Methods
Mechanical fans can be used to provide positive pressure ventilation when used in tandem with either existing openings such as windows, skylights or heat/smoke vents on the roof; or by cutting new exhaust vents in the building. If there is no suitable existing hole, firefighters may use their equipment to make one, such as specialised saws for cutting a large hole in the roof. A conical hose-stream aimed around an opening -of a window or door, etc.- entrains smoke and thus increases the exhaust rate of smoke from the space. This is a process called "hydraulic ventilation". This strategy might be used when the fire is small and protecting property from smoke damage can be achieved safely. It can also be used more aggressively when a structure is "fully involved" and the smoke is obstructing the nozzlemans view of the hotspots.
High-rise buildings sometimes also incorporate fans to produce a positive pressure in stairwells and elevator shafts to reduce smoke infiltration into those spaces.
When glass windows in a burning structure burst from internal pressure and heat, or the fire burns through the roof, it may be said to have "auto-ventilated" or "self-ventilated."
Read more about this topic: Ventilation (firefighting)
Famous quotes containing the word methods:
“The ancient bitter opposition to improved methods [of production] on the ancient theory that it more than temporarily deprives men of employment ... has no place in the gospel of American progress.”
—Herbert Hoover (1874–1964)
“The comparison between Coleridge and Johnson is obvious in so far as each held sway chiefly by the power of his tongue. The difference between their methods is so marked that it is tempting, but also unnecessary, to judge one to be inferior to the other. Johnson was robust, combative, and concrete; Coleridge was the opposite. The contrast was perhaps in his mind when he said of Johnson: “his bow-wow manner must have had a good deal to do with the effect produced.””
—Virginia Woolf (1882–1941)
“A writer who writes, “I am alone” ... can be considered rather comical. It is comical for a man to recognize his solitude by addressing a reader and by using methods that prevent the individual from being alone. The word alone is just as general as the word bread. To pronounce it is to summon to oneself the presence of everything the word excludes.”
—Maurice Blanchot (b. 1907)