Can You Leave Scuba Tanks in the Car on a Hot Day?

can you leave scuba tanks in the car

On a scorching hot summer day, the heat can be so damaging that it can even cause your scuba gear to warp. We’ve all been told about the dangers posed by UV rays, however most of the time the context is in regards to how it can hurt humans. However, UV rays are known to discolor and weaken all sorts of materials from fabric to metal, and of course it can also cause heat damage. UV rays can get so intense that it can cause gear to warp, shrink, and generally become unusable or have their lifespan decreased.

When the sun is shining on a car parked outside, it can make the inside of the car feel like an oven even if the windows are cracked open. If you have a fully pressurized scuba tank inside, will this cause any sort of damage? Will the heat somehow cause the tank to fail, resulting in a serious accident? Can you leave scuba tanks in the car, or is this something to be avoided?

Yes, you can leave your scuba tank in the car, however it’s best if it’s covered up or out of direct sunlight so that it’s not exposed to the damaging UV rays. That said, if you are able to park somewhere with shade or have ventilation then obviously that’s preferable. However, the heat should not be so serious an issue as to cause any  damage to the scuba tank assuming it’s covered up.

What happens if you leave a scuba tank in the car when it’s hot?

sun harm wetsuits

The main issue with leaving a scuba tank to heat up in a car is that the air inside will expand even more, increasing the pressure inside . That means that if your tank is filled to 3,000 psi, it’s possible on a hot day that it reaches 3,100 psi, maybe a little more.

In our experience (plus talking with other divers and gathering their anecdotes), this has never been a serious issue. During a hydro test, the tank is pressurized far beyond its pressure rating, meaning there is some leeway if you do go over it. That’s not to say that we recommend doing so, but your tank can definitely withstand the change in pressure caused by the heat.

Are there any risks in an overpressurized scuba tank? It’s possible that a hot tank can cause the burst disk to blow, however we have never had that happen to us and neither have others. Also, if a tank is overpressurized, then it can cause the material to be heavily stressed and it will decrease your tank’s lifespan.

That said, the worst thing you can do is leave the scuba tank out in the open in direct sunlight, or place it next to something that generates a lot of heat such as a radiator or an exhaust. Especially in regards to leaving it in the sun, it will get significantly hotter than leaving it in the car covered up.

Furthermore, someone has claimed to have left their tanks in the car during outside temperatures of 45°C (113°F) with no issues, with many others sharing the same sentiment. I’m sure some people have similar or even more egregious stories. Note that this is not us recommending to leave your tanks in the car or suggesting that this is a good idea; just giving you some anecdotal evidence that it may not be as bad as it seems.

Parting words

If you have to leave your scuba tank in the car on a hot day for a long period of time, we recommend covering it up and rolling down the windows. If you are worried about an explosion or a burst disk blowing, then consider asking the dive shop not to completely fill the tank so that the increase in pressure from heat will not go over your tank’s pressure rating.

Based on our own experiences and others’ anecdotal experience, leaving scuba tanks in the car on a hot day does not seem to be an issue.