# Intrinsically Safe (IS) — Certification marks and hazardous-area classifications: cross-market equivalences

For Intrinsically Safe (IS), stated equivalent is Ex i (Ex ia, Ex ib); meaning is Limit energy below ignition threshold; governing standard / law is IEC 60079-11, verified against its source on 2026-08-11.

- **Designation:** Intrinsically Safe (IS) _(verified: appears in the quote below)_
- **Stated equivalent:** Ex i (Ex ia, Ex ib) _(verified: appears in the quote below)_
- **Meaning:** Limit energy below ignition threshold _(verified: appears in the quote below)_
- **Governing standard / law:** IEC 60079-11 _(verified: appears in the quote below)_

## What the source says

> Intrinsically Safe (IS) | Ex i (Ex ia, Ex ib) | IEC 60079-11 | Limit energy below ignition threshold

## Source

- https://exknowledge.com/pages/nec-500-vs-atex-iec.html

Last verified: 2026-08-11. Review by: 2027-08-11.
Part of [Certification marks and hazardous-area classifications: cross-market equivalences](https://referencesource.org/certification-standards-equivalence/).