- Fog nozzle
A fog nozzle is a
firefighting hosenozzle that breaks the water that flows through it into tiny droplets of water. The theory is that small droplets of water create moresurface area than a solid stream created by a smooth bore nozzle. The water absorbs the heat, turns into steam, and displaces theoxygen ,smothering thefire . With the increase of surface area, this job is done quicker. Specially designed fog nozzles (with no stream adjustment) have been certified byUnderwriters Laboratories (UL) for use on Class B & C hazards.Roles
Fog nozzles play an important part in firefighting tactics. These types of nozzles are very versatile and can accommodate different sizes of fire hose and fire streams. They can be used for protection and for fire attack. When given the appropriate nozzle pressure and
water supply , they are effective for any fire ground situation.Fog nozzles are typically used with fire attack hand lines. Most hand lines are 1 1/2”, 1 3/4”, and 2 1/2” diameter fire hose. The fog nozzle that will be used on each size of fire hose is made to handle the maximum gallons per minute (GPM) rating that the fire hose can handle. There are fog nozzles that are used with
master stream appliances also. A master stream can flow between 350gpm to 2000gpm. The fog nozzles placed on these types of appliances are made to handle that high of flow rate. Even with that high of flow rate, these fog nozzles are still made with spray pattern adjustments and in the automatic or manually adjustable styles.Variations
Fog nozzles are made in different styles and sizes. The two styles to choose from are the automatic fog nozzles and the manually adjustable fog nozzles. Both of these nozzles can be adjusted for the gallons per minute a firefighter needs to do the job. The automatic fog nozzle relies on a constant pressure at the nozzle. The firefighter can operate the open-close handle, and the nozzle will adjust the rate of flow by itself. This will give the firefighter the best flow rate with the given amount of water. The manually adjustable fog nozzle works differently. On these types of nozzles there is a flow adjustment around the tip of nozzle. Usually the 60gpm (gallons per minute), 95gpm, and the 125gpm flow rate selection settings are on the bezel; depending on the size of the nozzle. The
firefighter can select one of these settings before or after the nozzle is opened. Once one of these gallon settings has been selected and supplied with the appropriate pressure, the flow rate will remain consistent with the gallons per minute selected.Pattern
All styles of fog nozzles have a spray pattern adjustment. These nozzles can produce three different types of streams; the straight stream, the narrow-angle cone, and the wide-angle cone. Each of these types of streams is used for different purposes. The straight stream can be used for long reach. The narrow-angle cone can be used for advancing an attack line into a structure or the fire room. Protection and ventilation is the typical use of the wide-angle fog pattern. These types of spray patterns assist the firefighter in accomplishing his or her fire suppression efforts.
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Impulse Fire Extinguishing System ources
*cite book|title=Fundamentals of Fire Fighting Skills|location=Sunbury|publisher=Jones and Bartlett Publishers, Inc.|year=2004
*cite book|author=Hall, Richard, and Barbara Adams|title=Essentials of Fire Fighting. 6th ed. |location=Stillwater|publisher=Fire Protection Publications, Oklahoma State University|year=1998
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