Why do firemen cut a hole in the roof?

Dangerous superheated gases and dark smoke accumulate in a burning building. Heat and smoke rise into the attic where the fire can move quickly. Firefighters may go ahead of the fire on a roof and cut holes to access the attic to stop the fire from spreading through the attic.

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What happens if you open a door during a fire?

Fires need oxygen to sustain itself and opening the door provides oxygen flow [which] exposes people to dangerous heat levels and toxic carbon-monoxide gas," Steve Kerber, director of the UL Firefighter Safety Research Institute, told INSIDER. Keeping this in consideration, should you open windows in a fire? Breaking open windows allows the fire to gain more access to oxygen which helps the fire grow, which would greatly decrease your chances of escape. By keeping the windows closed you are starving the fire as much as possible.

Which 4 things should you not do in the event of fire?

10 things not to do in a fire Don't install smoke alarm detectors. Pop upstairs to retrieve heirlooms, passports and pets. Open doors that have smoke billowing from the joints. Throw water on a chip pan fire. Try and escape using a Lift. Jump from an upstairs window. Hide in a cupboard or under the bed. Smoke cigarettes in bed. Correspondingly, can a wet blanket catch fire? Firstly the wet blanket will not burn as easy, so there is a better chance of it not burning through. Even more importantly is that the wet blanket will produce steam, some will escape to the outside, but much of it will stay below the blanket and help extinguish the fire.

Moreover, on what part of a swimmer's body does the water's reaction force push?

For a swimmer moving his arms through water the greatest lift and drag forces are exerted on the part of the arm that moves fastest through the water, which are generally the hand and forearm. The forearm also generates significant propulsive force in the form of drag.