Nozzle Knowledge

Firefighters fighting residential house fire

While it shares many similarities with traditional industrial hose markets, the fire hose industry has several unique differences. One of the most significant distinctions between these markets is the added importance of the hose nozzle for the fire hoses. Generally referred to in the world of firefighting as ‘handline nozzles’ or ‘attack hose nozzles’, these pieces of equipment are essential to accurately direct and control the flow of the water as it is discharged from a hose.

By Timothy O’Neill, Marketing Manager, Kuriyama of America

Although they may seem relatively simple, fire hose nozzles are often one of the least understood tools in the firefighter’s arsenal. Typically, a fire nozzle has one primary function; to focus a pressurized stream of water directly at a fire to extinguish it. Understanding how the nozzle functions, and the different applications it is capable of, is key to ensuring that a firefighter’s equipment will perform in a reliable manner. Given the potentially dangerous situations that require the use of a fire hose, it is imperative that the nozzle be understood and function as indented.

Handline nozzles are generally used in one of two ways: to direct water into a ‘straight stream’ so that it can be used to attack the fire, or to create a water ‘shield’, a flat wall of water, to protect firefighters from flames and fumes in instances where they need to retreat from a dangerous situation.

Viper fire hose nozzle. Image courtesy of Kuriyama Fire Products

Nozzle Selection

In order to determine which nozzle is best suited for a specific situation, firefighters must know the three principle ways a nozzle’s output can vary. The first variance is the pressure of the water, measured in pounds per square inch (PSI). As the water pressure determines how far and how fast water can be sprayed from the nozzle outlet, higher amount of pressure can increase the extinguishing efficiency. The second is the pattern of the water as it exits the nozzle, and third is the discharge rate, measured in gallons per minute (GPM), which controls how quickly the water flows from the nozzle.

National Fire Protection Association (NFPA) 1964 also divides nozzles into four major types according to whether that nozzle has variable settings for pattern, pressure, or gallonage. These categories help clarify the appropriate pressure and gallonage rating for each nozzle as each type of nozzle produces a different kind of stream, and these streams have important lifesaving and firefighting properties.

Adjustable vs Constant Gallonage

Depending on the nature of the fire, firefighters often require the ability to adjust the volume of the water stream. With adjustable gallonage nozzles the hose operator is able to modify the flow rage (GPM) on the fly, while still providing constant flow rage across all patterns. This is beneficial in instances when there’s a smaller fire, and the firefighter wishes to decrease the water flow appropriate to what is required to extinguish it, saving water and reducing the chance for unnecessary water damage.

Constant gallonage nozzles maintain the same stream output (GPM) based on the firefighters preselected pressure. Whether they are spraying in a straight-stream or a fog stream pattern, these nozzles maintain a fairly constant rate of GPM. Constant gllonage nozzles therefore have one fixed discharge rate and output the maximum GPM of water when the valve is fully opened. The benefit of this design is that with fewer moving parts the nozzle allows for easier operation, which is valuable when dealing with the dangerous and unpredictable nature of a fire.

Progressive Technologies

To continually ensure the safety of firefighters and hose operators, a number of innovative techniques and technologies have recently emerged that focus on optimizing the distance of a water stream.

One of the latest industry focuses for improving fire hose nozzles is attempting to reduce the friction loss at the nozzle head. “In theory, reducing friction loss should preserve more of the initial water velocity, allowing the force that would have been lost at the nozzle head to help propel the water droplets further,” said Dan Olm, Kuriyama Fire Products (KFP) General Manager. In an effort to do so, same flow simulation software popular in the Aerospace industry are being used to measure water droplet velocity and distribution as it leaves the nozzle.

Other progressive nozzle focused technologies include improving the ease of handling and the effectiveness of a nozzle’s protection shield.

Velocity diagrams used to study water flow patterns.


Final Thoughts

Ultimately, everyone looks for different things when selecting a nozzle, which is why a broad selection is important. “You can ask two different firefighters and get three different opinions,” joked Eric Maynard, Kuriyama Fire Products National Sales Manager. “That is why we are prioritizing field demonstrations. Ultimately it is just something firefighters need to see and feel for themselves until they find that right combination of what matters most to them.”

ABOUT THE AUTHOR

Tim ONeil

Tim O’Neill is the Marketing Manager for Kuriyama of America where he helps guide development and promotion of their broad range of industrial hose and fitting; including their Kuri Tec, Tigerflex, Alfagomma and KOA Couplings and Sanitary Couplings product lines. Prior to his current role Tim served as the Tigerflex Product Specialist for seven years. Also, prior to his time at Kuriyama Tim worked in marketing for various consumer products companies.