# T6 — Certification marks and hazardous-area classifications: cross-market equivalences

For T6, market / system is IEC / ATEX; applies to is 85°C, verified against its source on 2026-08-11.

- **Designation:** T6 _(verified: appears in the quote below)_
- **Market / system:** IEC / ATEX _(verified: appears in the quote below)_
- **Applies to:** 85°C _(verified: appears in the quote below)_

## What the source says

> IEC / ATEX System | Continuous hazard | Class I Division 1 | Zone 0 | Frequent hazard | Class I Division 1 | Zone 1 | Occasional hazard | Class I Division 2 | Zone 2 | Zone systems offer more precise classification of hazard frequency , while the Class/Division system is simpler and historically used in North America. Gas Group Equivalency NEC Group | IEC Group | A (Acetylene) | IIC | B (Hydrogen) | IIC | C (Ethylene) | IIB | D (Propane) | IIA | Temperature Classes Electrical equipment must also be rated according to maximum surface temperature to prevent ignition. Temperature Class | Max Surface Temp | T1 | 450°C | T2 | 300°C | T3 | 200°C | T4 | 135°C | T5 | 100°C | T6 | 85°C |

## Source

- https://www.inframena.com/hazardous-area-classification-equivalency-guide/

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/).