Straight Stream Nozzle Research Paper

Choose Your Lifeline The primary way that firefighters extinguish fire is by using water to absorb the heat. When fighting a fire it is important to understand the tools brought in to a scene and how to use them. A hose line is the number one must have tool for all fire crews at a fire. There are many different kinds of nozzles used in the fire service that change the behavior of water. The two main nozzles used for fire attack are a smooth bore nozzle also known as a straight stream, and a fog nozzle also known as an aerating water stream. There has been a long standing argument in the fire service as to which nozzle is better for fire attack. A straight stream nozzle is better than a fog stream nozzle because of its ability to cool, penetrate

When using a straight stream, water comes out of the hose in a solid column with a low amount of surface area. A straight stream absorbs more heat because of its low surface area. All substances will heat up faster, the larger the surface area a substance has. Think of wood for instance, sawdust has a greater surface area than a log of wood. Sawdust will burn up much faster than a log because of the amount of surface area absorbing heat. A solid column of water will take longer to be used up and won’t convert to steam quickly. Straight streams use a large amount of gallons per minute, or GPMs. Firefighters need to understand what amount of GPMs needed to fight the BTUs. A BTU is the British thermal unit or the amount of heat that exists in the burning process of a substance. The more GPMs a firefighter has at hand, the more BTUs they can fight. A straight stream gives firefighters the best chance of cooling the atmosphere and extinguishing the fire. In contrast a fog nozzle uses an air infused water stream that has its purposes on scene, but doesn’t match the firefighting abilities of a straight stream nozzle. Air infused means nothing more than

Sometimes fire crews will position themselves away from and surrounding the burning structure which is a defensive attack called a “surround and drowned”. This technique is used when there is no safe means of entering a structure, the structure is empty, or when the structure is unsalvageable. Surround and drowned would not be possible without straight streams. Straight streams work the same way as when you were a child and placed your finger over the end of a garden hose in order to make the water shoot farther and harder. Because fire worthy of a surround and drowned are intensely hot, firefighters must be able to shoot water at great distances. A straight stream allows firefighters to do this because of the nozzle design. The water comes into the nozzle at a larger orifice and leaves the nozzle from a smaller orifice, the same as putting your finger over the garden hose. In contrast a fog stream is the same as the mist setting on a garden hose nozzle. Fog streams don’t create fog as the name would suggest, but rather, they create a wide patterned mist, shaped like a cone. Because of this nozzles behavior, shooting water up to any great distance is impossible. In reality, even if fog streams could reach a great distance, the water would get converted to steam from the radiating heat before it could reach any flame. When it comes to throwing water over a distance, a fog stream is