okey, so many dont know the difference between flashover, backdraft and rollover: flashover is when suddenly everything burnabel in a room (wooden chair, table, bed, ect.) gets on fire. rollover is when the smoke gets too hot and start burning. backdraft when the fire gets to less oxygen and suddenly because of opening the door/window, the fire gets oxygen and the gases and smoke burn fast --> explosion
Tyler Huber no it is not a rollover is when the gases that are produced by the fire get trapped over head for example in the peak of a house or ceiling in a room and reach their ignition temperature and it has a rolling effect as it moves . It's quite terrifying and hot when it happens
Nice demonstration, this is definitely a backdraft. A backdraft environment has fuel and heat/fire but is starved of oxygen, watch when they open the door around 2:55 the top half of opening is venting smoke(the fuel) and the bottom is clear and watch the smoke is sucking in air/oxygen the smoke on bottom is moving inside the structure. Than the fire inside builds once more and ignites all the smoke/fuel spitting it out in a violent explosion. Smoke is fuel that's why there are also smoke explosions the difference is how and why they occur but can look similar in the end.
you can see the dense white smoke once oxygen is intro duced the natural gases inside ignite causing a backdraft it also has enough force to blow a person far away
Interesting. I can see a backdraft occurring form 2:55 to 3:30 (air being sucked in bottom quarter of window, adding oxygen to smouldering fire), then a flashover at 3:31 (the smoke itself gets so hot that it ignites all at once). Possibly the fire lost so much heat while the door was closed that it took half a minute of backdraft for the temperature to come up to flashover point.
+Benjamin Esposti : No, the "actual" back-draft (in the original sense of the term) in this video is happening 2:52 through 3:30. The explosion at 3:31 is not a "back-draft", it is a back-draft-induced FORWARD-draft, a kind of "flash-over" known as "back-draft flash-over", or sometimes just "back-draft" for short (but that usage is confusing), caused by the smoke itself bursting into flame, causing a violent outward movement of hot gasses. If you're going to call that a "draft" at all, it should be called a FORWARD-draft, as it's exactly what you expect from a fire: smoke and flames exiting a burning structure. A BACK-draft is a draft (air flow) going the opposite direction, that is, being sucked into a mostly-closed structure or container when a door or window is opened. From about 2:57 through 3:08, you can clearly see both forward-drafting and back-drafting occurring simultaneously in the open doorway. The hot gases being pushed OUT of the top 90% of the doorway are a "forward draft", which is exactly what you expect. But look at the bottom 10% of the doorway! See the cool air being sucked in? THAT is a "back-draft", and it's a tell-tale sign that oxygen is being added to a smouldering, fuel-rich, oxygen-starved fire, and that a flash-over and explosion may be imminent. And indeed, 27 seconds after back-draft starts at 2:57, we see flash-over at 3:31. To quote Wikipedia's article on "Backdraft" (look it up; [comments in brackets are mine]): "If firefighters discover a room pulling air into itself, for example through a crack, they generally evacuate immediately, because this is a strong indication that a backdraft [back-draft-induced flash-over, to be more precise] is imminent. Due to pressure differences, puffs of smoke are sometimes drawn back into the enclosed space from which they emanated, which is how the term 'backdraft' originated." And if you look carefully at the bottom 10% of the open doorway at 2:57 through 3:08 in this video, you can clearly see "a room pulling air into itself" as the Wikipedia article phrases it. A smart fireman seeing that happening in a structure fire will understand that the building is likely to explode in the next few seconds.
I thought the definitions were in dispute. Some people define backdraft the way you do; some people define is as introducing oxygen into a fuel/heat mixture to cause it to flare up.
Who cares What this is called? The key is to Quickly and Safely release the pressure and heat to the outside and get water on as much burning material as possible with a cone of water rather then a straight stream which will cover a small area thus leaving the water exposed to a heat source and create the dreaded Steam everyone cries about! If this was a house, you break out the windows at the fire room and hit the burning material with a cone of water at close range and soak everything fast. You eliminate the flames in 2-3 seconds and the room is soaked in 3-5 seconds. Stop the threat and cool the area, don't play with it!
A mi porque tengo que rendir jajajjajajjaa, y cada video que veo tiene descripciones y/o comentarios diferentes. De todos modos utilizaré la descripcion del manual para responder mi examen =)
This is actually a Great demonstration of why Vertical Ventilation Does Not Work! When he closed the door, did you see how much the pressure inside the box increased and was blasting out around the door? When you cut a hole in the roof and ignite the gasses inside the attic, the pressure in the attic increases dramatically nit decrease and that hole can not handle all the pressure. That is why you will Still see smoke escaping out every other hole in the attic/roof. When the ceiling is opened after the attic ignites, there is too much pressure in the attic to allow heat and smoke from the lower levels to escape through the hole. You have now created a cork at the top of the house and you have enabled the house to burn better. If you let the attic Suffocate and break out the windows close to or at the fire rooms, the pressure will be released directly to the outside and the radiant heat that was threatening the rest of the interior will be reduced. When you open the front door, you will not have a pressurized house to fight through. It's Very important to think for yourself and not blindly Follow what So Called Experts tell you!
