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View Full Version : Vehicle collision and subsequent explosion - how hot would it feel to nearby onlookers?



Los Pollos Hermanos
04-04-2015, 05:31 AM
Pretty please - a quick ask for clarification for my Big Edit:

Two (speeding) vehicles - a station wagon and a delivery truck - collide at a suburban intersection and burst into flames within seconds. The collision is witnessed by three police officers, who are stood at an unspecified safe (i.e. won't get burnt) distance from the intersection.

I don't want/need to go into lots of detail, but I want the reader to imagine the officers are close enough to the explosion to feel the heat produced, but with no lasting damage. Would it be like a wave of heat travelling over the area? Would it produce any short-lived physical effects like drying their eyes/mouth/throat? Am I completely wrong and need to re-think the scene?!

Muchos thanks in advance,

LPH.

shakeysix
04-04-2015, 06:38 AM
I was once involved in a pile up on an inter state in Houston. I was visiting my sister who lived in Spring at the time. We were returning from our aunt's birthday party so i know the day was January 29th. Not so sure about the year, 1995 would be close enough. It was close to ten p.m. and cold. Not as cold as Kansas but I was wearing a sweater and a jacket. We were stopped, all traffic on both sides of the interstate, because there was a bad accident about a half mile ahead. While we were stopped a stretch limo slammed into the stopped traffic, it pushed a car behind us into a car next to us. All three cars burst into flames. My brother-in-law, who is a jerk but one hell of a brave jerk, kicked out a car window and pulled a young woman out of a burning car. He and my brother went to help other people. Other people were also helping--a lot of people had kids and everyone was trying to comfort the kids and keep them warm. Our car wasn't hurt but my sister and I went to the side of the highway with several other people. Eventually we returned to our car. I was holding my 5-6 year old niece in my arms. It was cold except where the fire reflected on us. I don't remember a lot of details. I'm from a town so small we don't have a single traffic light. The sirens, fire trucks, ambulances are mainly what I remember but the tires exploded and hub caps were flying in the air. I remember the hubcaps more than the heat from the fire. --s6

One funny thing: the girl my brother-in-law rescued was a Vietnamese teenager. There was a doctor in one of the cars who came to treat her and there was a Vietnamese man trying to translate for her but the girl kept yelling "I speak English! I'm an American!" over and over. My bil, had been trained in the Navy, thought she would be okay. I hope so. --s6

Los Pollos Hermanos
04-04-2015, 02:50 PM
Many thanks for the info, and I hope you're now ok after being involved in such a horrific incident - sounds like everyone had a lucky escape. Very brave of your BiL to get that girl out - I also hope she made a full recovery.

Incidentally, I've roadtripped in seventeen states (I don't count an earlier long weekend in NYC as roadtrippin'!) and I have to say Houston has got to be the nastiest place I've ever driven. So many aggressive people driving on your arse on and off the freeways (Dallas wasn't much better) and doing things that would get your throat punched out in the UK. People go on about Los Angeles drivers but, apart from them being a bit loopy on the freeways, I found LA infinitely more civilised than Houston and Dallas. I've also been through Kansas - drove from Colorado Springs to Dodge City, and then down to Oklahoma City. I loved the feeling of openness you get on the plains - nothing like our overcrowded little island!

Now you've made me want another road trip!!!

I'd never have thought of exploding tyres and flying hubcaps - I suppose with the intense heat the air inside the tyres would have expanded, causing them to explode.

When you were stood by the side of the road, how hot did the heat from the fire feel? My story's collision takes place during a hot summer, so whilst the air temperature would be around 40oC / 104oF the onlookers would be wearing summer clothes, therefore more of their skin would be exposed to any heat reaching them from the burning vehicles.

So many variables...

Thanks again,

LPH. x

Chris P
04-04-2015, 03:03 PM
I don't have a direct answer to your question, but I knew a firefighter who said cars don't explode like they do in the movies, they just burn and burn and burn. He said when the tires pop, however, your heart jumps about four feet out of you, like Shakey described. I don't remember the technical term, but there is a measure of how fast a flame will travel along a trail of fuel. Gasoline is very fast, diesel fuel slower, kerosene (aka paraffin) slower, and thicker oils even slower. That's why fire breathers use kerosene and not gasoline! The relevance of that is the *foof!* of gasoline ignition gives a feeling of an explosion, even if it technically isn't one.

You might look up the temperatures of a gasoline and plastic fires (plastic fires aren't very hot, surprisingly) and compare that to any wood fires you might have been near to get an idea. Of course it will depend on how much material is burning, but it might give you an idea.

shakeysix
04-04-2015, 03:37 PM
It was a cold night for Houston, probably well above freezing though. I remember trying to keep the kids warm until we could get back into our cars. Not much about the heat except when I turned my niece away from it--she didn't want to see the flames, I could feel warmth on my back. But you know what a bitch memory is, that could be false because i am trying to remember a specific detail. The smells were burning rubber and gas, chemically stuff.

Because the night was cold, the heat didn't register. I think the heat would have been a lot more uncomfortable in summer.

