New article about tank expiration...

[desimundo]

wwwDOTgovernment-fleetDOTcom/Article/Print/Story/2010/05/What-Happens-When-Your-CNG-Tanks-Expire.aspx

[jblue]

Re: New article about tank expiration...

Great article, thanks for sharing. Here is a clickable link:

http://www.government-fleet.com/Article/Print/Story/2010/05/What-Happens-When-Your-CNG-Tanks-Expire.aspx

[afvman]

Re: New article about tank expiration...

Greetings all,

The issue in my mind has always been the number of cycles (zero to full) NOT the number of years. Standards are based on design qualifications. In the case of NGV2 it's 11,250 cycles along with burst, bonfire, impact, penetration, etc. to qualify the cylinders. FMVSS 304 goes further requiring 13,000 cycles.

So if the cylinders have seen limited use, i.e., less that two fills a day, seven days and week for fifteen years (do the math), why are they suddenly unsafe at fifteen years and one day?

It all boils down to liability (doesn't it always?). When the lawyers get involved things start to go downhill.

The bottom line is we all need to be safe not sorry. And I recommend sticking to the guidelines, but common sense ought to enter into it somewhere.



afvman/Bill

[jkresse]

Re: New article about tank expiration...

I'm confused! The article talks about allowable tank life being extended to 20, then 25, years. Yet, it then says to follow what's on the label on the tank. My '05 Honda has a 15 year expiration date on it. Why is it not good for 25 years, given that it met (I think) the certification standards that now allow 25 years?

[rtry9a]

Re: New article about tank expiration...

Another big deal... I have a 3600psi system. I can count the number of times Ive gotten a full 3600 psi fillup on one hand over the last 5 years Ive had my cng vehicles. More often than not, its been significantly less than 3000 psi.

[Curtis]

Re: New article about tank expiration...

Tank manufacturers can certify tanks for 15, 20, or 25 years on tanks they manufacture. The 25 year certification is relatively new. The problem is that it is not retroactive to tanks they built that have a lesser terminal life, only new tanks made to that certification.

[larrycng]

Re: New article about tank expiration...

As Bill put it, its about cycling, not just pressure. If you bend a piece of metal enought times, it will break. Using Bill example, for 25 years that would be 16,850 cycles at twice a day. If there is a flaw in the metal, or plastic, we have no idea of when it will break. Put that together with the mentality that I can over pressure a cyinder up to 125% of working pressure (think about the HFA up grades to 3600 without automatically supplying a 3600 psi fill connector that have been mentioned on this site), liability does become a significant factor. Coupled with the change of getting a "good fill" and maybe a little more, we have no idea of when or where a cylinder will cut loose -- so why take the chance. How's your track record with Russian Roulette?

If you put away the money you save for the day you need to buy a new tank to suppport your eco responsible driving habits, you would come close to having it coved. If the vehicle isn't worth keeping on the road, buy everyone on CNG Chat a "Miller"

Larrycng

[ajgiorgi]

Re: New article about tank expiration...

This wouldn't be a big deal if it was cheaper to replace, you know? I think they need to drop the prices of the tanks themselves. I think a grand for the tank and installation is fair, not 2 grand or more. It's ridiculous.

[cowboy]

Re: New article about tank expiration...

This wouldn't be a big deal if it was cheaper to replace, you know? I think they need to drop the prices of the tanks themselves. I think a grand for the tank and installation is fair, not 2 grand or more. It's ridiculous.

cant make any money selling tanks for what they worth so some will keep driving with expired tanks and will kill the innocnent bystander all because no recert so some will keep running junk as they will not resertfiygood tanks and kick bad tanks outjust my thoughts

[Curtis]

Re: New article about tank expiration...

Cowboy, have you been following this conversation? There is now way to recertify the tank without testing it to failure to see if it has a weak point... kind of a one way street for a tank, right? Rather than gripe and complain, spend your money and develop a method of re certifying the tank that isn't destructive to the tank, like X-Ray examination, or some other high tech method that would initially be as expensive as replacing the tank, or more so.

If you look at John's offer, he's saying $2500 installed. That's a tank, brackets (not cheap by themselves), PRD (expensive), and the rest of the components needed to complete the swap. Tanks are never going to be cheap, nor would anything we own, without mass production. You want to help? Get Obama off the liquid fuels kick and mandate CNG like the rest of the countries in the world, only then will tank manufacturer's be busy enough to begin mass production and bring down prices. John is making a fair offer. Other shops may want $2500 for just the tank.

It's amazing how many people bought 1998 & 1999 GX's because they were available and cheap, but failed to factor this situation into the equation. If I buy a house built in 1940... I'm going to factor in re plumbing and maybe even electrical. One must use a degree of intelligence when purchasing any vehicle. I know a lot of folks rushed to CNG in 2008 and then found this site... and then learned that if you buy an old Ford, you may have a compu-valve issue, or the tank on their new Cavalier was due to expire 15 minutes after the purchase. There is an old adage that says "Buyer Beware". Never more true than when taking on something new, regardless of what it may be.

I recognize that people ran to CNG to save money, many because they had to and a cheap NGV seemed like a good solution. Many in the NGV community took advantage of the situation as well. When I was offered $8,000 more for my GX than it was worth, I declined to sell it (but I was tempted). Ask yourself; "just because you can... should you"?

