P&ID Primer
P&IDs (Piping and Instrumentation Diagrams) are schematic diagrams used in process industries (refineries, chemical plants, paper mills) to map equipment, instrumentation, piping, and control systems.
The Standard Notation
Every component uses standardized symbols and letter codes. This enables scalable mapping for both human engineers and autonomous agents.
Letter Codes
| Code Position | Meaning | Examples |
|---|---|---|
| First letter | Parameter measured | F = Flow, T = Temperature, L = Level, P = Pressure |
| Second letter | Device type | T = Transmitter, V = Valve, C = Controller |
| Number | Unique identifier | 01, 02, 03... |
Example
FV01 = Flow Valve #01
This convention scales because the code itself tells you what the component does, before you read the legend.
Line Types
| Line Type | Meaning |
|---|---|
| Solid | Physical piping |
| Dotted | Signal connection |
Symbols
| Symbol | Meaning |
|---|---|
| Circle with line | Field/panel-mounted instrument |
| Circle without line | Different installation context |
Why This Matters
P&IDs work because:
- Standardization — Any engineer reads any diagram the same way
- Completeness — Every component, pipe, and control loop visible
- Scalability — Same notation works for a single unit or a refinery
- Machine-readable — Symbol codes can be parsed by systems
A&IDs apply the same discipline to AI agents + crypto instruments + smart contracts.
Questions
What makes a notation scalable from a single room to a global network?
- Does ISA-5.1 work because it encodes physical limits (pressure, temperature, flow rate) — and what are the equivalent physical limits for agent networks?
- When you translate a P&ID into an A&ID, what information is irretrievably lost in the conversion?
- At what scale does standardized notation become a bottleneck instead of an acceleration?
Next: See Symbol Library — the complete A&ID reference.