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View Full Version : What do I do when my tanks EXPIRE!



fquinonez
11-01-2008, 03:56 PM
Thre was a thread a few months back regarding what to do with an expired tank. I would like to take this conversation a step further. What can we do with a car that has expired tanks? There are many used "fleet" vehicles that have been resold into the consumer market. I, myself, own 2 of these vehicles. As the vehicle (and the tanks in them) age, what can be done to keep the vehicles on the road after tank expiration?

What are the options and the costs?

Frank Q.

Lakewood90712
11-01-2008, 04:17 PM
Options ?

1. Retire the vehicle, part it out , or If bi-fuel , it's gasoline time again.:(

2. New tanks. Could run as little as $ 3,500 to as much as $10,000 - each .:eek:

3. Used tanks in date . Cost $500 and up.

The tank certification process is QC of the production lot, inspections of all ,and distructive testing some of the lot. If any fail the destructive test, the whole lot is failed and scrapped.

No known way to re-certify.

Amfuel
11-01-2008, 05:38 PM
And be prepared to replace them when you go in for the inspection. If they are expired the technician is supposed to render them unusable. (drill holes in them) The inspector should warn you though.

CNGCARS
11-02-2008, 07:33 PM
Frank,

I am a CSA certified CNG Cylinder inspector and can inspect the cylinders for you if needed. In early 2009 we will be offering services to add or replace CNG Cylinders. Let us know if & when you need us, mean while check out our website below.


Mario
CNG CARS
AAA CNG Systems
www.CNGCARS.la

larrycng
11-02-2008, 09:34 PM
And be prepared to replace them when you go in for the inspection. If they are expired the technician is supposed to render them unusable. (drill holes in them) The inspector should warn you though.

Hate to say it, but you are incorrect.

The job of the inspector is to inspect the cylinders. As part of inspection, the inspector must remove guards and/or shields (and replace them when the inspection is completed), unless the owner of the vehicle wants to remove and replace the himself. The inspector should also clean the cylinders with gentle soap and water so that he may see any damage. The owner could also do this to save a little money. I charge by how much I have to do to inspect the cylinder.

The Inspector DOES NOT HAVE THE AUTHORITY under the terms of his certification to render the cylinder "un-useable". The cylinders belong to the owner of the vehicle. Unless the owner of the vehicle authorizes the inspector to render the cylinders un-useable, the inspector MAY NOT DO SO (CGA C-6.4 section 9.

There is nothing in NFPA -52 or CGA C-6.4 giving the inspector the authority to render the cylinders un useable in the event the cylinders have damage classified as Level 3 -- and out of date is considered level 3 damage,

If the inspector indentifies the cylinder as having level 3 damage, He is suppose to affix a cylinder inspection fail label to the cylinder indicating the cylinder is unsafe and should be distroyed, noting the condition that determined level 3 damage on the inspection form, and have the owner of the vehicle sign the inspection form. The owner of the vehicle should be given a copy of the completed and signed inspection form and inspector keeps a copy. Under CGA C-6.4 section 7.12.3, the owner is entitled to second opinon.

This is a little long and detailed. but I wanted to cover the bases and make sure there is no question. If there is a local ordinance giving the inspector the authority to render the cylinders unuseable, please let me know, and I will appreciate it and stand corrected. Local authorities having jurisdiction (AHJ's) can make any rules or regulations they want

I hope this helps

Larrycng

P.S. Please defuel the cylinder before drilling any holes in it.

John Mitton
11-03-2008, 09:36 AM
Anyone know of state or local laws allowing an inspector to drill holes in the cylinder without the owner's permission?

