Reference / Drawings / Basics

P&ID basics

A piping and instrumentation diagram shows process equipment, major piping, instruments and how they connect. Planners use it to find isolation points, instruments and relief devices before writing a package.

Draft teaching material marked until The Planner's Bench team signs off on technical accuracy. Symbols follow generally known public conventions (ISA style instrument bubbles, common mechanical and electrical one line shapes). Your site's drawing standards and procedures always govern.

Parts of a sheet

• Title block: unit, drawing number, revision and scale note.
• Drawing area: equipment outlines, piping and instrument bubbles.
• Notes and holds: design notes, material specs and open holds.

Tag numbers at GC-100

Teaching tags use area GC-100 plus a four digit loop number. Example: FIC-1001 is flow indicating controller loop 1001. Equipment uses a letter prefix: P-1001 pump, V-1101 vessel, E-1001 exchanger, PSV-1201 relief valve.

Common line meanings

Full signal and bubble shapes are on the Instrumentation legend.

Planner checklist when you open a P&ID

1. Confirm the revision matches the package.
2. Mark energy sources: process, electrical, pneumatic, hydraulic.
3. Find isolation valves, blinds and bleed points for the LOTO boundary.
4. List instruments that need calibration, proof test or bypass notes.
5. Find PSVs, rupture discs and SIS final elements that affect the outage.
6. Match tags to functional locations and equipment in SAP PM.