[Spokehead87]

Could someone explain to me why tanks have expiration dates/time limits and if a tank is usable beyond that time limit?

[bikerjake805]

from my knowledge, tanks have "re-hydro dates" because you need to make sure the shell itself is still strong enough to hold the HEAVY pressure being put inside. its all for safety. newer tanks are 5 years from the date on tank and i believe its after 11-13 years that the tank should be tossed.

(dont quote me on that last part) but ya for safety reasons and no..if a tank is obvious old and worn..DO NOT FILL IT

[AHFellows]

Originally Posted by bikerjake805

from my knowledge, tanks have "re-hydro dates" because you need to make sure the shell itself is still strong enough to hold the HEAVY pressure being put inside. its all for safety. newer tanks are 5 years from the date on tank and i believe its after 11-13 years that the tank should be tossed.

(dont quote me on that last part) but ya for safety reasons and no..if a tank is obvious old and worn..DO NOT FILL IT

Think it might be 15 years and toss it, 11-13 would probably be safer though, but you got it, its basically to test the integrity of the tank under high pressure. When a tank is hydro tested they fill the tank with water (obviously, hydro) to a PSI over the max pressure of the tank (not sure how much over) This basically causes the tank to swell and the tank itself will actually get a little bigger. During this phase any weakness in the tanks integrity should cause it to have a blow out and the tank will rupture. If nothing happens then the tank will be deemed serviceable and will get your ugly new label epoxied on the tank. (this is how it was explained to me at my local place, hope its accurate.)

[flashoverride]

Pretty much, alot of what AHFellows said. Remember, air tanks take in air, and hold it at a high pressure. Typical pressure of the air around you is something like 6 PSI. So when you fill a tank with air, at 100 PSI, you are filling it to handle something that is already at a higher pressure than everything else around it. Fill it to 3000 PSI, or 4500 PSI, especially on a regular basis, and you have to make sure that the tank can handle the pressure.

Hydro tests, done every three or five years, are there to make sure that the tank can handle the strain of being filled regularly, as well as emptied. But carbon fiber and fiberglass tanks can only handle this for so long. So they have a 15 year lifespan. Anything after that, one would risk failure of the components and possible catastrophe. Steel tanks can last up to 24 years, before they are no longer structurally sound. Aluminum tanks though can last forever, as long as they pass their five year hydrotests. Honestly, if one could get a 68/4500 tank in all aluminum, without it weight a tone, and not being overly huge in size, that would be pretty cool. Buy one, and other than the hydrotests, it would last you forever.

That is if you still play after 15 years...

[Spokehead87]

This is all really helpful thanks for the info. I have a few aluminum tanks that haven't been used in 5+ years. Do I need to get those hydro-tested? Is it expensive?

Also, there is a guy who might give me a few nitro tanks that are 5+ years old but have rarely been used. Should I still get those tested?

Where can you get them tested?

[MaG Adrenal1ne]

Originally Posted by Spokehead87

This is all really helpful thanks for the info. I have a few aluminum tanks that haven't been used in 5+ years. Do I need to get those hydro-tested? Is it expensive?

Also, there is a guy who might give me a few nitro tanks that are 5+ years old but have rarely been used. Should I still get those tested?

Where can you get them tested?

Everything is base on a hydro date which is labeled on the tanks. I would personally look for a local scuba shop or something of the sorts to get your tanks rehydro'd. Even a local field.

[Spokehead87]

Ok cool we've got scuba places around here....even though I live in the he mountains. Thanks

[Tabris17]

Most cylinders have a max life span of 15 years with a rehydro every 3 to 5 years depending on their DOT number. The vast majority of new fiber cylinders these days are 5 year cylinders. At the 15 year mark it's an automatic fail by DOT regulations. A shop/field can not legally fill that tank for you; nor one out of hydro even if it's within the 15 year life span. It's a major violation that can carry a very serious and hefty fine if they are caught.
Metal cylinders are different and have many different rules and regulations. If it's a co2 cylinder, scrap it after 5-years and buy new ones. The price of the hydro is around the same as a brand new cylinder. Anything under 2" in diameter and two feet in length falls under the '2x2' rule meaning it is hydro exempt though it should be tested every 5 years for your own safety but it's not required. Then there are some tanks that don't have a lifespan at all.
You really need to check your DOT information because the laws or permits change every few years if a company doesn't renew them or the DOT themselves changes a law/rule.

