UL 1821 — Thermoplastic Sprinkler Pipe and Fittings for Fire Protection
Reference: UL 1821 · Scheme: OSHA NRTL product safety. The 2 laboratories below appear in the Current list of Nationally Recognized Testing Laboratories for this standard. Retrieved July 2026; ranking criteria on the methodology page.
| # | Laboratory | Location | Cert / ID | Approved | Registry accreditations |
|---|---|---|---|---|---|
| 1 | UL LLC | Northbrook, Illinois, United States | — | — | 6 |
| 2 | NSF International | Ann Arbor, Michigan, United States | — | — | 1 |
Facts reproduced from the linked registry as retrieved July 2026. No ratings, no reviews — see methodology.