When it comes to fire fighting spray nozzle, there are many options. Each has its own purpose, and using the right tool for the job is necessary for a quick, effective, and safe solution to a fire. Just like trying to insert a screw with a hammer or cutting steak with a saw, the wrong nozzle for a fire suppression task can lead to disastrous results.
Nozzle selection is based on each fire department’s standard operating procedures and policies, as well as the mission of each truck in the fleet. For example, an initial attack pumper will typically be equipped with straight stream nozzles for immediate water application to support fireground operations, while a ladder truck will include fog nozzles to allow firefighters to use the water curtain they create to evacuate occupants from a building and provide exposure protection.
The type of fire suppression material that’s discharged from a hose nozzle also depends on the kind of fire that is occurring. There are five different classes of fires, and each requires a specific firefighting agent to be extinguished. For Class A fires, for example, which involve combustible materials such as fabric, paper, and wood, it’s critical to quickly and efficiently extinguish the flames by depriving them of oxygen. A straight stream nozzle is best suited for this, as it discharges a narrow column of water droplets with superior reach and penetration capabilities.
Other fires, such as Class B fires which involve combustible liquids such as gasoline or paint, require a foam-based extinguishing agent that’s much more dense than water. Fog nozzles, which discharge a fine mist of small water droplets that can more easily be converted into steam, are better suited to these kinds of scenarios.
Another important consideration is whether or not a firefighting spray nozzle can be adjusted to change from straight stream to fog mode and back again as the needs of each call scenario changes. A constant gallonage nozzle is designed to maintain the same orifice size when changing patterns, while an automatic nozzle can adjust as the pattern changes.
The types of fire suppression nozzles firefighters choose to deploy at the scene may also be influenced by regulations, such as NFPA 1964: Standards for Spray Nozzles, which dictate how wide or narrow a water stream must be. Firefighters can also select a fire fighting nozzle with an adjustable flow rate to increase or decrease the amount of water that’s being delivered.
Firefighting nozzles are connected to a fire hydrant through threaded connections. Not all hoses have the same threads, so it’s important that each nozzle has a compatible connection size to ensure maximum safety and efficiency. Some nozzles feature a quick connect system, while others require special adapters that make them easy to install or remove from the hydrant.