I was stuck in a lift (or elevator) today with two very attractive women. Ordinarily, most men would generally regard this as a good thing, as would I have done, were it not for three pertinent factors.
I’m extremely claustrophobic.
The lift was extremely small. It’s dimensions were about 7 foot high by three foot wide by two foot broad - or 210 centimeters high by 90 centimeters wide by 60 centimeters broad.
There was absolutely no airflow into the lift. I mean none whatsoever.
I’ve worked out that the volume of the lift was 1,134,000 cm[sup]3[/sup]. This, however, is based on what I believe to be a slightly generous overestimate of the lift’s proportions (I neglected to bring a tape measure).
My question is, would it be possible to roughly estimate how many minutes of breathable air we had based on the above information? We three are all of average build. We managed to get out after about fifteen minutes.
It is possible to figure out how much oxygen you had. However, I feel it is important to point out that you would not have suffocated, but would have instead died from excess CO2 in such a large space. Furthermore, it is highly likely that there was significant air exchange with the outside air, even though you aren’t aware of it (like in a house).
I’m sorry. I’ve realised while looking into this just how utterly pathetic my basic mathematics skills are. I’m getting woefully confused by this.
The formula in your cite calculates the amount of safe, breathable air in any given space as follows:
T = The number of hours of breathable air in any given space.
(Volume of air inside the room in cubic feet) x (3% or 0.03)
T = -----------------------------------------------------------------------------
(Number of people) x (one person's hourly production of CO2)
Now, the dimensions of the lift were 7 feet by 3 feet by 2 feet. To find out the volume of a cuboid, you multiply these dimensions. 7x3x2 = 42. That means there was 42 cubic feet of air in that lift.
42 multiplied by 0.03 = 1.26
The cite gives one person’s hourly production of CO2 as 1.7 cubic feet per hour.
There were three people in the lift. 3x1.7 = 5.1
So the formula is T = 1.26 divided by 5.1
That gives 0.24705. Now, that’s 0.24705% of one hour, which is approximately 15 minutes.
According to your cite, we were let out of the lift at a point just before the amount of CO2 in the lift became toxic.
Am I going wrong? Because that’s a bit unnerving. I take your point that there was probably some air exchange I didn’t know about but I’m confident that any air exchange which did take place would have been quite small. The roof of the lift was stuck on pretty tightly, and the only break in the seal was a tiny space at the bottom of the door, which itself seemed to be sealed by the inside of the lift shaft. As such, the beneficial effects of any air exchange may have been outweighed by the amount of CO2 we were producing.
Bearing in mind that I’m dreadful at maths, can you see any mistakes in my reasoning?
Compare the size of one of your nostrils to the area of the slit under the door. Then figure that between six lungs pumping and big weighty masses moving around, there’s actually going to be a decent amount of in-out movements of the air through that slit. That’s going to mix the air up pretty decently.
Also, a 2’ x 3’ floor space for three people seems too small. I would almost be touching the front and back of the elevator at the same time, and the two ladies would have to be about 6" across the shoulders each.
7 x 3 x 2 is a coffin. What kind of elevator is this, and if it’s actually that small, how (and why) did you fit three people in it?
In your calculation you forgot to subtract out the volume of breathable air displaced by the people in the lift. Estimating the human body to have a density roughly equal to water, a 160 lb person would have a volume of about 2.5 cubic feet, which would knock your mean time to death down by about 20%.
I agree with inv1188 that 3 people in a 2x3 ft space sonds quite…cozy.
Mix, yes, but theoretically breathing doesn’t produce in-out. The air in your lungs takes up the same amount of space as the surrounding air.
But that’s unimportant because, as DrDeth just noted, elevators aren’t sealed, so there must have been some circulation, and the OP wasn’t in danger of suffocating.
Granted, Randi trained and relaxed himself for the stunt.
We sort of made a triangle shape. One girl stood against the back, I stood facing her with one shoulder touching the door and the other shoulder facing the left wall, the third girl did the same on her side. If it sounds ridiculous, that’s because it is. This is easily the smallest lift I’ve ever, ever seen. God knows why I decided to get in it.
It was cozy! Seriously, you should see this thing. It’s minute. At one point one of the girls knelt down to reach into her handbag and grab her phone and she couldn’t turn her head without bumping into the wall on one side and my crotch on the other
Well, I’d be very happy to take your word for that
This may be unrelated but the temperature in the lift absolutely shot up in the fifteen minutes we were in there. Is that indicative of anything other than the fact that our body heat wasn’t able to dissipate properly? I’ve heard that as air gets less breathable your body temperature rises.
Sounds like the premise for a porn movie. ‘Perhaps if we began breathing harder the air in the lift would circulate faster.’ What to do to increase our breathing rate…?
This is correct. You may not be able to see it but in the top of the car is an exhaust fan, And around the bottom are air inlet slits (those you will not see from inside the car. Even if the fan is off there is a natural draft through the car.
Oh if the system is working properly you are not going to fill a draft. You would probably be introuble with other body function before the CO2 build up would even give you a head ache.
You can think about it this way- a typical scuba tank (say, an 80) has about the same amount of air as is contained in a phone booth, and lasts a typical diver about an hour at a depth of less than 75 feet or so. So I guess you could survive at least an hour in a sealed phone booth…
Which, on preview, seems to match Randi’s 1955 experiment pretty closely…
In all seriousness, the lift in my office is roughly about that size. Maybe a little bigger, but certainly not so much that you’d notice if you were to see a photo of each side by side.
I’m sure Snnipe is right (after all, I can’t imagine the engineers who rigged the thing up wouldn’t have considered the obvious dangers posed by omitting at least some method of air exchange), but for what it’s worth I’m posting from the UK and I happen to know that that lift was built in the early 80’s.