[Spokehead87]

Originally Posted by Tabris17

Most cylinders have a max life span of 15 years with a rehydro every 3 to 5 years depending on their DOT number. The vast majority of new fiber cylinders these days are 5 year cylinders. At the 15 year mark it's an automatic fail by DOT regulations. A shop/field can not legally fill that tank for you; nor one out of hydro even if it's within the 15 year life span. It's a major violation that can carry a very serious and hefty fine if they are caught.
Metal cylinders are different and have many different rules and regulations. If it's a co2 cylinder, scrap it after 5-years and buy new ones. The price of the hydro is around the same as a brand new cylinder. Anything under 2" in diameter and two feet in length falls under the '2x2' rule meaning it is hydro exempt though it should be tested every 5 years for your own safety but it's not required. Then there are some tanks that don't have a lifespan at all.
You really need to check your DOT information because the laws or permits change every few years if a company doesn't renew them or the DOT themselves changes a law/rule.

So your saying that all CO2 tanks should be scrapped after 5 years, including aluminum ones?

[AHFellows]

Originally Posted by Spokehead87

So your saying that all CO2 tanks should be scrapped after 5 years, including aluminum ones?

No some Aluminum tanks can be used basically indefinitely some are exempt from being hydro tested others must still be tested(as long as they are in good condition of course.) Steel tanks I believe have a longer life than aluminum but don't quote me on that I haven't seen one of those since i had a 9oz back in the 90s thing weighed as much as a 90/45.

If your friend has carbon fiber tanks that have not been tested in 5 years then yes, by law you have to get them tested, and by law a field cannot fill them until you do so and as mentioned if their birth date is past 15 years they cant even be tested they must be thrown out.

Hydro testing varies on a few things, depending on who does it and how they get the tank. My local fire and safety place does mine for $25 with a 1-2 week turn around depending on how busy they are. They also will charge me $5 extra dollars if I take a tank in with a regulator on it that is not easily removable by a regular wrench and I have to sign something saying I will not hold them liable for tank damages while removing a regulator that is not easy to remove. Because of this I remove them myself. If you chose to send the tank off it may cost more for shipping charges which if you have the regulator on the tank must by law be sent ground only as it is a compressed air cylinder. So turn around may be even longer and may end up costing between 30-40 dollars.

As Tabris17 said though for your aluminum tanks it depends on DOTs certification of that tank. over all I would recommend getting a carbon fiber tank if it is in your budget though. much lighter and you will get many more shots per fill with a larger tank


Here is a list I found about some of the specifications

Aluminum Nitro or CO2 Cylinders: Aluminum cylinders with a "3AL" stamped in the crown of the tank must be hydrotested every 5 years. These cylinders have and unlimited life and never expire provided they pass the hydrotest certification. Cylinders 2 inches in diameter or less and less than 2 feet long are exempt and do not have to be rehydrotested.

Fiber Wrapped or Carbon Fiber Nitrogen TankS: Fiber wrapped/Carbon Fiber cylinders must be recertified every 3 or 5 years depending upon the specific D.O.T. Exception Regulation ("E" number) on the cylinder's label. (See Table Below). These cylinders have a maximum life span of 15 years after which they are retired.
"E" Number Manufacturer HydroTest Schedule
E-07277 SCI Every 3 Years
E-10945 SCI 3 Years if last tested before July 1, 2001.
5 Years if newer than or last tested after July 1, 2001.
E-09634 LUXFER Every 3 Years
E-12479 LUXFER Every 3 Years
E-10915 LUXFER 3 Years if last tested before May 11, 2001.
5 Years if newer than or last tested after May 11, 2001
E-11005 Carleton Every 3 Years
E-11194 Carleton 3 Years if last tested before July 1, 2001.
5 Years if newer than or last tested after July 1, 2001.
E-12695 Global Composites International D.O.T has decertified. Cannot be filled or used any longer.

Steel Nitrogen Tanks: Steel cylinders with a "3HT" stamped into the crown of the cylinder must be retested every 3 years. These cylinders have a maximum life span of 24 years after which they are retired.


Fun fact
also looked up when Hydro tested tanks are filled to 1.5 times the max pressure rating.

[flashoverride]

Originally Posted by Spokehead87

So your saying that all CO2 tanks should be scrapped after 5 years, including aluminum ones?

Not saying that they should be, just that for the cost, it will cost around the same amount of money to have the tank hydrotested as it will to just buy a new one. Actually, it may be more money to do the hydrotest. There are a few places that will do a hydro for less than $22, but often, it will only cost between $20-25 for a brand new CO2 tank, depending upon size.

Aluminum will be good as long as it passes hydro, steel has a lifespan of 24 years. AHFellows shows that with his copy and paste of some of the DOT info.

[Spokehead87]

Thank you guys. This is enormously helpful.