What is a fog nozzle?
A fog nozzle is a firefighting hose spray nozzle that breaks its stream into small droplets. By doing so, its stream achieves a greater surface area, and thus a greater rate of heat absorption, which, when compared to that of a smoothbore nozzle, speeds its transformation into the steam that smothers the fire by displacing its oxygen.
How does a pressure control nozzle work?
A highly dependable spring, connected to the baffle that forms the discharge orifice, is balanced against the water pressure in the nozzle. The pressure-control spring senses any increase or decrease in pressure within the nozzle. It then moves the baffle in or out to maintain a particular tip size necessary to keep the nozzle pressure at 100 psi.
What is the GPM setting on a conventional fog nozzle?
Conventional fog nozzles have a fixed or selectable gpm setting. These settings correspond to a particular discharge orifice, or tip size. In order for a conventional nozzle with a fixed opening to operate at the correct nozzle pressure of 100 psi, the proper gpm flow must be supplied.
How do impingement nozzles work?
Impingement nozzles allow water to exit the nozzle in a straight stream through a very small orifice (typically .008″ or about 200μ or microns) and immediately collide with a solid pin, which effectively atomizes the water into tiny droplets, usually between 1μ and 15μ.
How does an automatic fog nozzle work?
The automatic nozzle uses a principle very similar to that of a pumper relief valve. A highly dependable spring, connected to the baffle that forms the discharge orifice, is balanced against the water pressure in the nozzle. The pressure-control spring senses any increase or decrease in pressure within the nozzle.
How do you use a fog nozzle?
0:446:09Fog Nozzles - YouTubeYouTubeStart of suggested clipEnd of suggested clipOf a variable. Pattern. Both fog nozzles in use at dfr. Are designed to operate at 75 psi of nozzle.MoreOf a variable. Pattern. Both fog nozzles in use at dfr. Are designed to operate at 75 psi of nozzle. Pressure. Since this pressure is higher than a smoothbore.
What is an advantage of an automatic fog nozzle?
What is an advantage of an automatic fog nozzle? The flow rate adjusts to maintain the rated nozzle pressure.
What is the difference between a smooth bore nozzle and a fog nozzle?
Smooth bore nozzles outperform fog nozzles in that they have more operational benefits, which include: greater reach and better penetration. less nozzle reaction except for the 50-psi fog nozzle. less likelihood of being clogged by debris.
Does fog put out fire?
The fog unit proved very satisfactory, and Mr. Oroll praised it highly. fog on fire, it will undoubtedly become the leading method in combating forest fires when and where water can be used. water from 212 degrees Fahrenheit into steam requires 8,000 BTUt s.
How much psi do I need for a smooth bore nozzle?
Smooth bore nozzles generate effective streams at nozzle pressures as low 30 PSI, but the stream will degrade at pressures over 60 PSI.
What nozzle type has the highest flow rate?
Typically, the smooth-bore nozzle produces the greatest reach/gpm combination of all nozzles while at the same time using the lowest engine pump pressures.
What nozzles do firefighters use?
The Different Types of Fire Hose NozzlesSmooth-Bore Nozzles. Smooth-bore nozzles, a type of manual nozzle, have a simple, cylindrical design that doesn't consist of any internal parts to facilitate the control of gallonage or pressure. ... Constant Gallonage Spray Nozzles. ... Automatic Spray Nozzles.
Who invented the fog nozzle?
Dr. John OystonFOG NOZZLE HISTORY Fog nozzles and spray streams have been around for almost 150 years. The first United States patent for a fog nozzle was granted to Dr. John Oyston in 1863.
What is a characteristic of a fog nozzle?
Fog nozzles produce a cone-shaped stream of small water droplets. These droplets can more easily be converted into steam, which takes heat from the surrounding air and can even be used to push hot air out of a room.
What are the two types of fire nozzles?
The two main fire hose nozzle types we offer are deluge tip and smooth bore tip, but there are also economy, forestry, municipal, and Coast Guard-approved fire hose nozzles.
What is a combination fog nozzle?
A nozzle is designed to provide either a solid stream or a fixed spray pattern suitable for applying water, wet water or foam solution. Also called: Adjustable Fog Nozzle.
What is fog applicator?
AAAG Fog Applicator Nozzles are Low Velocity Fog Nozzles which are effective in combating fire in entry restricted areas in ships. These nozzle are also used to provide heat shield to the fire fighters during their operation.
What is water fog applicator?
The water fog applicator is attached to a water hose with a proper connection. It allows the fire fighter to safely fight fires from a distance. It also allows the fire fighter to fight fires that are hard to reach.
What is a combination nozzle used for?
A multipurpose nozzle is a combination smooth bore and fog nozzle. It provides the maximum reach and penetration of a smooth bore, while still enabling the benefits of a fog stream at the same time or independently.
What is a cellar nozzle?
The distributor or cellar nozzle (also called a Bresnan nozzle after one of its inventors) is designed to be used under the surface the operator is standing on. When their use is dictated, it's usually because an inaccessible location or the intensity of a below-grade fire is preventing a direct attack.
The types and distinguishing characteristics of fire hose spray nozzles
Our previous blog looked at what you need to know when purchasing or maintaining a fire hose. But it’s the nozzles at the end of each fire hose that make it possible for firefighters to safely and thoroughly extinguish a blaze. Nozzles, like hoses, need to be easy to use, durable, and right for the task at hand.