Chris is right, the cars didn't explode but the tires did. There were a lot of metallic sounds and breaking glass, sirens and people screaming, a firetruck almost hit us--the sounds are what I remember. When the long limo hit the stopped cars it didn't brake, just slammed right into them. That sound was awful--like running a car down a garbage disposal. --s6

jclarkdawe
04-04-2015, 06:09 PM
It's unusual for cars to catch on fire after an accident. It is even rarer for them to actually explode.

You're not going to stand close enough to a car likely to explode where you can feel the heat blast. You stay low and the heat tends to go over your head. Cops never get that close to a burning car unless they're trying to rescue someone.

Big danger with cars is their bumpers blowing off. A fully involved car isn't going to be explosive. Fumes are very nasty.

If you want an explosion, I'd make the truck a propane truck. If one of them blows, about 100 feet is going to be the danger zone. At that distance, you'll feel the heat and blast wave, may be knocked down, but will probably survive. Your shorts are going to be stained. There are a fair amount of videos of propane explosions on the web.

Best of luck,

Jim Clark-Dawe

Paramite Pie
04-04-2015, 09:03 PM
I was at a stunt-show where a vehicle was blown up, and despite being several rows back in the audience, the heat was intense. I could have been in an oven it was so hot! However the planned explosion would've been much larger than a natural explosion.
I honestly couldn't wait for them to extinguish the flames.

Its like when a helicopter is taking off and the 'wind' from the helicopter is really strong even when your many metres away. The immediate explosion was brief but almost unbearable. The heat from the flames afterwards really traveled. However, a real life explosion is probably quite dull by comparison.

Los Pollos Hermanos
04-04-2015, 09:43 PM
Cheers for the extra info, folks!

I don't need a big explosion, but I do need one of the cars to ignite as I need the driver of the station wagon to meet an unpleasant demise. There'll be Big Fallout from that later on. A petrol/gasoline car (rather than diesel) is needed here - those short-chain hydrocarbons are nice and volatile! (just been covering that stuff with my year 10s (9th grade equivalent)). I think I'll mention a wave of heat, but not go into much detail.

However, should I ever need a big bang in the future, propane it will be! And, there'll be a flying bumper (called a fender in the US?) and a few popping tyres in this scene.

The delivery truck driver manages to get out of his vehicle and stagger away to safety. One of the cops runs over to help. That's for a bit of authenticity - the unnamed truck driver isn't ever mentioned again. The three cops are in a surveillance vehicle halfway down the block, so it's just coincidence they're there when the collision occurs.

And the smells... I know the smell of burning rubber. When I was a teenager a lorry carrying loads of tyres caught fire on the M25 (about half a mile across the fields from where I used to live) and stunk out the whole village.

Thanks again,

LPH.

Los Pollos Hermanos
04-05-2015, 04:09 AM
Am now considering an empty propane truck...

http://nelsonrozier.blogspot.co.uk/2011/09/highway-166-propane-truck-crash-ends-in.html

Any thoughts?

:idea:

jclarkdawe
04-06-2015, 07:37 AM
In the US, bumpers are on the front and rear of all vehicles, and are often chrome. They're designed for front and rear end collisions, and have to be able to survive a 5 mph crash without needing fixing. To do this, they have pistons that absorb the shock. Problem is when these pistons heat up, they can explode, launching the bumpers with lethal force for a couple of hundred feet. Trajectory will be in line with the car. You can also have this problem with hatchbacks, but they're a lot less likely to travel in a lethal direction.

Fenders go around the wheels.

Cars burn with a variety of smells. You've got the rubber, but you have a bunch of plastic, sometimes aluminum, some sound proofing material, and then the seats. Smoke from cars is incredibly nasty, and a lot of it poisonous. And then you'll throw in the steam from the hot water in the engine, which will let go when the radiator hoses start burning.

Best of luck,

Jim Clark-Dawe

Quickbread
04-06-2015, 11:51 AM
Gangbangers used to blow up cars behind my house, so I know the smell of burning cars well.

It's a very specific smell, mostly like plastic, but metallic and a bit chemical underlying that. It's noxious. I don't recall rubber being too prominent. But it buns in your nose and throat, and it lingers in the air and surrounding ground for a long time afterward.

Los Pollos Hermanos
04-06-2015, 04:04 PM
Cheers for the extra info!

I've changed the delivery truck into an empty propane truck to make things more explosive, but not as explosive as if it was full of propane (according to my research). I need the station wagon driver to meet a grisly end, so can't have the flames "gentle" enough for anyone trapped to be rescued. The truck driver isn't needed, so I suppose it doesn't matter if he also ends up crispy.

Hmmm, methinks I've been spending too much time in the company of Mr Bad Guy recently!

One of the cops starts approaching, but quickly realises there's nothing he can do and backs off (the emergency services haven't arrived yet). I've already written that the fumes catch the back of his throat - would they also make his eyes water?

Big thanks!

LPH.

Quickbread
04-06-2015, 08:21 PM
I think eye watering is feasible for sure because of the chemicals. Choking/coughing on the fumes would also be likely if the cop was close enough or down wind from the smoke.

asroc
04-06-2015, 09:05 PM
One of the cops starts approaching, but quickly realises there's nothing he can do and backs off (the emergency services haven't arrived yet). I've already written that the fumes catch the back of his throat - would they also make his eyes water?

