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Elevator and Escalator Consulting Engineers

Trapped?

Countless stories and films have as their central thesis some poor souls trapped in an elevator for hours or days. In real life anyone who has been trapped in an elevator will tell you that it is not a pleasant experience. There is the complete cut-off from the rest of the world, the confined space, the lack of sensory stimulation and the lurking threat of the elevator crashing to the ground. Somewhat like an isolation cell on Death Row.

In fact, you are probably safer trapped in an elevator - barring the lack of food and water - than walking outside on the street. Those of us in the elevator industry know that but people not in the industry remain sceptical. The injury related to entrapments occur when the person trapped attempts to escape from the elevator. If the trapped passenger waits until the elevator is restored to service there is no danger. This, of course, excludes buildings on fire and such similar events. As well, waiting for what might be several hours is not easy to accept.

What are the chances of getting trapped in an elevator?

Assume that you work in an office building where you use the elevators 8 times per day and that each trip takes 30 seconds. In a given month of perhaps 20 working days you would be on an elevator 4,800 seconds or 80 minutes. This is out of (assuming a 10 hour building operating day) 12,000 minutes per month of elevator operation.

On the average for a well maintained elevator installation we would expect about 0.03 entrapments per month per unit. So if your exposure is (as above) 80 minutes in 12,000 minutes of elevator operation then you have a probability of entrapment each month of 0.02% or 1 in 5,000. To put this in some sort of context the odds that you will be struck by lightning in any given month are 1 in 3,360,000. So you are about 670 times more likely to be trapped in an elevator than being struck by lightning. Probably, from a risk management point of view, since the consequences of the two events can be dramatically different, most people would opt for the risk of entrapment rather than the risk of being struck by lightning. Incidentally, the odds of being trapped in an elevator and being struck by lightning at the same time are astronomical but it is possible that you might be trapped in an elevator during an intense lightning storm (without the lightning actually striking you) since these storms will occasionally, although rarely, affect the elevator system.

Of course, if you work for 25 years in this same building taking these same elevators by the time you have received your gold watch (or simply been declared redundant) your chances of entrapment go up to about 1 in 17. Which means that if you are one of a group of 17 colleagues working in the same building for the same length of time then the probability is that one of you will have a horror story to tell about the time “I was trapped in an elevator”. Which should be good for the occasional free drink if not a free dinner.