Viking Early Suppression Fast Response (ESFR) Pendent Sprinkler VK5141 is a fast response glass bulb type sprinkler designed for use in storage areas prone to high-challenge fires. With a 28.0 (404 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.