Tank Expiration - What next?

[aviator1912]

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[Highmarker]

Re: Tank Expiration - What next?

Aviator1912,

That is a good questions that hasn't been addressed.

Most tanks that were manufactured in the 90's and a few in early 00's are certified for 15 years. Most new tanks are certified for 20 years. The statement "Do not use after 2010" is real. Usually this statement includes a month also. At the end of the month of that year, the tank MUST be removed from service. The tank should be destroyed. There is NO re-hydrotesting of CNG tanks and returning them back into service.

Now, there is no "enforcement" of this ruling, but if you continue to use a tank that is past its expriation, then the liability is all on the you. The tank manufacturer, tank installer, and the tank inspector are all cleared of any liability.

[Curtis]

Re: Tank Expiration - What next?

The IANGV had posted some time back that their new international standard is 25 years, however that can vary from manufacturer to manufacturer.

I guess that they figured that these vehicles would probably be off the road with 15 years. They just hadn't counted on the tenacity of ngv owners.

[Luke]

Re: Tank Expiration - What next?

Highmarker,

I know you are working on the development of new CNG tanks. Any plans on making drop-in replacements, or ones that would otherwise fit in the place of expiring OEM tanks?

[Idarusskie]

Re: Tank Expiration - What next?

why don't they let you hydo test them? Like every other tank out there?

[Highmarker]

Re: Tank Expiration - What next?

CNGutah,

That is a good idea that we are considering. Right now we are solely focused getting through certification on our first CNG tank: 13 GGE ~18.9" diameter and ~57" long and ~280 lbs.

[Highmarker]

Re: Tank Expiration - What next?

Idarusskie,

All compressed gas tanks that are composite overwrapped have expiration dates. Even paintball cylinders and breathing tanks that firefighters use have expiration dates. Most are 15 years, but some have recieved an exemption from the DOT for upto 30 year life, but those are special cases. Those tank have to be re-hydrotested every 3-5 years. CNG tanks do not have to be re-hydrotested, mostly because they are stationary tanks and the specification doesn't require it.

So what do you want: A) a tank that has a 15 year life and you have to rehydrotest every 3-5 years (this means removing the tank from you car), or B) a tank that has a 20 year life and you don't have to rehydrotest every 3-5 years, just have to have it visually inspected every 3 years? I hope you choose B). Of course, that is currently what is being designed and accepted by the NGV community.

[MrComment]

Re: Tank Expiration - What next?

You could always "resize" your tanks to whatever is avaliable at the time. I'm sure there will be plenty of options available for you to choose from for much less the $10k. It just expessive when you get picky.

[freedml]

Re: Tank Expiration - What next?

At 15 years and 1 day the giant DOT hand comes down and punches a hole in your tank (after releasing the pressure slowly, of course).

[cngmike]

Re: Tank Expiration - What next?

When the 15 year life cycle came about it was figured on life cycles. The times that the tanks would be filled and emptied. As I remember it was 3 daily. Tom might know more about this. The folks at SCI said there new tanks are rated for 20 years they said that it is the same tanks, through cycle testing and safety records they were able to lobby for the longer rating. My vehicle os a 94 I don't yet know what I will do in 09. The Super Shuttle drivers felt cheated if they didn't get at least 300,000 mikes out of their vans.

[djkenney]

Re: Tank Expiration - What next?

When the 15 year life cycle came about it was figured on life cycles. The times that the tanks would be filled and emptied. As I remember it was 3 daily. Tom might know more about this. The folks at SCI said there new tanks are rated for 20 years they said that it is the same tanks, through cycle testing and safety records they were able to lobby for the longer rating. My vehicle os a 94 I don't yet know what I will do in 09. The Super Shuttle drivers felt cheated if they didn't get at least 300,000 mikes out of their vans.

Let's see if I understand this correctly. 15yrs X 365 days X 3 cycles/day = 16,500 cycles. If I go 200 miles on one tank, that would mean my tank is good until 3 million miles?

[Curtis]

Re: Tank Expiration - What next?

Let's see if I understand this correctly. 15yrs X 365 days X 3 cycles/day = 16,500 cycles. If I go 200 miles on one tank, that would mean my tank is good until 3 million miles?

You're 100% correct. The rule reads 3,000,000 miles, or when the expiration date comes up... whichever is first.

[josch]

Re: Tank Expiration - What next?

Aviator1912,

That is a good questions that hasn't been addressed.

Most tanks that were manufactured in the 90's and a few in early 00's are certified for 15 years. Most new tanks are certified for 20 years. The statement "Do not use after 2010" is real. Usually this statement includes a month also. At the end of the month of that year, the tank MUST be removed from service. The tank should be destroyed. There is NO re-hydrotesting of CNG tanks and returning them back into service.

Now, there is no "enforcement" of this ruling, but if you continue to use a tank that is past its expriation, then the liability is all on the you. The tank manufacturer, tank installer, and the tank inspector are all cleared of any liability.

You don't have to destroy the tank. You only have to drill like a 1/2" hole in it or something like that (can't remember the exact size or number of holes). Then you could still use the tank for other things like a decoration in your back yard, a buoy for your yacht, or halfway bury it in your flower bed, and cut one end off of it and plant flowers in it But you don't have to destroy it. That would be wasteful. We gotta think green