How Often Do SCUBA Tanks Need To Be Inspected & Tested?
Candace Reno September 20th, 2022 Posted In: Articles Tags: SCUBA
How Often Do SCUBA Tanks Need To Be Inspected And Tested?
You might be thinking of buying your own SCUBA tank. This decision usually comes with determining how often do SCUBA tanks need to be inspected and tested because this will add costs to owning your own tank. There are many different types of SCUBA tanks, but they all follow similar rules for inspection and testing. Before attempting to SCUBA dive, make sure you get certified. Let’s talk about the different types of inspections and tests needed to be done on SCUBA tanks.
The Making of a SCUBA Tank
In America, the U.S. department of transportation (DOT) controls SCUBA tanks. After they are made, they undergo DOT certification followed by a test. This test that all SCUBA tanks have to pass is similar to that of space certifications.
Visual Inspection
How often should a SCUBA tank be inspected? A visual inspection should be completed on your SCUBA tank once a year. This is done by a certified visual cylinder inspector. The date of the last vis, as we call it, that was performed is written on a sticker somewhere on the tank. During a visual inspection, the tank is bled dry slowly, the tank valve removed, and the inspector looks inside using a light source for any kind of corrosion, damage, or moisture. If a SCUBA tank fails a visual inspection, the tank is decommissioned.
Do Scuba Tanks Really Need to Be Inspected?
Yes! First, your safety is a priority. A tank that has not undergone a visual inspection in the last year is at risk of having moisture and damage in it. This could harm the diver using the air. Second, the safety of the person filling your tank is important. A tank that is out of visual inspection is at risk for causing damage during the air fill. Third, most, if not all, SCUBA air fill stations will reject an air fill for a SCUBA tank that is out of date with its visual inspection.
More Than Once a Year
Sometimes a SCUBA tank needs to be visually inspected more than once a year. This happens if the diver breathes down the air in the tank. A dry tank needs to be visually inspected before its next use because moisture may have gotten inside due to it being empty. This is one reason why dive operations will get upset if they find a diver has a tank that is completely empty. This is also very dangerous if the diver has breathed through the entire tank while diving.
Divers should always surface from a dive with 500 PSI in their SCUBA tank as added precaution for their safety while diving but also to help the SCUBA tank from getting moisture inside. However, other reasons could cause the SCUBA tank to become empty including accidental release of air while on land.
Hydrostatic Test
How often do SCUBA tanks need to be tested? A hydrostatic test is performed every 5 years for most tanks. Of course, there are always exceptions to the rules depending on the kind of tank and local laws. Some areas require the hydrostatic test to be performed on SCUBA tanks every 2-5 years.
During a hydrostatic test, the tank is filled to 5/3 of its normal filling capacity. For example, a 3000 PSI tank will be filled to 5000 PSI. However, the tank is filled with water not air! The tank valve is also replaced with a special hydraulic testing connection. This tests the flexing of the tank walls.
Water is used because it cannot be compressed. Air can be explosive if the tank were to fail this test. For extra safety, these hydrostatic tests are done inside armored vessels and while the tank is underwater. The amount of water in the column that rises is a measure of tank expansion. If a SCUBA tank does not adequately expand while under pressure, it fails the test and is decommissioned. During the failed test, the valve threads are usually what leads to the tank failure. Another common reason to fail a hydrostatic test is that the bottom of the tank will burst open due to corrosion. A failed test means the SCUBA tank can never be filled with air again.
Where Can I Get My SCUBA Tank Inspected and Tested?
I would say that all SCUBA dive shops have the ability to conduct a visual inspection of a SCUBA tank. Special training is involved to be an inspector, but a SCUBA shop really could not function without being able to inspect their own tanks.
Now that you know a little bit more about hydrostatic testing, it now makes more sense that SCUBA tanks are usually shipped out somewhere for their hydrostatic test. On rare occasions, a SCUBA dive shop may have the equipment and technicians to do hydrostatic testing on site.
How to Maintain Your Tanks
1. Always keep 500 PSI minimum in your tank
2. Have your tank filled only at a reputable air fill station
3. Store tank in a dry, cool place
4. Avoid lengthy direct sunlight exposure- heat kills tanks!
SCUBA divers often do not think of buying their own tank right away. Mask, snorkel, fins, booties, and wetsuits are usually bought first. However, there is something to be said of having every piece of gear you need for diving so that you do not rely on anyone else or a SCUBA shop to be able to just go out and dive!
I can support this information from personal experience. While snorkelling I came face to face with an enormous shark. Twice the size of me in every dimension. It saw me at the same time I saw it. I saw the shock wave go down its body at the same time as the shock wave went down mine. Our reactions were the same – we both turned round immediately and shot off in opposite directions.
Thanks for sharing your experience, John. I’m glad you lived to tell the tale!