The Viking XT1 VK4621 is the direct replacement to the now-obsolete Viking VK462.
Viking VK4621 Standard/Quick Response XT1 Concealed Pendent Fire Sprinkler delivers decorative, competitively priced defense against fire in up to ordinary hazard, group II applications (cULus). Using a heat-activated 3mm glass bulb, this automatic fire sprinkler opens when ambient temperatures reach 155F (68C), reducing the likelihood of flashover and facilitating safe evacuation. It is UL-listed for quick response applications with a maximum pressure of 250 PSI and FM approved for standard response applications with a maximum pressure of 175 PSI.
The Viking Model XT1 has a 5.6 K-Factor and installs with 1/2 in. (12.7 mm) National Pipe Thread (NPT), used in fire sprinkler systems throughout the United States. This Quick Response Fire Sprinkler features a brass body, copper deflector, and nickel-alloy sealing assembly coated with PTFE tape. The sprinkler's threaded adapter cup is designed to be installed with a low-profile cover plate that provides up to a 1/2 in. of adjustment.
This pendent sprinkler hangs from above-ceiling piping and may be installed and used in accordance with NFPA 13 and local fire code. Each Model XT1 concealed sprinkler is made by Viking, a global leader in fire protection manufacturing for nearly 100 years.
This product is UL listed and FM approved, and appropriate for use in fire protection systems when accepted by the authority having jurisdiction. In accordance with NFPA 13, a higher temperature rating may be required when installing a fire sprinkler in or near heat sources, unventilated spaces, uncovered steam mains, or uninsulated rooftops. Concealed pendent sprinklers should not be installed where the air pressure above the ceiling is greater than the pressure below, which may prevent or delay sprinkler activation in the event of a fire.