– Hello, I’m Gav.
– I’m Dan. Welcome to “Planet Slow Mo.” You may have noticed
that A, we’re dressed
like firefighters. – All right.
Oh, that’s pretty hot!
– Let’s head outside. Gav:
This is our experiment area. Dan, why don’t you run us
through this shipping
container setup? Okay, so the fire
is gonna be all inside. Important things to know
on the outside, though, are these doors here,
which can be closed and opened. Moving along,
also there’s a window, one on each side,
that can be closed
and opened as well. And we’ve got this
Dutch door– Dutch oven– – What is it? Dutch–
– Not Dutch oven. – Just Dutch door.
– Just the door, yeah. Dutch door situation. I’ll get into that
in a minute. Let’s go inside. Inside you’ll see
our extremely nice, but extremely
flammable room. Wood all over the walls
as fuel. Very flammable couch. Dead Christmas tree.
They go up like an absolute. A backdraft is caused
when there’s a fire
in a contained area. Eventually the fire
will deplete all
the oxygen in the room and it dies down,
but it’s still sort of
burning the fuel as embers. And then what can happen
is a window might break or a door flies open,
causing a sudden rush
of oxygen into the room, which then causes
a very deadly explosion. Firefighters typically
do everything they can
to avoid a backdraft and we’re here today
deliberately causing one. Yeah, the way
we’re gonna manage that is we’ve mentioned this
fuel at the back, the Christmas tree
and the wood. We’re gonna light that. And when
that’s nicely cooking, we’re gonna shut
the back doors up, and then the fire
is gonna start to move
through the– through the room,
onto the sofa, – onto the couch, you know.
– Ahh. All that,
and it’s gonna move through, and then we’ll have
some flames coming out
the windows just here. Gonna move further
through the room. We’re gonna close
the windows up, and then the only thing
that’s gonna be open
is this front door. So we’ve got our fire.
It’s nice and hot,
about a thousand degrees. It’s come through the room, and all that’s gonna be open
is this bottom door here, allowing the oxygen in,
getting the fire nice and thoroughly
cooking the room. Then we’re gonna close this and start to
deplete it of oxygen. At that point,
we’ll then open
this top door, and then within
sort of 30 seconds of smoke pouring out
and oxygen pouring in, it’s gonna create
our backdraft explosion. To measure how far
the backdraft goes, we have these markers
placed every five feet all the way to the end. And Dan has garnished them – with a marshmallow.
– Yeah. – Make some s’mores
when we’re done maybe.
– Why not? Gav: Over there we have
the Phantom Flex 4K running at
a thousand frames a second. And inside, we have a GoPro which is in what I’m told
is a fireproof housing, – but we’ll see.
– Well, we’ll see. All right,
I think now it’s time
we hand over to the fire department
and we’ll get this
thing cooking. – All right.
– All right. It’s good. ( muttering ) All right,
what we’re looking for now is we want fire coming out
of these windows, and then we’ll start getting
fire out of the door as well. Awesome. All right, we got fire out
of this window over here. All right, close the windows. Close the front. – All right, door’s closing.
– Dan: Just the Dutch oven open. – One minute.
– Gav: So we’re currently
starving the room. Yeah, all the– all the hatches
and Dutch doors are shut. Gav:The fire
should be coming down.But still slowlyburning through fuel.Dan: So the next step is to open up that top door and let the oxygen
back in again. Man: 20 seconds. All right, they’re about
to open the door. Backdraft initiated. I wonder if there’s
much indication about when
it’s about to start. Can you tell from
the pattern of the smoke – when it’s about to go?
– I don’t know. Or does it just suddenly
just poof? Based on what I’ve read,
it’s usually quite sudden. And it’s so quiet
and there’s no visible flame that it doesn’t actually
seem that dangerous. – No.
– But, damn, would you not wanna be
stood in front of that. – I would not.
– Yeah, you would just– you would just have no idea
of the danger you’re in – if you just stood
in front of that.
– ( thud ) Dan: You can hear
the noise inside. Yeah, some temperature clunks. Sofa’s burning nicely. – Should be getting
quite close now.
– ( thud ) Oh, come on. Well, that was it. – Ooh! Whoa!
– Whoa! Flippin’… – God!
– Good Lord! – He almost went
in front of it.
– He did. All right,
let’s get a look at that. Gav:
Because he was walking in,
I let go of the pan handle.I was like, “Well, it’s not
gonna happen anytime soon.”And I quickly had
to re-grab it.– Dan:Bosh.
– Gav:Oh, my God.That was amaze–
Like, his head’s right
in front of it.Dan:Nice that he’s
wearing a mask for this.Gets some absolute
distance on that.It goes at least 40 feet.Brushed it off like it
was nothing. Like, “Yeah.” And he’s gonna go
for it again, straight up. Oh, it’s really
burning again. – Gav: It takes awhile
to get going, doesn’t it?
– Yeah. – Takes awhile to reignite.
– Gav: To reach that
critical condition. ( Gav coughs ) If a plane flies through smoke,
does it drop? Uh, if the density
of the air– – Whoa!