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okey, so many dont know the difference between flashover, backdraft and rollover: flashover is when suddenly everything burnabel in a room (wooden chair, table, bed, ect.) gets on fire. rollover is when the smoke gets too hot and start burning. backdraft when the fire gets to less oxygen and suddenly because of opening the door/window, the fire gets oxygen and the gases and smoke burn fast --> explosion
EliJ is a rollover the same thing as a smoke explosion?
accurate:)
Tyler Huber no it is not a rollover is when the gases that are produced by the fire get trapped over head for example in the peak of a house or ceiling in a room and reach their ignition temperature and it has a rolling effect as it moves . It's quite terrifying and hot when it happens
Thank bro ! Now i know the differen betwen flashover and backdraft
when i study at school. I cannot distinguish between the two processes
Nice demonstration, this is definitely a backdraft. A backdraft environment has fuel and heat/fire but is starved of oxygen, watch when they open the door around 2:55 the top half of opening is venting smoke(the fuel) and the bottom is clear and watch the smoke is sucking in air/oxygen the smoke on bottom is moving inside the structure. Than the fire inside builds once more and ignites all the smoke/fuel spitting it out in a violent explosion.
Smoke is fuel that's why there are also smoke explosions the difference is how and why they occur but can look similar in the end.
you can see the dense white smoke once oxygen is intro duced the natural gases inside ignite causing a backdraft it also has enough force to blow a person far away
Interesting. I can see a backdraft occurring form 2:55 to 3:30 (air being sucked in bottom quarter of window, adding oxygen to smouldering fire), then a flashover at 3:31 (the smoke itself gets so hot that it ignites all at once). Possibly the fire lost so much heat while the door was closed that it took half a minute of backdraft for the temperature to come up to flashover point.
The actual backdraft happens at 3:31
+Benjamin Esposti : No, the "actual" back-draft (in the original sense of the term) in this video is happening 2:52 through 3:30. The explosion at 3:31 is not a "back-draft", it is a back-draft-induced FORWARD-draft, a kind of "flash-over" known as "back-draft flash-over", or sometimes just "back-draft" for short (but that usage is confusing), caused by the smoke itself bursting into flame, causing a violent outward movement of hot gasses. If you're going to call that a "draft" at all, it should be called a FORWARD-draft, as it's exactly what you expect from a fire: smoke and flames exiting a burning structure.
A BACK-draft is a draft (air flow) going the opposite direction, that is, being sucked into a mostly-closed structure or container when a door or window is opened.
From about 2:57 through 3:08, you can clearly see both forward-drafting and back-drafting occurring simultaneously in the open doorway. The hot gases being pushed OUT of the top 90% of the doorway are a "forward draft", which is exactly what you expect. But look at the bottom 10% of the doorway! See the cool air being sucked in? THAT is a "back-draft", and it's a tell-tale sign that oxygen is being added to a smouldering, fuel-rich, oxygen-starved fire, and that a flash-over and explosion may be imminent. And indeed, 27 seconds after back-draft starts at 2:57, we see flash-over at 3:31.
To quote Wikipedia's article on "Backdraft" (look it up; [comments in brackets are mine]):
"If firefighters discover a room pulling air into itself, for example through a crack, they generally evacuate immediately, because this is a strong indication that a backdraft [back-draft-induced flash-over, to be more precise] is imminent. Due to pressure differences, puffs of smoke are sometimes drawn back into the enclosed space from which they emanated, which is how the term 'backdraft' originated."
And if you look carefully at the bottom 10% of the open doorway at 2:57 through 3:08 in this video, you can clearly see "a room pulling air into itself" as the Wikipedia article phrases it. A smart fireman seeing that happening in a structure fire will understand that the building is likely to explode in the next few seconds.
I thought the definitions were in dispute. Some people define backdraft the way you do; some people define is as introducing oxygen into a fuel/heat mixture to cause it to flare up.
3:30
I'm assuming that had the lower door been opened, the backdraft would have occurred almost immediately?
Why? Because it could suck oxygen more efficiently?
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nice
Who cares What this is called? The key is to Quickly and Safely release the pressure and heat to the outside and get water on as much burning material as possible with a cone of water rather then a straight stream which will cover a small area thus leaving the water exposed to a heat source and create the dreaded Steam everyone cries about!
If this was a house, you break out the windows at the fire room and hit the burning material with a cone of water at close range and soak everything fast. You eliminate the flames in 2-3 seconds and the room is soaked in 3-5 seconds.
Stop the threat and cool the area, don't play with it!
A mi porque tengo que rendir jajajjajajjaa, y cada video que veo tiene descripciones y/o comentarios diferentes. De todos modos utilizaré la descripcion del manual para responder mi examen =)
This is actually a Great demonstration of why Vertical Ventilation Does Not Work! When he closed the door, did you see how much the pressure inside the box increased and was blasting out around the door? When you cut a hole in the roof and ignite the gasses inside the attic, the pressure in the attic increases dramatically nit decrease and that hole can not handle all the pressure. That is why you will Still see smoke escaping out every other hole in the attic/roof. When the ceiling is opened after the attic ignites, there is too much pressure in the attic to allow heat and smoke from the lower levels to escape through the hole. You have now created a cork at the top of the house and you have enabled the house to burn better.
If you let the attic Suffocate and break out the windows close to or at the fire rooms, the pressure will be released directly to the outside and the radiant heat that was threatening the rest of the interior will be reduced. When you open the front door, you will not have a pressurized house to fight through.
It's Very important to think for yourself and not blindly Follow what So Called Experts tell you!
This is a rollover
A roll over is not even close to this. A roll over is simply parts of the smoke/fuel igniting usually a warning before flashover.
A rollover is when all the gases in the thermal layers ignite. Hence the reason you fog spray the thermal layers and watch for ghosting.