# UL 1638 — Which OSHA NRTL is recognized for which test standard: all 21 labs' scopes of recognition, cross-referenced

For UL 1638, laboratory is Intertek Testing Services NA, Inc; standard title is Visual Signaling Appliances, verified against its source on 2026-08-10.

- **Laboratory:** Intertek Testing Services NA, Inc. _(verified: appears in the quote below)_
- **Standard number:** UL 1638 _(verified: appears in the quote below)_
- **Standard title:** Visual Signaling Appliances _(verified: appears in the quote below)_

## What the source says

> UL 1638 | Visual Signaling Appliances |

## Source

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

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/).