You have a particular interest in marine biology, but you are tired of reading about it in books and watching it on the National Geographic Channel. You are ready to get out into the sea and take a dive. However, every time you think about strapping on the gear, the image of Jaws exploding with a scuba tank in his mouth keeps haunting you into inactivity.
Scuba tank explosions are not a myth. Under the right set of circumstances, the highly pressurized air in a scuba tank could explode, causing as much damage as approximately 300 grams of dynamite. While scuba tanks can explode, it is extremely unlikely that scuba tanks will explode.
Scuba tanks have been tested as safe and effective over many years of use. Nonetheless, the safety of any object, especially those containing 3,000 psi of pressurized air, diminishes rapidly if not used properly, so safe handling is essential when using scuba tanks. Regular testing of tanks is discussed in our article on 14 steps for testing tanks.
Can Scuba Tanks Really Explode?
Yes, scuba tanks can really explode.
Now, the “explosion” that takes place from a malfunctioning scuba tank is not necessarily the kind of explosion where there is a lot of fireworks and incineration (unless the tank was filled with an explosive gas, other than the air used to fill a standard scuba tank).
The “explosion” that takes place from scuba tanks is due to the instantaneous release of so much pressurized air, creating a high speed and dangerous projectile that will cause chaos to anything in its surrounding area. If this exploding take were to come into contact with flammable items, then a traditional explosion could take place.
Scuba tanks are made out of either steel or an aluminum alloy. There are some pros and cons of each type of tank.
Steel Scuba Tanks
Pros: These tanks are extremely tough and hard to penetrate. They are also highly resistant to changes in pressure. Because steel is such a strong material, steel scuba tanks can often be more lightweight than tanks made from aluminum alloy, making for a more enjoyable diving experience.
Cons: The only real downside to using a steel scuba tank is that the corrosive properties of saltwater can wreak havoc on it. Your steel scuba tank should be rigorously cleaned between dives to make sure saltwater does not rest on the surface. If you are a person who frequently dives, you may have to replace your scuba tank often, as rust may become an issue.
Aluminum Alloy Scuba Tanks
Pros: These tanks are far more resistant to saltwater’s corrosive properties than are steel scuba tanks. In fact, if any rust does form on these tanks, it actually sits on the outside of the top layer and works as further protection for the tank, as opposed to eating away at the tank’s construction.
Cons: Aluminum is not as tough as steel, so an aluminum alloy tank may be at greater risk to physical damage or increases in pressure than its steel counterpart. Moreover, as aluminum is much softer than steel, more walls must be added to the tank, making it the heavier option.
While each type of scuba tank has its pros and cons, the vast majority of scuba tanks are made from an aluminum alloy, as the resistance to saltwater’s corrosive properties is seen as favorable to the benefits offered from a steel tank.
Still, regardless of what your tank is made of, each type may possibly “explode” if the perfect storm of unfavorable circumstances were to arrive. Let’s look at what could theoretically cause a scuba tank to explode and see whether or not specific factors pose greater risks for steel or aluminum alloy scuba tanks.
In this controlled test, a scuba tank was overfilled on purpose till burst point. For US readers, 100 bar = 1,450 psi. Scuba tanks are generally filled to 3,000 psi for use.
Increases in Tank Pressure
Scuba tanks are pressurized to release air to divers as they explore the depths of the sea. Most tanks are calibrated to be able to hold pressurized air of 3,000 psi (pound-force per square inch). To put that in perspective, an inflated football holds about 13 psi of air, and a car tire holds about 32 psi of air, so scuba tanks can hold some serious pressure.
If you try to overfill your scuba tank, you could run the risk of making it explode. However, this is extremely unlikely, as scuba tanks come equipped with a burst disc, which detects abnormally high pressure in the tank and ruptures before the tank itself does and, in doing so, prevents the introduction of more pressure to the tank.
Burst discs are typically rated at 140 percent of the scuba tank’s pressure, so a 3,000 psi tank would need to be filled to 4,200 psi before the burst disc would even rupture, let alone the tank itself. Nonetheless, if, for some reason, the burst disc were faulty and someone tried to fill their scuba tank up to a crazy psi very quickly, it could theoretically explode.
Although excessive air pressure is unlikely to cause either steel or aluminum alloy tanks to explode, the threat would be greater for aluminum alloy tanks, as they are not as durable as steel tanks.
One final note on this topic: some divers are concerned that leaving their tanks exposed to high temperatures could create an increase in air pressure that would cause the tank to explode. While high temperatures do increase air pressure, there is no way you could get your tank hot enough in a normal situation to make this type of explosion even a remote possibility.
Broken valves present the greatest likelihood of a scuba tank “explosion” and are equally likely to occur in both steel tanks and aluminum alloy tanks.
The valve is the most critical and delicate part of a scuba tank. It allows for a controlled release of pressurized air from the tank to the diver. As such, any malfunction of the valve, especially when you are out for a dive, would become critical.
A broken valve would be any situation in which the valve could no longer safely control the release of air and is most likely the result of a high impact, jarring collision.
When the air starts to release in an uncontrolled manner, the effect of all of that pressurized air can become quite destructive, causing the tank to do significant damage in a very short time to whatever may be in its path.
Rusted or Corroded Casing
This will be a possible threat for steel tanks, but not aluminum alloy tanks.
If for some reason, you have completely neglected cleaning your steel case in between dives, in addition to failure to pay attention to its overall condition, then there is a risk that normal tank pressure could cause a rusted tank to burst.
The iconic exploding scuba tank scene from Jaws involved a person shooting a hole in the tank in Jaws’ mouth, leading to a great explosion that led to the demise of cinema’s greatest sea villain.
Hollywood was correct in that shooting a hole in a scuba tank placed in a shark’s mouth would kill the shark. However, it would be due to the tank thrusting through a vital organ at such a speed that the shark would eventually die, and not because the shark’s mouth burst into flames.
This would obviously be a greater threat for the softer aluminum alloy tanks than steel tanks, but the chances of you trying to drill a hole in your pressurized scuba tank or getting involved in a situation where your tank might get shot are highly unlikely (one would hope). Be sure to watch the slow motion at the end.
Are Scuba Tanks Dangerous?
In short, yes, scuba tanks are dangerous. When handling an object that contains 3,000 psi of air, there is some risk in the event that something were to go wrong.
However, with proper care, use, and even a moderate concern for avoiding extreme situations, you will safely be able to use your scuba tank and enjoy exploring the sea.