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 expel up to 2,000 gallons per minute. Nevertheless, as with almost all fog nozzles, those on master stream devices come with either automatic or manual spray pattern and stream adjustments. However, one significant disadvantage of fog nozzles is that Compressed Air Foam (CAF) bubbles' ratio of surface area to volume (which are formed by mixing air into a solution of water and foaming agents at the pump) exceeds that of fog nozzles' water droplets; therefore, the mechanical deflection in the nozzles themselves causes a loss of bubble structure, thereby reducing the CAF's ability to absorb heat. Despite this drawback, provided an appropriate nozzle pressure and water supply, fog nozzles are effective for any ground fire situation.
Read more about this topic: Fog Nozzle
Famous quotes containing the word roles:
“It was always the work that was the gyroscope in my life. I don’t know who could have lived with me. As an architect you’re absolutely devoured. A woman’s cast in a lot of roles and a man isn’t. I couldn’t be an architect and be a wife and mother.”
—Eleanore Kendall Pettersen (b. 1916)
“A concern with parenting...must direct attention beyond behavior. This is because parenting is not simply a set of behaviors, but participation in an interpersonal, diffuse, affective relationship. Parenting is an eminently psychological role in a way that many other roles and activities are not.”
—Nancy Chodorow (20th century)