Big thanks!

LPH.

Most likely.

Regarding the smell, if neither of the drivers get out, don't forget the smell of burning human.

Los Pollos Hermanos
04-06-2015, 09:32 PM
Smells like roast pork, apparently? I heard somewhere that a lot of firefighters can't eat roast pork because of its smell.

:(

He's done a bit of coughing, although thankfully the scene ends before anyone gets too crispy...

asroc
04-06-2015, 09:38 PM
Mostly, yes. There's also something extra, probably the smell of burning hair, that's kind of indescribable but really bad. I think it's what makes the smell so inherently wrong.

Los Pollos Hermanos
04-06-2015, 10:14 PM
Burning hair smells vile - a girl in my (high school) chemistry class didn't tie her hair back when lighting a Bunsen burner... I can't describe the smell either, but it was nasty.

Cheers,

LPH.

fyrefyghter33
04-07-2015, 07:53 AM
I have been a volunteer firefighter for about 18+ years. So here's my two cents.

As mentioned a couple of times above cars do not explode unless there is something explosive in them.

It is rare for an accident to cause a car fire. I have only personally been to two incidents where this was the case. Usually it's bad wiring or arson that cases vehicle fires.

Car fires have a very distinctive smell. It is really hard to describe you have to experience that one for yourself.

Eye watering is [I]very[I] plausible, smoke, any type of smoke is an irritant and will turn your eyes into Niagara falls quite quickly.

I have never actually smelt burning hair at a fire. You however will never forget the smell of a burning body. I always thought it smelt more like frying ham sausage than roast pork. Every time it happens to me it can take me up to two months before I can eat sausages or bacon again.

If your propane truck gets into an accident and the tank is damaged enough to cause a hole or tear the propane will burn and your driver will not survive. I have seen it. Propane truck vs train. There wasn't much left of the truck driver.

Everything else you've written seems plausible. I hope I was helpful.

Los Pollos Hermanos
04-09-2015, 02:49 PM
Thanks for the insider info. There is something "dodgy" about the station wagon, but that all comes out in the wash later in the story. It's a shame it had to collide with an empty propane truck of all things! ;)

Morbid question: How far does the smell of crispy human travel? Two of my cops kept their distance, but one tried to get closer to see if there was anything he could do to rescue either driver - he quickly realised this wasn't an option and retreated.

I'll have to incorporate a brief something in the next few chapters about him not being able to eat the bacon/sausages his wife was cooking for breakfast. Whether the other two also develop the same aversion depends how far the smell travelled.

Cheers,

LPH.

King Neptune
04-09-2015, 05:04 PM
Thanks for the insider info. There is something "dodgy" about the station wagon, but that all comes out on the wash later in the story. It's a shame it had to collide with an empty propane truck of all things! ;)

Morbid question: How far does the smell of crispy human travel? Two of my cops kept their distance, but one tried to get closer to see if there was anything he could do to rescue either driver - he quickly realised this wasn't an option and retreated.

I'll have to incorporate a brief something in the next few chapters about him not being able to eat the bacon/sausages his wife was cooking for breakfast. Whether the other two also develop the same aversion depends how far the smell travelled.


The smell would travel as far as the plume of smoke travelled, and the cloud of smoke would include rubber and other things. Anyone nearby would retreat upwind of the fire.

Los Pollos Hermanos
04-09-2015, 06:10 PM
Looks like they'll be cancelling that hog roast...

Cheers,

LPH.

cmhbob
04-09-2015, 08:55 PM
I can tell you from experience that the smell from a crematory will fill the parking lot of the funeral home. It may drift farther than that (and this is a controlled, high-temp burn, with a tall (40') filtered smokestack with little visible smoke), but smell is very contextual. If you were five block away from the funeral home, and didn't know there was a crematory there, you'd think, "Wow, someone's got a nice cookout going."

Then you wonder why someone is grilling at 2 in the afternoon.

Los Pollos Hermanos
04-09-2015, 09:35 PM
I bet I'm on a watch list after googling this:

http://www.slate.com/articles/news_and_politics/explainer/2007/03/barbyou.html

:evil

Cheers,

LPH.

King Neptune
04-09-2015, 10:58 PM
I bet I'm on a watch list after googling this:

http://www.slate.com/articles/news_and_politics/explainer/2007/03/barbyou.html

:evil

Cheers,

LPH.

Humans are widely known as "long pig" among cannibals, but they wouldn't be eating all parts, just the meat.

fyrefyghter33
04-10-2015, 05:51 AM
The smell of the fire will mask the bodies smell. But after the car is out out and the smoke dissipates the smell will carry (depending on wind) 20+ ft.

I like the idea of your MC not being able to eat breakfast after. Seeing something like this can really have an affect on people. I've seen people lose their lunch just getting a little whiff.

Los Pollos Hermanos
04-10-2015, 10:26 PM
Oh yes, he's not going to appreciate the offer of a cooked breakfast (the next time this posse of cops feature)... ;)

Cheers,

LPH.