ISA
ISA 5.1
Instrumentation Symbols and Identification
The symbols and tag numbering used on P&IDs. It is what makes a tag such as FIC-101 readable — the first letter the measured variable, the following letters the function.
This is an explanation, not the standard. PipingInspector is not affiliated with ISA and reproduces no part of the document. Always work to the current edition of the standard itself and to your project specification.
Where it is applied on this site
- What a transmitter is, and why it sends 4–20 mAInstrumentation & Control
- Reading a P&ID — the drawing every discipline works fromInstrumentation & Control
- Instrument installation and loop checking — where most readings go wrongInstrumentation & Control
- Reading a PFD and the material balance — where every number startsProcess