– Whoa! – Gav: Oh, God.
– Dan: That was intense. Look at the ferocity of this. That was a real one. Gav:So there was
very little indication.Dan:
No, there wasn’t at all.– Gav:Oh, that–
–Look at that front.–It looks amazing.
– Gav:That is mental.It’s like a spherethat just keeps
growing out of itself.Dan:It looks like there’s
something solid pushing it out.Pretty much
just all smoke and fire.God.Gav:That is insanity.–Look at that.
– Dan:Goodness me.– Gav:What an absolutely–
–I like how it growsfrom like a perfectly
central point.–Little bit of flame.
– Dan:Whoa.It’s like a dragon.Gav:I can imagine, like, a
shuttle on the other end of it.– Dan:Yeah, like a–
–Except there’s just
nothing there.Oh, that’s terrifying.
That was the beefiest one yet. Dan:Yeah, I think that’s
the effect we were after.These ones have felt
the heat a little. – Little bit of stainage.
– Yeah. – Small bit of charring.
– Oh, that one. Look at that, that one’s–
That one’s pretty– Oh, this might be
perfect, actually. Gav: The couch
and the chair gone. – The tree gone.
– Disintegrated. Oh, look at this marshmallow. – It looks good.
– It looks actually good. – Except it–
– Probably wouldn’t eat it. It fell off,
but it looks decent. Let’s have a look
around the side. – Whoa!
– It’s kind of a chilly day.
This is nice. You can really feel the heat
as you come past this window. Oh, that is really hot.
That is really hot. I bet you could fry
an egg on that. – It’s funny you say that.
– Oh, yeah. – Let’s have a go.
– …got some eggs. – Let’s have a couple.
– Yeah. – Large ones, too.
– Are you sort of
a sunny-side up… Yeah.
All right, let’s see. I think it’ll be hotter
over the back here. – Yeah, let’s try it.
– All right, here we go. – ( sizzling )
– Oh, yeah. – It’s immediately cooked.
– ( sizzling ) It’s sizzling.
It’s burnt, if anything. Just instantly cooked. Okay, Dan,
so on the show so far we’ve almost dropped a Phantom
into a hole in the Earth – from a drone.
– And we splashed it
full of water. Yeah, almost blew one away
in a wind tunnel. Why not put one in front
of a giant fireball? – Makes sense.
– Yeah. It’s in a fire-proof case. Um, but once again, you know, it’s only fireproof
until it’s not. So hopefully
it won’t get too hot. And we’ve got all the cables
coming out of the back under these blankets. So hopefully their
trigger cable won’t melt before I’ve pressed
the trigger. So you don’t fancy standing
behind the camera? – No.
– Okay, yeah. Want to keep
the old eyebrows on. All right, let’s get
a gnarly shot, shall we? Yeah. – Whoa!
– Whoa! – Dan: Looks evil coming out
of the sides there.
– It does. That’s how
you get a fire going. Dan: Look at that.
It’s just a box on fire. I don’t think
I’ve ever seen through fire into other fire
through more fire. It’s, like, there wasn’t
anything on fire. There was just
a room full of fire. All right, let’s hope
for an absolute howler. Dan: Decidedly more nervous
standing here – than I was over there.
– Yeah, it is pretty– – it’s pretty sketchy.
– Yeah. – And these are some serious
eyebrows to lose as well.
– Yeah. – It’s like a whole feature
of my face gone.
– Well, at least you’ve got – two to three people’s
worth of eyebrows.
– That’s true. They also connect
in the middle, so if maybe that bit burns off,
it’d be all right. ( both coughing ) Dan: It’s cool. You can tell
it’s sort of about to happen ’cause it starts to roll
out of the front. This is nerve-wracking. Dan: We’re on. Gav: Five, four,
three, two, one. Whoa! All right, let’s get
a look at that. Dan:A lot more ominous
from this angle.A lot more scary.Gav:Well, ’cause
it’s gonna come towards us.Instinctively,
I want to duck.Oh, look at the ball of it.It’s like a sideways geyser,in terms of what
it looks like in slow-mo.Oh, a little flame
under there.–See it?
– Dan:Yeah.It looks so nice and soft
until that big flame came out.Gav:It looks like
you can lay down in thatbefore it would
cook off your eyebrows.That’s giving me an idea
for part two. What? Well, that was some pretty
terrifying footage of a pretty terrifying event that can happen
to a firefighter. Because it’s so lethal
and dangerous, it was actually really hard
to find anywhere we can do this. Yeah, there’s not a lot
of backdraft training
facilities about. I suppose they’re
trying to avoid it – rather than create it.
– Yeah, makes sense. For that reason,
I want to say a big thanks to Travis County Fire Rescue, who managed to square
this away for us. Hopefully,
you enjoyed that video. Make sure you subscribe
to the Slow Mo Guys, and make sure
you check out part two, when we’ll create a tiny
little backdraft of our own. We should probably get out
of this building just in case they decide
to do some training in it. – You know what they’re like.
– Yeah, yeah.