Could you suffocate in a car?
Discussion
Help settle a debate with my mate pls
My friend says if you were to sleep in (or get trapped in) a modern car with the windows up and the engine off, you'd be in danger of suffocation eventually since modern cars front vent doors go into the closed position automatically when the car is off, sealing off the cabin and resulting in an Air Exchange Rate of 0.01 meaning the air is replenished every 100 hours, which he tells me would be too slow to prevent dangerous CO2 buildup and O2 depletion.
Is this true? I don't know all that much about cars but interested to learn
And do the HVAC vent intake flaps go into the CLOSED/RECIRC position when the car is off? seems like a feature that'd go against safety guidelines to me
edit: Nobody's claiming cars are airtight. relying on "cars are not airtight" seems a bit shortsighted to me since the argument is the air exchange rate would be low enough that CO2 could build up to dangerous levels, or O2 could be depleted faster than it's coming inside the car.
In short:
Not airtight ≠ adequate ventilation to prevent the possibility of suffocation
My friend says if you were to sleep in (or get trapped in) a modern car with the windows up and the engine off, you'd be in danger of suffocation eventually since modern cars front vent doors go into the closed position automatically when the car is off, sealing off the cabin and resulting in an Air Exchange Rate of 0.01 meaning the air is replenished every 100 hours, which he tells me would be too slow to prevent dangerous CO2 buildup and O2 depletion.
Is this true? I don't know all that much about cars but interested to learn
And do the HVAC vent intake flaps go into the CLOSED/RECIRC position when the car is off? seems like a feature that'd go against safety guidelines to me
Edited by InquisiSquid on Sunday 6th September 16:37
edit: Nobody's claiming cars are airtight. relying on "cars are not airtight" seems a bit shortsighted to me since the argument is the air exchange rate would be low enough that CO2 could build up to dangerous levels, or O2 could be depleted faster than it's coming inside the car.
In short:
Not airtight ≠ adequate ventilation to prevent the possibility of suffocation
Edited by InquisiSquid on Sunday 6th September 18:27
A truck interior isn't much larger than a car, indeed back in the days of day cabs when drivers slept on planks of word across the bonnet the cabs were tiny, in many cases the drivers have no air vents open especially in winter, can't recall any of the thousands of overnighters dying through suffocation but might have been a few through CO poisoning with poorly maintained/fitted night heaters.
cliffords said:
I watched a parked and locked car get submerged by an incoming tide . When the car was retrieved at low tide and towed up the beach, the car has been full of water and had a fair bit of sand in it . It was certainly not water tight.
No fishes.
That's a good point if a car was airtight it would not sink easily. No fishes.
ARH said:
That's a good point if a car was airtight it would not sink easily.
my mate isn't claiming cars are airtight though. an air exchange rate of 0.01 like my mate said isn't 0. his argument was the air exchange rate is low enough that you'd use up o2 and exhale co2 faster than the air is being replenished InquisiSquid said:
ARH said:
That's a good point if a car was airtight it would not sink easily.
my mate isn't claiming cars are airtight though. an air exchange rate of 0.01 like my mate said isn't 0. his argument was the air exchange rate is low enough that you'd use up o2 and exhale co2 faster than the air is being replenished Well if nobody else is going to, I'll tell the old joke about suffocating in cars.
A German, a French, and an Italian automotive engineer met for a drink, and were surprised to learn that they each tested the quality of their cars by shutting a songbird in them for a week. The German was happy if the songbird was dead, as this demonstrated that precision engineering had resulted in a perfectly airtight car. The Frenchman was happy if the songbird was singing, as that showed it was imbued with joie de vivre by his car. The Italian engineer was happy if the songbird was still in there.
A German, a French, and an Italian automotive engineer met for a drink, and were surprised to learn that they each tested the quality of their cars by shutting a songbird in them for a week. The German was happy if the songbird was dead, as this demonstrated that precision engineering had resulted in a perfectly airtight car. The Frenchman was happy if the songbird was singing, as that showed it was imbued with joie de vivre by his car. The Italian engineer was happy if the songbird was still in there.
Otispunkmeyer said:
It might get stuffy but I'm sure there are interior vents, usually in the back/boot that are there for allowing the air out when you close a door. So air can get in still.
Exactly this.... if they were air tight then slamming a door closed might be a tad tricky.... MDT said:
Otispunkmeyer said:
It might get stuffy but I'm sure there are interior vents, usually in the back/boot that are there for allowing the air out when you close a door. So air can get in still.
Exactly this.... if they were air tight then slamming a door closed might be a tad tricky.... MDT said:
Exactly this.... if they were air tight then slamming a door closed might be a tad tricky....
Nobody's claiming cars are airtight. relying on "cars are not airtight" seems a bit shortsighted to me since the argument is the air exchange rate would be low enough that CO2 could build up to dangerous levels, or O2 could be depleted faster than it's coming inside the car.In short:
Not airtight ≠ adequate ventilation to prevent the possibility of suffocation
Google seems to think a human uses about 500l of oxygen a day. Say a car interior is 2x2x1m that's 4000l of space. The atmosphere is 20% O2 so that would be 800l of O2. So even if it was completely airtight you'd be fine.
You're welcome to work out the precise interior volume of a remarkably well sealed MX5 to see if that would be an issue.
You're welcome to work out the precise interior volume of a remarkably well sealed MX5 to see if that would be an issue.
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