Guide to P&IDs - Purpose, Drawing Format, Symbols and Abbreviations

Oct 28, 2026

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Guide to P&IDs outlines the purpose and role of P&IDs as process and instrumentation drawings and as a basis document for designing process facilities. It explains how P&IDs link to a common database, including automatic population during development, and how specialized reports like instrument indexes or PLC I/O lists can be generated. The guide also details P&ID drawing format, including structural levels and specific bands, and summarizes key symbols and abbreviation conventions for instrumentation, power devices, and PLC-related I/O.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

I. Purpose of P&IDs

P&IDs are

P&IDs and databases

P&IDs show

II. P&ID Drawing Format

General

Field Band

Power Source Band

PLC I/O Band

III. P&ID Symbols and Abbreviations

General

Instrument Bubbles

GUIDE TO P&IDs I. PURPOSE OF P&IDs A. P&IDs are: 1. Process and Instrumentation Drawings. 2. The basis document for the design of all processes and facilities. a) If it is NOT on the P&IDs then it is NOT part of the facilities process system. 3. A single document that coordinates and incorporates the design items needed to carry over to the final design by the individual disciplines. B. P&IDs and databases: 1. P&IDs are linked to a common database. 2. The database is populated at the same time the P&IDs are developed. 3. Mechanical, Electrical, Instrumentation, and Process information resides within this document system. 4. Specialized reports can be generated from the database such as an instrument index or PLC I/O list. C. P&IDs show: 1. All valves, whether manual or controlled, independent of size. 2. Line sizes, designations, and materials. 3. Equipment characteristics such as pump type, flow rate, head, horsepower, voltage, etc. 4. Electrical characteristics such as power source, starting mechanism, variable frequency drive, vendor control panels, etc. 5. Instrumentation characteristics such as: a) Range. b) Scale. c) Material compatibility. d) Block and bleed valves. e) Analyzer requirements. f) Power source. g) Fieldbus. h) Hardwired needs. i) PLC/IO requirements. GUIDE TO P&IDs II. P&ID DRAWING FORMAT A. General: 1. The structural level format groups the individual P&ID symbols in horizontal bands, which represent separate physical areas, within the document. GUIDE TO P&IDs B. Field Band: 1. Reflects the process flow from left to right. 2. Depicted in the band: a) All components that are physically located in the field (piping, valves, equipment, instruments, etc. ) . b) Equipment furnished with a vendor control panel. c) The function of this band is to show the process flow. C. Power Source Band: 1. This band reflects the power source for all powered devices in the field. 2. Power sources identified in this band and their associated control include: a) MCCs. b) VFDs. c) Panelboards. d) Circuit breakers. e) Fuses. f) Any other power devices located in an electrical room or control panel. GUIDE TO P&IDs D. PLC I/O Band: 1. Contains the PLC I/O devices as well as some logic used to describe the control functions. 2. The symbol set and designations identify hardwired I/O such as: a) Discrete inputs (DI) . b) Discrete outputs (DO) . c) Analog inputs (AI) . d) Analog outputs (AO) . e) Register connections for field bus connected devices. GUIDE TO P&IDs III. P&ID Symbols and Abbreviations A. General: 1. P&ID Symbols and Abbreviations can be found on general drawings 00GN01 to 00GN04 . 2. Supplemental equipment tagging instructions are found on general drawings 00GN07 and 00GN08 . B. Instrument Bubbles: 1. PLC Hardwire I/O Point. 2. PLC I/O Register (Fieldbus I/O) . GUIDE TO P&IDs 3. PLC Based Human Machine Interface (HMI) . 4. Pilot Device Operator Interface. GUIDE TO P&IDs 5. Power Device Primary Function: Operator Accessible. 6. Power Device Auxiliary Function: Operator Accessible. 7. Power Device Primary Function: Operator Inaccessible. GUIDE TO P&IDs 8. Power Device Auxiliary Function: Operator Inaccessible . 9. Instrument Primary Element. 10. Instrument/Control Element Primary Function: Operator Accessible. GUIDE TO P&IDs 11. Instrument/Control Element Auxiliary Function: Operator Accessible . 12. Instrument/Control Element Primary Function: Operator Inaccessible. 13. Instrument/Control Element Auxiliary Function: Operator Inaccessible. GUIDE TO P&IDs 14. Field Equipment: Non-Powered. 15. Field Equipment Primary Function: Powered. 16. Field Equipment Auxiliary Function: Powered.

FAQs

What is the purpose of P&IDs in facility design?

P&IDs are process and instrumentation drawings and act as the basis document for designing all processes and facilities. They also coordinate and incorporate design items needed for final design across disciplines.

How do P&IDs relate to the database and reporting?

P&IDs are linked to a common database that is populated as the P&IDs are developed. Mechanical, electrical, instrumentation, and process information resides in this system, enabling reports such as an instrument index or PLC I/O list.

What drawing bands and information are included in the P&ID format?

The format uses structural level bands, including a Field Band for process flow and physically located components, a Power Source Band for power for all powered field devices, and a PLC I/O Band containing PLC I/O devices and logic describing control functions.

Oct 28, 2026

Upload by Himbo