# ISA ANSI/ISA-5.1-2024

Standards · `ANSI/ISA-5.1-2024` · verification: source checked

ANSI/ISA-5.1-2024, Instrumentation and Control – Symbols and Identification, is a standard that defines a uniform system for depicting and identifying instruments, devices and their functions in instrumentation and control systems. It sets out consistent symbols and identification methods used in the design, installation, operation and maintenance documentation of such systems. The standard was first published in 1949; the 2024 edition updates the title to include symbols for control and adds new symbols, new reference sections and a loop instrument diagram symbol table.

## Specification

| Property | Value |
|---|---|
| Body | ISA |
| Reference | ANSI/ISA-5.1 |
| Edition year | 2024 |
| Status | published |

## Study notes

- First published in 1949.
- The 2024 edition changed the title to Instrumentation and Control – Symbols and Identification to emphasize that symbols for control are included, and improved readability.
- The 2024 edition added new symbols, recognized new automation technology, added new reference sections and added a loop instrument diagram symbol table.
- Maintained by the ISA5 standards committee, which oversees working groups producing standards, recommended practices and technical reports for documenting measurement and control instruments and systems.
- ISA-TR5.1.02-2024 (Identification System Guidelines), ISA-TR5.1.03-2024 (Graphic Symbol Guidelines) and ISA-TR5.1.04-2026 (Content for PFDs and P&IDs) are technical reports that supplement ISA-5.1.
- ISA-5.4-1991 on instrument loop diagrams emphasizes consistency in format and the use of standardized symbols as found in ISA-5.1.

## Sources

1. [ISA-5 Series of Standards](https://www.isa.org/standards-and-publications/isa-standards/isa-5-standard) (accessed 2026-10-25)

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