- 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:
But still slowly
burning 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:
I was like, "Well, it's not gonna happen anytime soon."
And I quickly had to re-grab it.
- Dan:
That was amaze-- Like, his head's right in front of it.
Dan:
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:
Dan:
- Gav:
-
It's like a sphere
that just keeps growing out of itself.
Dan:
Pretty much just all smoke and fire.
God.
Gav:
-
- Gav:
from like a perfectly central point.
-
It's like a dragon.
Gav:
- Dan:
Oh, that's terrifying. That was the beefiest one yet.
Dan:
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. I've actually... - 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 scary.
Gav:
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.
-
It looks so nice and soft until that big flame came out.
Gav:
before 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.