What is the minimum nozzle pressure for fog-stream nozzles according to standard engine pressure requirements?

The minimum nozzle pressure for fog-stream nozzles being 85 psi is established to ensure effective water delivery and adequate reach of the stream. This pressure allows the nozzle to create a fine mist or fog that enhances cooling and wetting capabilities, which is critical for fire suppression. At this pressure, the nozzle can produce the desired spray pattern necessary for maximizing surface area contact with the heat, supporting a more efficient extinguishing process.

The choice of 85 psi is typically recognized in fire service standards, balancing the need for effective water delivery without compromising the safety of firefighters or equipment. This pressure helps maintain a stable and controllable stream, enabling firefighters to maintain effective operations in fire suppression scenarios.

Setting the nozzle pressure too low could lead to an insufficient mist formation or reduced reach, making it ineffective against certain fire conditions. Conversely, excessively high pressures can strain equipment and make the stream difficult to handle. Therefore, the establishment of 85 psi represents a standard that promotes both efficiency in firefighting tactics and safety for personnel.