Sprinkler, Quick-Response (QR) : A type of spray sprinkler that meets the fast response criteria of 3. 6. 1(a)(1) of NFPA 13 and is listed as a quick-response sprinkler for its intended use
NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2008 ed. https://law.resource.org/pub/us/cfr/ibr/004/nfpa.2 5.2002.pdf, (Std: Insp, Testing, and Maint of Wtr-Based Fr Prac Sys - Amer) {191 NFC}