Highmarker
11-03-2008, 10:07 AM
As far as the Cavalier is concerned. I check with a Chevy Dealer in Utah and he said that he could order new tanks from GM for the Cavalier. It would take 3 days to get it and would cost $3000. Pressed steel made the tanks for the Cavalier. Everything I have heard about them is they are no longer in business, although they still have a website. GM might have some tanks in a warehouse somewhere, but the expiration date on the tanks are set at the date of manufacturing, not the date of installation, so those tanks in stock are soon to expire as well.

fquinonez
11-09-2008, 03:18 AM
Thanks for all of the ideas and replies. I still have about 3 years before my first vehicle runs out of time, but I find it amazing that a replacement tank can cost from $500 to $10,000 according to the posts. Unless something is done about issues like this, I can definately see a limit to the acceptance of CNG as an alternative motor vehicle fuel in the general populace.

If we have anyone on these forums with a foot in industry or government, this is why we need EPA and CARB to make sure we have certification programs that work and don't discourage companies from producing new and replacement CNG parts in the United States.

Luke
11-09-2008, 12:32 PM
The bi-fuel service manual supplement I have on my 2002 Express Van states (6-179: Fuel Tank Inspection):

"Any tank in service for fifteen years or more must be removed from service using the following procedure:
1. Remove the tank . . .
2. Vent the tank . . .
3. Disconnect vent hose
4. Allow tank to stand for 24 hours . . . [with valve open]
5. Place tank outside in ventilated area
6. Drill 1/4-in hole after the last digit in the tank identification number at the valve end of the tank.
7. Dispose of tank in safe & approved manner."

TheBundo
11-10-2008, 03:28 AM
Frank,

I am a CSA certified CNG Cylinder inspector and can inspect the cylinders for you if needed. In early 2009 we will be offering services to add or replace CNG Cylinders. Let us know if & when you need us, mean while check out our website below.


Mario
CNG CARS
AAA CNG Systems
www.CNGCARS.la

Why does your website, on the following page, say "Comes with a HUGE Factory 11.4 gge CNG Tank that is equivalent to 35.7 US Gallons"? gge means Gasoline Gallon Equivalent, yet you are trying to say it's 3 times that much.

http://www.cngcars.la/inventory.html

Steve
11-10-2008, 09:22 AM
I'd place my bets that there is the GGE equivalent energy storage for CNG and then there is the actual volume of the tank. Probably a bit confusing as it is advertised.

gastronaut
10-12-2009, 05:04 AM
For those who plan to remove their CNG tanks from service, one trick to assure the vessel is completely purged is to fill it with water befor drilling the hole. Remember that a concentration of 5-15% natural gas with air is combustible.

Also, it wouldn't hurt to drill a few holes, destroy the threads at the neck or cut the cylinder in two. I just now at some point someone will try to patch a 1/4" hole on a condemned cylinder and continue using it. Do what you must to be assured it will never be used again.

Good luck.

larrycng
10-12-2009, 07:38 PM
Well, it is suppose to be a 1/2 inch hole according to CGA C 6.4. Another trick is to take out the valve and use hack saw to cut the tank in half starting with the valve port -- you only to go deep enough to go through the threads in the port -- slice in like a hot dog. Use some WD 40 or oils to keep the saw lubricated and prevent sparks on steel or steel lined tanks

Larrycng

Franz
10-12-2009, 08:06 PM
If the valve is removed a pretty good sized hammer blow will ruin the threads. I saw a tank where someone had actually threaded the 1/2" hole and installed a pipe plug!

Go figger.

Franz

larrycng
10-12-2009, 10:59 PM
Well Franz, someone once told me to never to underestimate the power of human stupidity

Larrycng

gaspig53
11-16-2009, 12:27 PM
Have a 2002 Civic NGV with a extra tank that has no expiration sticker on it.
Can this tank be inspected and certified? If not do I just disconnect it or do I have to remove it?

Highmarker
11-16-2009, 01:12 PM
Have a 2002 Civic NGV with a extra tank that has no expiration sticker on it.
Can this tank be inspected and certified? If not do I just disconnect it or do I have to remove it?

gaspig53,

There are couple of things to do first.

1) Check the entire surface of the tank. Sometimes the label is located on the underside of the tank (out of plane view). Use a mirror if needed.