Why do we have different kinds of fire hose nozzles?
To understand what makes a nozzle better-suited to some circumstances and not others, it’s important to understand a little about fire.
Standards from the National Fire Protection Association determine stream characteristics of many fire hose spray nozzles
The National Fire Protection Association, a leading authority on fire prevention in the United States, has created guidelines for spray nozzles. These standards, written in NFPA 1964: Standard for Spray Nozzles, determine how nozzles are constructed, including how narrow or how straight streams must be.
Pressure and gallonage settings aid in the categorization of fire hose spray nozzles
NFPA 1964 divides nozzles into four major types according to whether that nozzle has variable settings for pattern, pressure, or gallonage.
Adjustable-pattern fire hose spray nozzles provide versatility, while simpler nozzles can resist clogging
Automatic, or adjustable, nozzles can adjust to increases or decreases in flow. Streams can maintain the proper shape, achieve maximum reach with the water available, and keep the correct nozzle pressure for the available gallonage.
Each jurisdiction chooses its own fire hose couplings, making a careful selection of fire hose nozzle threads critical
Each nozzle connects to a hose by threads or couplings—but not every hose has the same threads. The nozzle needs a thread connection of a compatible size and type.
Fire hose nozzle reaction and activation can significantly limit usability
As the amount and pressure of water discharge increases, nozzles become more difficult and more tiresome to control. At 50 PSI, a smooth-bore nozzle with a 15/16-inch diameter pushes against the nozzle operator with 68 pounds of force.
How much does fog nozzle pressure reduce?
Those advocating for reducing the fog nozzle pressure typically would reduce the required nozzle pressure downward from 100 psi to 75 psi. If the flow is kept constant, the reaction reduction from a 25 percent cut in nozzle pressure is 13 percent. It works out this way: a 200 gpm stream at 100 psi has 101 pounds of reaction; cutting the nozzle pressure to 75 psi reduces the reaction to 88 pounds.
What does knowing your nozzle do?
Knowing your nozzle gives you an edge over your enemy in a fire attack. (Photo/Tualatin Valley Fire and Rescue)
Why are nozzles important?
Understanding how and why nozzles work better prepares firefighters to make quick, effective knock downs. Sep 12, 2020. The nozzle on the end of a fire hose is one of the most important pieces of equipment that a firefighter has at their disposal when combating a hostile fire. It's the business end of what we do.
Why do eductor nozzles have to be fully open?
With any eductor system, the nozzle valve must be fully open to prevent excessive back pressure on the eductor, which will prevent foam concentrate pickup.
What are the advantages of using an automatic nozzle?
The advantage of using an automatic nozzle is that any flow can be delivered by the pump operator and still be controlled by the nozzle operator. Variable flow, constant nozzle pressure, and nozzleman flow control are three essential elements to successful fire streams and fire attack.
What pressure is needed to flow 150 gpm?
To flow 150 gpm in this scenario, a pump discharge pressure of 156 psi is required. The required pump pressure will vary depending on the friction loss produced, the amount of flow desired, and the length and size of the hose lay.
What does pressure control mean in a pressure nozzle?
The pressure-control spring senses any increase or decrease in pressure within the nozzle. It then moves the baffle in or out to maintain a particular tip size necessary to keep the nozzle pressure at 100 psi. In effect, the nozzle is constantly changing tip size to match the water being supplied at that moment.
Overview
A fog nozzle is a firefighting hose spray nozzle that breaks its stream into small droplets. By doing so, its stream achieves a greater surface area, and thus a greater rate of heat absorption, which, when compared to that of a smoothbore nozzle, speeds its transformation into the steam that smothers the fire by displacing its oxygen. Specially designed fog nozzles (with no stream adjustm…
Roles
Fog nozzles play an important part in firefighting tactics due to their versatility. The wide variety of fog nozzle manufacturers allows them to accommodate different sizes of fire hose—most often attack hand line—and streams and are capable in both fire protection and attack. With regard to flow rate, it is imperative to be sure that each fog nozzle be able to handle the flow rate of its water supply because the master stream devices to which they are sometimes attached can exp…
Variations
Fog nozzles come in many in different styles and sizes, but there are three types which encompass most: automatic, selectable, and manually adjustable. All contain an adjustable baffle that, like a thumb placed on the end of a garden hose, keeps their flow rates and stream reaches steady and finely adjustable despite variations in water pressure at the nozzle. To adjust the flow, the first two types use a control handle, or 'bale' located at the top of nozzle; however, selectabl…
Pattern
All styles of fog nozzles have a spray pattern adjustment. These nozzles can produce three different types of streams; the straight stream for long reach, the narrow-angle cone for advancing an attack line into a structure or fire room, and the wide-angle cone for protection and ventilation.
Images
• Automatic 1½" Fog Nozzle
• Manually Adjustable 1½" Fog Nozzle
• Manually Adjustable 2½" Fog Nozzle
• Automatic Master Stream Fog Nozzle
See also
• Impulse Fire Extinguishing System
• Spray characteristics
• Spray nozzle
External links
• Media related to Fog nozzle at Wikimedia Commons