Vaults—especially bank vaults—are designed to be air-tight, and not where humans are expected to stay for extended periods. On a recent visit to a safe-deposit vault at a bank I found myself alone while putting away my valuables. I wondered: how long could I survive in a bank vault if I was trapped in one? What I found surprised me.
You may survive about 17 hours or more if you are inadvertently trapped in a vault or large airtight rooms. But it is unlikely you will survive more than 72 hours. This means if you are locked in a bank vault over a 3-day weekend for example, when the bank is closed for business, it is likely you will not survive. The actual time you survive depends on a variety of factors.
Let’s look at what increases your chances of survival and what you could do if you were trapped. Surviving in a bank vault is similar to surviving an extended period in an airtight space. The key factors are:
- Dehydration and thirst—because vaults are designed to be low humidity to keep valuables and documents in good condition. Bank often have ventilation to keep temperature and humidity levels low.
- Suffocation—because air-tight or restricted air ventilation can result in dangerously high levels of carbon-dioxide that can kill you. Lack of oxygen, which is at a higher concentration than carbon-dioxide, is often less of a factor.
Human beings can live for 3 weeks without food, but only 2 to 3 days without water. A lack of food, though uncomfortable, should be the least of your concerns. Obviously, your special circumstances like critical daily medication can also be a factor.
3 Things to Do If You are Trapped in A Vault
- Focus on being found rather than trying to get out. The most urgent issue is to alert someone as soon as possible. After all whoever let you in, is your best bet to let you out. Search for emergency features to alert others that you are trapped: emergency release switches or button, intercoms or landline phones, fire alarms, hidden burglar alarms etc. Try 911 on your cell phone though it is likely you won’t get a connection or wifi in a vault. If you see a sprinkler system, see if you can activate it to set off an alarm. If you see a security camera try disabling it to catch someone’s attention. If all fails, don’t even think of getting out: that’s for the movies. Vaults are secure and you are unlikely to find an easy way to get out.
- Control your breathing to reduce carbon dioxide levels in the vault. Knowing that a high level of carbon dioxide is your number one risk, conserve your energy and lower your breathing rate by reducing your activity level. This includes sleeping and reducing movement. Try not to panic, which will increase your breathing rate. If you are lucky the ventilation in the vault might keep you alive for a long time. Carbon dioxide concentration is about 0.036% in air, and toxic at 10% at which point it leads to convulsions and death. Carbon dioxide is also 1.5 times heavier than air so climbing up to a high point in the room may help.
- Dehydration and thirst are your enemies. The low humidity causes dehydration and makes your thirsty. If there is no sprinkler system, conserving your energy also reduces thirst and increases your chance of surviving at least 2-3 days. Your obvious thought might be to look for other sources of water—like you! But drinking your pee can kill you. As the Army Field Manual points out, drinking your pee (which is 95% water with high levels of sodium and other salts) is like drinking seawater (96.5% water) which will dehydrate you further.
You can survive being locked in a vault if you act quickly and focus on being found, rather than trying to get out. The first few minutes are likely to be crucial as someone is likely to be around after having let you into the vault. If you are stranded and locked in, your best bet is to stay calm, conserve energy and focus on surviving by reducing your breathing rate and combating thirst. Do this, and you may survive for 17 hours or more.