2) If no "expiration" label is present, but a "manufacturer" label is, contact the manufacturer for a replacement label. Unfortunately, if the manufacturer is out of business, then you are out of luck. With no label and no way to replace the label, you must remove the tank from the vehicle.

Franz
11-18-2009, 05:49 AM
One issue that popped up a couple of years ago is that there is no plan for disposing type 3 or type 4 cylinders. They are not typically recyclable, and the cost to recover the materials for any recycling attempts greatly exceeds the cost of a new cylinder.

Landfills anyone?

larrycng
11-18-2009, 10:11 AM
A " sawsall" works great on a type 4. Small pieces are easy to dispose of -- even in the home garbage -- a little at a time. You might want to a dust mask when doing the job.

I've cut up a type 3 with a sawsall for training aids. It takes a takes several blades.

Type 3 cylinders, when cut length-wise make good watering and feed troughs
for live stock

A storage tank for your home air compressor???? Safety factor of about 200 +

You could always donate the cylinders to a school that has an alt fuels program

later

Steverinomeister
09-15-2010, 10:24 PM
I've bought a very nice 96 CNG Crown Vic with 26,000 miles on it from a local government. The tanks expire at the end of this year. There are no public CNG stations in my area so I am planning on converting to conventional gas, I already have all the parts to do this. My problem is, the government kindly filled the tanks at the time of sale, so I have four full cylinders of 3000 psi highly flamable gas. My question is, can I just drive this car 'till the engine quits and will that render all four tanks to 0 or atmospheric psi, then can I safely pull them off?

larrycng
09-15-2010, 11:05 PM
I would drive the vehicle until it gets down to a quarter tank on the fuel gauge then have the remaining gas vented in the proper and safe manner. The tanks will then be safe to remove. The tanks are probably PST (Press Steel Tanks) and are heavy. The ones outside are the easiest to remove. The inside tanks are a bit more difficult. Check the file on this web site, there is a copy of the Crown Vic CNG publication that will give you an idea of how the thing is put together. It is best to have a professional do it.

Why not run the vehicle until about a month until the tanks expire? In the mean while look around for some newer tanks and have them installed.

It sounds like you got a nice car. Converting it to gasoline will cost some big bucks (gas tank, fuel lines, injectors, necessary changes to the wiring, replacement of the EEC V computer and probably re-programing). Then you may have to run premium fuel because of the 10:1 compression.

Hope this helps

Larrycng

Steverinomeister
09-15-2010, 11:58 PM
Thank you Larrycng for the detailed information. I would really like to have a pro take these cylinders out. I live in the Portland Oregon area, could you point me to someone in this area?
Thank you
Steve

cowboy
09-16-2010, 07:17 AM
could he put a propane tank in and a vaperiser and tie in to the low pressure line and run it on propane as there is no cng where he is and then the high compression would not be a problem and it would still be a clean air car or would the higher btu be a problem or would the o2 and the computer pick up the differance and ajust the mix? just my thoughts

larrycng
09-16-2010, 09:40 AM
I have a couple of ideas on tank removal. I'm looking for some phone numbers, give me a PM and I will give you the names and numbers.

As for Cowboy's comment, that is a possibility. The compression would be ideal for LP and the O2 would be no problem. The injector flow rate would probably be too high and throw off the fuel trim numbers. and possible tripping the check engine light giving you problem with DEQ. Also the pressure sensors would have to be tweeked since the gaseous LP would be at lower pressures which would drive the injector pw higher and again would throw a check engine light because of fuel trim and low pressure. It would be an interesting project and you wouldn't have to do much with the wiring.

