TN-25 Horizontal Spray Nozzle TN-25 Horizontal Spray Nozzle having a 25.2 (K360) K-factor is a specialized open nozzle for use in tunnel fire protection deluge systems, providing an improved alter- native to traditional designs. With its ability to provide extended coverage, the Model TN-25 Nozzle allows for a single pipe to run the length of a tunnel, compared to traditional designs that use multiple pipes in order to provide sufficient coverage.