Viking's Early Suppression Fast Response (ESFR) Dry Pendent Sprinkler VK504 is a fast response fusible element type sprinkler designed for use in storage areas subject to freezing and supplied from a wet system only, in an adjacent heated area. With a 16.8 (242 metric*) nominal K-Factor and special deflector, this sprinkler produces large, high-momentum water droplets in a hemispheric pattern below the deflector. This permits penetration of the fire plume and direct wetting of the burning fuel surface while cooling the atmosphere early in the development of a high-challenge fire.  Sprinkler VK504 may be used in the protection of most common storage materials, including encapsulated or unencapsulated Class I, II, III, and IV commodities, and Group A Plastics. The VK504 successfully meets new UL 1767 test standard and compliance program for ESFR sprinklers installed in rack storage with high clearances to ceiling (20 ft or greater).  ESFR Dry sprinklers can ONLY be installed in Wet systems! Not for installation in dry or preaction systems.