Larrycng

cowboy
09-20-2010, 07:38 PM
I have been thinking again so get feared why cant the expired tanks be checked for damage and re rated for say 2000 psi and change the filler this should give a good margin of safety and say 5 or ten more years and move the car to local use say for moma to go to the store or you to the parts store kinda like when we were kids moma got dads old car

mbalce
09-20-2010, 11:22 PM
Interesting idea, but where would you get a 2000 psi fill? I only see 3000/3600 options. Now, not meaning to open an old can of worms, and i read through a lot of old threads on the subject even on this board, but what I still don't get is that my understanding is the most stress and wear comes from the fill/empty cycle and that 15 years was a bit arbitrary. If that is the case, how do taxis run these things for over half a million miles with no incident? I have heard that some of the Super Shuttles went over a million miles.

cowboy
09-21-2010, 10:08 AM
good question on the fill. how about we install a regulater that is set at 2000 lbs in the fill line of the car and not change the fill fiting than one could fill at 3000 or 3600 but only get a 2000 fill to the tanks and we could do this to the 3000 cars also and than they could fill at 3600 pump or could we come up with a onboard temp compensater that could be set for the 2000 or 3000 limit?

cngacrossusa
09-23-2010, 08:33 AM
Hey Steverinomeister of Portland, OR . . . . I'd sure recommend getting your own Fuelmaker rather than wasting money tearing down a perfectly good working dedicated cng vehicle!! Further, with the massive trunk of the Crown Vic, you could easily put some other current cng tank in there. Watch CL listings for a tank bargain, and ask a guru here on cngchat where to get closest tech to swap out the cng tank. CNG folks in Utah find ways to get new cng tanks as well.

Best case scenario, I'm guessing a used tank could be found for $500 to $750 in the 9 gge size range, and add another $500 for installation and your dedicated Crown Vic with only 26,000 miles is good to go for another 300,000 or 400,000 miles!!! Buy yourself a used C3 for FM4 Fuelmaker for $2,500 to $4,000 and you've got a commuter car for the rest of your lifetime!!! Sure beats throwing away money on a stinking Prius!!

Worst case scenario, just sell it to cng supporter who will do what it takes to save the car if you won't . . . . do Not tear it down, that'd be such a waste.

Steven86
09-24-2010, 01:02 PM
What is the average life span of these tanks? Do they expire 1 year, 2 years, 5 years, or longer?

cngacrossusa
09-24-2010, 03:22 PM
Tanks typically had 15-year lives stamped on their labels . . . thus a 98 Civic GX or bi-Fuel Ford pickup would have tank with expiration dates printed on the tank label saying like Expires Sept 2013. Older cng vehicles like Dodge vans from early 90's (let's say a 1992 Dodge) would have tank label saying Expires Oct 2007.

FYI to Steven86 in Houston . . . there are also different "Types" of tanks ranging from Type 1 (steel) to Type 4 (full composite). Many old school cng guys feel that Type 1 steel tanks (when installed and taken care of properly) likely could have much longer life than stated 15 years . . . . reason being is that DOT bottles (typically 6 gge) that are used for storage in some public cng stations (ie bunch of bottles daisy-chained together) can have lives longer than 15 years if they are inspected and repainted to gain an additional 5 years at a time.

However, recent tank manufacturing techniques are getting better and better and now vehicle installed tanks generally have 20-year life stamped on the tank label for all types (1 through 4).

Steven86
09-24-2010, 03:47 PM
Tanks typically had 15-year lives stamped on their labels . . . thus a 98 Civic GX or bi-Fuel Ford pickup would have tank with expiration dates printed on the tank label saying like Expires Sept 2013. Older cng vehicles like Dodge vans from early 90's (let's say a 1992 Dodge) would have tank label saying Expires Oct 2007.

FYI to Steven86 in Houston . . . there are also different "Types" of tanks ranging from Type 1 (steel) to Type 4 (full composite). Many old school cng guys feel that Type 1 steel tanks (when installed and taken care of properly) likely could have much longer life than stated 15 years . . . . reason being is that DOT bottles (typically 6 gge) that are used for storage in some public cng stations (ie bunch of bottles daisy-chained together) can have lives longer than 15 years if they are inspected and repainted to gain an additional 5 years at a time.

However, recent tank manufacturing techniques are getting better and better and now vehicle installed tanks generally have 20-year life stamped on the tank label for all types (1 through 4).

Thanks for the info!

