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" Please tell me it's ok to fill expired tanks "

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  • #16
    Re: " Please tell me it's ok to fill expired tanks "

    The first civics will not until 2013. By then, someone will come up with an economical alternative to the dealer prices, and maybe even have a valve that is replaceable.

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    • #17
      Re: " Please tell me it's ok to fill expired tanks "

      I find it very wastefull and unfortunate that such a high cost item such as a composite CNG tank did not have any decommissioning ideas in place when they were created.

      From my knowledge of material science as long as the composite tanks do not suffer physical shock they should last nearly indefinitely but at sequentially lower fill pressures as they age and are cycled.

      We should maybe push the government to mandate all CNG tanks upon expiration can be converted to LPG tanks with a 5 year visual check required, at those pressures the fatigue rate would put the lifespan of the tank itself up to about 800 years. i am certain most LPG users would love a lifetime tank?

      Anyone willing to lobby this? it seems like an extreme waste to toss overpriced composite tanks because of a (as far as I can tell) line in the sand decision that had little to do with material science.

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      • #18
        Re: " Please tell me it's ok to fill expired tanks "

        how expensive would a tank on a 2002 chevy 2500 bi fuel cost?

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        • #19
          Re: " Please tell me it's ok to fill expired tanks "

          Expiration date is there for a reason. Look at the stories out of Pakistan to see why it is a bad idea.

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          • #20
            Re: " Please tell me it's ok to fill expired tanks "

            we could use them for low pressure cng ie 500 psi for just around town. I also buy out date bread at the used bread store and cant remember checking a date on food or a born on date on my beer the greatest scam ever pulled on the beer drinkers of the usa. remember when budwieser had the patented beach wood ageing prosess now we have born on dates they have saved millons not having to store it in a warehouse till it ages just tell folks they dont want old beer and give the born on dates and get rich can you spell SUCKER
            Last edited by cowboy; 01-08-2012, 12:23 AM.

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            • #21
              Re: " Please tell me it's ok to fill expired tanks "

              I looked for info on cng cylinders exploding in Pakistan. Here's what I found:

              "explosions take place more frequently from leaks not cylinder faults."

              "I have seen many terrorist attacks and I have seen cars totally meshed like paper, but CNG cylinder in tact. The suicide blast at Islamabad Marriott Hotel in 2008 ripped the cars parked on the main double road, but not a single cylinder was exploded. It's quite strong thing. Yes leakages can cause huge explosions, as @hash4u said. And also people using non-CNG cylidners for CNG purpose have met accidents/explosions."

              So if you have verified multiple instances of actual CNG cylinder ruptures, please post the links.

              I don't think the current generation of CNG cylinders is in any way dangerous, but I would prefer tanks which were designed to be tested periodically, not just disposed of after 'x' number of years.
              02 GX
              01 GX
              03 Crown Vic
              06 GX
              Home Fueler

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              • #22
                Re: " Please tell me it's ok to fill expired tanks "

                It's fatigue of the material after so many pressure/depressure cycles that limits the life. The consequences of failures are too great and the expense of testing the cylinder to prove that it is still safe have not been deemed to be cost effective. Thankfully, there are not many links to provide where tanks have exploded due to mechanical failure of the cylinder. But if you want to see what an exploding cylinder can do, take a look at the trajectory of the Honda Civic GX tank in the Seattle 2007 incident (just posted in another thread here this AM).
                Craig
                '13 Honda Civic Natural Gas (bright blue!)
                '12 Honda Civic Natural Gas
                '11 bi-fuel Chevy Tahoe
                www.burnusgas.com

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                • #23
                  Re: " Please tell me it's ok to fill expired tanks "

                  Deemed not cost effective by whom? High pressure gas cylinders have been manufactured for decades. Newer style CNG cylinders are the ONLY ones I'm aware of that aren't hydrostatically tested every few years and recertified for service. The dangers of Hydrogen and welding gas cylinder ruptures are at least as great as CNG, yet those cylinders are used and used and used until they don't pass the 'hydro.' I think the decision to manufacture limited life tanks and NOT test them regularly was a terrible blunder on the part of the CNG vehicle engineers of 30 years ago.

                  I wouldn't mind limiting tank life by fill cycles. The current tanks were certified for 15 year service based on 6 fast-fills from empty PER DAY. By that measure my GX tanks should last over 6,000,000 miles. And no credit is given for 'time fills' which are much less stressful on tank walls than 'fast fills.'

                  As far as the Seattle rupture, external fires, especially arson, system leaks, designed pressure relief and accident damage don't count. And they account for all of the CNG 'problems' I am aware of.
                  02 GX
                  01 GX
                  03 Crown Vic
                  06 GX
                  Home Fueler

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                  • #24
                    Re: " Please tell me it's ok to fill expired tanks "

                    Well said freedml.
                    Adrian

                    Navy 2008 Civic GX (wife's)
                    Silver 2012 Toyota Prius
                    Grey 2012 Civic Natural Gas (mine)

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                    • #25
                      Re: " Please tell me it's ok to fill expired tanks "

                      I would like to know the Seattle vehicle was up to date on inspections and maintenance since it is a government vehicle (XMT plate). I would also like to see the failure report.

                      The reason we went to visual inspection was to get away form hydrostatic tests which ment removing the tank from the vehicle, taking it to a testing facility, etc. How many days is the (your) vehicle out of service every 5 years (which used to be the standard)? Oh and doesn't Honda say that if the tank is removed from the vehicle or from the "rack" it can not be reinstalled in the vehicle? Curtis??

                      We could take some of these 15 year old tanks for hydrostatic and or burst testing. If a significant percentage of a specific percentage of a manufacturer's tanks pass give that model of tank a five year extension and do it again.

                      I'll stay with visual inspection

                      Larrycng

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                      • #26
                        Re: " Please tell me it's ok to fill expired tanks "

                        I am still driving a '92 bi-fuel truck with expired tanks...use it as a commuter every day, I think the tanks expired in 2007...Safety inspections over the years never asked once about my tanks. From all the posts here, I'm just now beginning to realize I probably shouldn't keep chancing it. BUT, for those out there who ask if tanks will work after they expire, mine have. I'm not advocating anything, just sayin'...

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                        • #27
                          Re: " Please tell me it's ok to fill expired tanks "

                          Originally posted by bergtsam View Post
                          I am still driving a '92 bi-fuel truck with expired tanks...use it as a commuter every day, I think the tanks expired in 2007...Safety inspections over the years never asked once about my tanks. From all the posts here, I'm just now beginning to realize I probably shouldn't keep chancing it. BUT, for those out there who ask if tanks will work after they expire, mine have. I'm not advocating anything, just sayin'...
                          Remind me to not pull up next to you at a fueling station... I want to live to see another day.
                          Jared.
                          Mountain Green, Utah
                          2003 CNG Cavalier
                          2003 CNG Silverado 2500HD

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                          • #28
                            Re: " Please tell me it's ok to fill expired tanks "

                            Its just like "Russian Roulette" Sometimes you win and sometimes you lose

                            Larrycng

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