How long does a scuba tank last?

+3 votes
asked Jan 27, 2017 in Scuba Diving by Scuby Doo (45 points)
How old is too old to buy a tank and when do they expire?

3 Answers

+1 vote
answered Feb 23, 2017 by revgramza (1,095 points)
Scuba Tanks are controlled by the US Department of Transportation (DOT).

Every five years the tanks must go through hydrostatic testing.  A tank is filled to 5/3 its capacity with water.  A typical 3000 psi tank is filled with 5000 psi of water (inside an armored tank).  The steel or aluminum should flex under this pressure.  This flex is measured.

Every year the tank must undergo a visual test.  A certified tech will release the air, remove the valve and carefully inspect the inside and outside of the tank for corrosion and cracks.

The fact that tanks are required to be tested and inspected does not mean that they are.  If buying a tank look for when it was last hydro tested.  This will be stamped into the tank.  Look at when it was last visually tested.  This will be on a sticker.  A well maintained tank will have a very long life.  Aluminum tanks are engineered for 100,000 fills or 10,000 hydro tests.  In the end, they last until they fail a test, and then they are condemned.

I own many tanks.  When considering a purchase, take into account total cost of ownership.  Testing is not inexpensive and the cost of filling your tank is close to the cost of renting a full tank.
0 votes
answered Feb 17, 2017 by Deepbeastbeneath (100 points)
As long as the tank has been taken care of, regular visual inspections and hydrostatic tests done, then there isn't any "hard" cutoff on dates. When I was managing a dive shop we had a dive instructor who would proudly open up his tanks from the 40's and show everyone how clean they were. Now i'm not saying go out and buy ancient tanks but use common sense and have a professional evaluate them before buying.
0 votes
answered Apr 10, 2017 by George1224 (5,147 points)
Depends on whether its Steel or Aluminum. Aluminum tank dated prior to 1989 have in infereor alloy and can not be filled. Steel tanks that pass visual and Hydro can last indefinitely. you have to check the markings on the neck of the tank for pressure rating, manuf. date of manuf, material of construction and last hydro.
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