Franz
10-05-2010, 08:32 AM
One of the primary issues with cylinder life is exposure to liability by the cylinder manufacturer. In many cases, the cylinders have not changed appreciably in design but their insurer underwriter bacame more willing to accept a longer life/greater risk due to the increasing number of cylinders on the market. This is why many newer cylinders have an increased life rating. As for the steel type 1 cylinder, it has not changed since the 80's, yet they are rated for 3600 psig and a longer life than the late 80's 2400 psig 5 year life with hydrostatic pressure testing. The cylinder manufacturer underwriter has been willing to accept the longer life even though there are no appreciable changes in the cylinder design since there have been relatively no problems with the design.

Any modification to the original tank design by the cylinder manufacturer by extending the life by lowering the pressure or just keeping the cylinder in service after the expiration date would leave absolutely no support by the manufactuerer and the vehicle/cylinder owner would bear ALL liability IF there were an accident of any type, even if not related to the cylinder.

One case I was involved as an expert witness, the plantiff's counsel demonstrated that the defendant showed a disregard for safety by circumventing a manufacturer designed safety system (he had defeated the antilock brake system by hydraulically bypassing the control unit). The case did not involve the brakes, but the plantiff's counsel was able to successfully shift the focus to the defendants history. In court, its called "Exploration", where by a through a series of related investigations, other issues are uncovered which may have some effect on the outcome of the case.

In the case of CNG cylinders, any attempt to circumvent the manufacturers rating would likely shift the focus directly to the owner even outside of the cylinder issue.

michael714
12-02-2010, 09:15 PM
Sorry for reviving this dead thread, but...

I have a 1996 Ford F-250 Bi-Fuel and the fuel door says that the tanks expire in May 2011. Other than that, the truck is fine. There's no certified CNG inspectors or mechanics within 60 miles of me and even if there was, it seems the cost of new tanks is just too much for me. So, here are my questions:

If I just run the engine using CNG until the tanks are "empty," can I just forget about the CNG and run the truck on unleaded til it dies? Or, is there some special procedure necessary to depressure the expired tanks?

Any thoughts would be appreciated,
Michael

larrycng
12-02-2010, 10:50 PM
Yes Michael you can run on gasoline until it dies. You're on the right track about running the tanks down on CNG until the engine dies. Yes, there is a procedures for venting the tanks to zero pressure and should be done by a trained individual. When the tanks expireCGA C-6.4 requires that the tanks have at one 1/2 hole drilled into the tank (after it is vented to zero pressure). I would suggest removing the tanks; why carry the weight?

Hope this helps

Larrycng

Highmarker
12-03-2010, 08:50 AM
When the tanks expireCGA C-6.4 requires that the tanks have at one 1/2 hole drilled into the tank (after it is vented to zero pressure).
Larrycng

Don't forget to purge the tanks before you drill the 1/2" hole. Do not purge the tank with air, use water. Fill and drain it several times with water. Usually what I do is drill two 1/2" holes so that they overlap each other and make kind of a figure eight that way this is not chance at all of someone finding the tank and putting a pipe plug in it and trying to re-use it.

ericguy320
12-03-2010, 04:39 PM
And use a air drill, not electric!

cowboy
12-03-2010, 07:31 PM
if you just fill all the way with water there can be no gas left and just drill it with a air drill so you dont get the shock of your life when the water runs out

Lotta gue
03-27-2011, 11:49 AM
I have been an oxygen acetylene dealer for many years and think CNG it the future. Being in the state of Missouri there are no CNG filling stations, It seems the tanks are the biggest cost and there are allot of expired ones out there so anyway I was speaking to my gas supplier about tanks and he told me they would could recertify them. Am I missing something??

bruin
03-27-2011, 06:05 PM
From what I know of the ridiculous DOT and EPA regualtions surrounding this issue... the only way the tanks might be legitimately re-certified is if the manufacturers were willing to make the effort. Obviously, none of the manufacturers have any sort of vested intereset in doing so when they can simply sell new tanks.