# Class I Division 1 — Certification marks and hazardous-area classifications: cross-market equivalences

For Class I Division 1, market / system is NEC; stated equivalent is Zone 0; meaning is Continuous hazard, recorded from its source on 2026-08-11.

- **Designation:** Class I Division 1 _(verified: appears in the quote below)_
- **Market / system:** NEC
- **Stated equivalent:** Zone 0 _(verified: appears in the quote below)_
- **Meaning:** Continuous hazard _(verified: appears in the quote below)_

## What the source says

> Continuous hazard | Class I Division 1 | Zone 0

## Sources disagree

More than one authority states this, and they do not state the same
thing. Both are reproduced with the source each came from.

### Stated equivalent

inframena.com says stated equivalent is **Zone 0**, as of 2026-08-11.

> Continuous hazard | Class I Division 1 | Zone 0

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

inframena.com says stated equivalent is **Zone 1**, as of 2026-08-11.

> Frequent hazard | Class I Division 1 | Zone 1

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


### Meaning

inframena.com says meaning is **Continuous hazard**, as of 2026-08-11.

> Continuous hazard | Class I Division 1 | Zone 0

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

inframena.com says meaning is **Frequent hazard**, as of 2026-08-11.

> Frequent hazard | Class I Division 1 | Zone 1

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


## 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/).