tower
• E - Heat Exchanger
• F - Filter
• M - Misc. Equipment
• P - Pump
• R - Reactor
• T - Tank

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Manual Valve Symbols
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Control Valve Symbols
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Valve Failure Positions
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Instrument Symbols
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Control Symbols
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ISA Instrument Identification

• Transmitters/sensing elements
• FT flow transmitter
• LE level element
• Indicators
• AI analytical indicator
• LI level indicator
• PAH pressure alarm high
• Controllers
• TIC temp indicating controller
• FFIC ratio flow controller
• Controlled devices
• FY flow transducer
• LV level valve
• ISA The Instrumentation, Systems, and
  Automation Society

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References

• Riggs, Chemical Process Control, Appendix A
• The Engineering Tool Box,
• http//www.engineeringtoolbox.com/pid-piping-inst
  rumentation-diagram-d_466.html