# UL 228 — Which OSHA NRTL is recognized for which test standard: all 21 labs' scopes of recognition, cross-referenced

For UL 228, laboratory is CSA Group Testing and Certification Inc; standard title is Door Closers-Holders, and Integral Smoke Detectors, verified against its source on 2026-08-10.

- **Laboratory:** CSA Group Testing and Certification Inc. _(verified: appears in the quote below)_
- **Standard number:** UL 228 _(verified: appears in the quote below)_
- **Standard title:** Door Closers-Holders, and Integral Smoke Detectors _(verified: appears in the quote below)_

## What the source says

> UL 228 | Door Closers-Holders, and Integral Smoke Detectors |

## Source

- https://www.osha.gov/nationally-recognized-testing-laboratory-program/csa

Last verified: 2026-08-10. Review by: 2026-12-08.
Part of [Which OSHA NRTL is recognized for which test standard: all 21 labs' scopes of recognition, cross-referenced](https://referencesource.org/nrtl-recognition-scopes/).