I would only ask members here to either contribute positive information to the group members, like Larry & John and most all of you... or not post anything at all. I can not stand the whining and complaining. Take action to make things better or shut up... please.

I had a number of typo's while writing this reply. Some were a slip of the finger and others were just plain miss-spellings, but my spell checker caught them. I love my spell checker. It makes me look smarter than I am... and, Cowboy, please download a free automatic spell checker off the internet before you post to the site again... and use it. (Google: IE Spell) [See TOS]

[gringostar]

Re: New article about tank expiration...

This wouldn't be a big deal if it was cheaper to replace, you know? I think they need to drop the prices of the tanks themselves. I think a grand for the tank and installation is fair, not 2 grand or more. It's ridiculous.

Good old Supply and Demand at work in America. How many tank manufacturers do you think there are?

[cowboy]

Re: New article about tank expiration...

Cowboy, have you been following this conversation? There is now way to recertify the tank without testing it to failure to see if it has a weak point... kind of a one way street for a tank, right? Rather than gripe and complain, spend your money and develop a method of re certifying the tank that isn't destructive to the tank, like X-Ray examination, or some other high tech method that would initially be as expensive as replacing the tank, or more so.

If you look at John's offer, he's saying $2500 installed. That's a tank, brackets (not cheap by themselves), PRD (expensive), and the rest of the components needed to complete the swap. Tanks are never going to be cheap, nor would anything we own, without mass production. You want to help? Get Obama off the liquid fuels kick and mandate CNG like the rest of the countries in the world, only then will tank manufacturer's be busy enough to begin mass production and bring down prices. John is making a fair offer. Other shops may want $2500 for just the tank.

It's amazing how many people bought 1998 & 1999 GX's because they were available and cheap, but failed to factor this situation into the equation. If I buy a house built in 1940... I'm going to factor in re plumbing and maybe even electrical. One must use a degree of intelligence when purchasing any vehicle. I know a lot of folks rushed to CNG in 2008 and then found this site... and then learned that if you buy an old Ford, you may have a compu-valve issue, or the tank on their new Cavalier was due to expire 15 minutes after the purchase. There is an old adage that says "Buyer Beware". Never more true than when taking on something new, regardless of what it may be.

I recognize that people ran to CNG to save money, many because they had to and a cheap NGV seemed like a good solution. Many in the NGV community took advantage of the situation as well. When I was offered $8,000 more for my GX than it was worth, I declined to sell it (but I was tempted). Ask yourself; "just because you can... should you"?

I would only ask members here to either contribute positive information to the group members, like Larry & John and most all of you... or not post anything at all. I can not stand the whining and complaining. Take action to make things better or shut up... please.

I had a number of typo's while writing this reply. Some were a slip of the finger and others were just plain miss-spellings, but my spell checker caught them. I love my spell checker. It makes me look smarter than I am... and, Cowboy, please download a free automatic spell checker off the internet before you post to the site again... and use it. (Google: IE Spell) [See TOS]

I am sorry if I broke the rules but I will be dammed if I know witch one I see nothing in tos about spelling. and I did not say to keep running old tanks just that some will because of the cost I do like type 1 steel as I pull them and drop them off and get them recertfyed for 25 dollers they are heavy but can be used for years and years I just got a tank of oxgen and the first date is 1957 the last date is 2007 also I cant remember any type 1 tanks blowing up that were in date like the plastic ones sometimes do I do have a few plastic ones but mostley I run steel and buy bigger springs with the small tanks that come in new cars today i dont see why we are using plastic as the weight differance would be only a few hundurd Lbs and could be recertfyed forever till they flunk the weight should only be a problem for big truck with many tanks ie my ford 700 30 tanks about 3.25gge each weight 3850 tanks and brackets I just stay away from scales when loaded as to the spell checker I have one but it will not work when posting here but it will on most other sites so if any one knows why let me know have a great day

[cowboy]

Re: New article about tank expiration...

just thinking it is all about cycling than why not put a counter on the tank that would count the cycles that say a 25% pressure increase as 1cycle and rate the tanks in cycles instead of years me I fill up two to three tims a week my girls car is lucky to get filled 2 times a month as she dont drive it much. than a power co van may fill 2 or even 3 times a day I know there is a reason this cant be done so go ahead and shoot it down I can stand it (ps I may complain but real men dont whine) LOL

[rtry9a]

Re: New article about tank expiration...

I have to ask myself exactly how many cng tanks, tanks that have never been exposed to light or physical damage, have failed in the history of the earth?

[Curtis]

Re: New article about tank expiration...

You're right, the number might be nearly negligible... just wouldn't want to be the one to test how long it takes for an undamaged tank to fail. Are you volunteering? Members like afvman and other members and Mods, who helped write some of the regulations that control the industry today probably have way more insight into the whole subject than we do. I can imagine that it's tough to figure out exactly how to write a rule that, like a blanket, can cover all ngv owners, vehicles and operating conditions & keep them safe without smothering the manufacturers who have to build and price limited production ngv components & vehicles.

Looking at the worst and best case scenario's, one would have to shoot for either the middle, or the worst case scenario. Factor in liability... and you're going to go with the worst case. I like the idea of a cycle counter. I don't know what that would cost, or even if one exists. Does anyone know?