All about tanks

[Aaragorn]

I hope the people who know will make this thread useful for everyone who wants to learn about cng tanks. It is a real pain trying to learn all the abbreviations and stuff, convert the sizes and dimensions and measuring units. All to try to figure out how big or how much weight it will add, pressures...it's a nightmare.

Please help me sort it all out.

First question.

Can we get a list of tank manufacturers in the usa? are there any? Who makes cng tanks and what are their contact info/websites? When I google all I come up with are websites in foreign languages.

Second question.

How do we identify standard sizes? are there standard sizes? is it better to have long and small diameter or shorter and larger diameter? What are the standard sizes?

[jetboatjohnny]

Re: All about tanks

Search the forum, there is a thread with a few links to pdf files with tank specs from a few manufacturers.

[cngmike]

Re: All about tanks

Search my name I posted a links to all of the tank mfg. sizing charts. No manufacture sells directly to the public.

[jblue]

Re: All about tanks

Search my name I posted a links to all of the tank mfg. sizing charts.

I thought I would share since I already did the work to find the thread.

http://www.cngchat.com/forum/showpost.php?p=4980&postcount=5

[freedml]

Re: All about tanks

I had a smog check the other day and they have 13 adapters to test gasoline caps. Likewise, every car seems to have a different CNG tank design.

[afvman]

Re: All about tanks

allgone(sp?)

One of the best resources for technical info is the Clean Vehicle Education Foundation (CVEF), formerly the NGVC.

The link to CNG cylinder information is:

http://www.cleanvehicle.org/technology/cylinder.shtml

There's also good information at the NGVAmerica website:

http://www.ngvc.org/tech_data/tech_bull.html

where you'll find the latest Technical Bulletins re. CNG cylinders.

Also check the 'Tools and Resources' tab and the 'Technology' tab.

Good luck,

afvman/Bill

[Aaragorn]

Re: All about tanks

here's a question about tank expirations and tank failure...

tanks expire because apparently they flex and expand and contract and eventually fatigue will thru continued use cause them to fail.

but my question is how much danger is there in a tank failure from extended use? It seems to me that an extended use failure would not be an explosion but it would eventually produce a leak which would depressurize the tank. The venting gas could be ignited but that itself wouldn't represent an explosion but a jet plume like flame which would only actually burn on the outer end of the plume where the gas mixed sufficiently with the air to make a combustible mixture. I'm told that pure cng itself isn't combustible and is only combustible when diluted with enough air to allow combustion. Hence this jet plume would gradually diminish until it would finally exhaust to a small flame with little pressure and go out. That is only assuming that it would ignite and that it seems to me is the only danger it represents to tank failure...

what I conclude is that a tank stored out of doors and away from any kind of ignition flame would simply vent without ever igniting if the tank failed, This would basically not be a danger would it?

Let's say for example that someone had a tank stored on a trailer which they would use to heat their cabin. Periodically they would tow the trailer down to a filling station and fill up and then tow the tank/trailer back up to their cabin. They would park the trailer outside their cabin and hook it up. If this tank failed because it was used too long wouldn't it simply vent harmlessly?

[cnghal]

Re: All about tanks

Aaragorn,
Here's an idea, go get a Ouija Board, hold a seance and ask the Supershuttle driver that died, when his tank failed if it just "harmlessly vented it's contents" before it threw him 40 feet to his death.

Or you obviously haven't seen the pictures of the flattened Honda from Washington State that launch it's tank 100 feet away when it's PRD failed to "harmlessly vent off it's contents".

Besides, it's not legal to use NGV 2 cylinders on a trailer. You would use DOT 3AAA bottles that are hydrostatic tested and recertified every 5 years.

[Mshepcomm]

Re: All about tanks


IMHO...

I don't know about the Washington Honda incident, but regarding the Super Shuttle explosion in Carson, you don't need a OUIJA board to know that when you have a CNG van with tanks under the back of the vehicle "rearended" in a traffic accident and do not have the tanks inspected before it leaves the body shop, you are asking for trouble.

If you are in a car accident with your CNG vehicle, and are in too big of a hurry, or ??? and don't get the tanks inspected (and demand that the insurance company fixing your car pay to have them inspected), aren't you just asking for trouble, and a Darwin Award?

I really feel for the Super Shuttle driver's family, but I can't help thinking that his death could have been easily prevented.

[cnghal]

Re: All about tanks

Thanks Austin,
Another note unrelated to tanks, but curtainly relevant to the pressure.
When servicing a CNG system, always assume it is pressurized.
Always wear eye and ear protection. The first time you crack an improperly made fitting, write us to let us know how it went. You should still be able to type with at least one finger even though you won't be able to hear the clicking of the keys.
Also, don't assume the "low pressure" side of the regulator is safe. Many OEMs and kit manufacturers use 90-150psi at the fuel rail. Crack a quick disconnect under pressure and you will see just how much compressor oil is making it into you engine, you will be wearing it. On a positive note, your hearing will most likely return after a few hours.

[jblue]

Re: All about tanks

Compare that to 3600 PSI, and it's mind boggling!

I forget where I read it, but something was said about the force exerted being in the millions of pounds.

(after five minutes of searching)

I found it!

http://www.cngchat.com/forum/showthread.php?t=1747

[cnghal]

Re: All about tanks

Wow, that's interesting. Now lets do the math on a hydrogen tank at 10,000psi

[Highmarker]

Re: All about tanks

Please see my other post about CNG tanks.

http://www.cngchat.com/forum/showthread.php?t=1747

These tanks are NOT to be underestimated nor compromised. Can you imagine what the media would do if there was a CNG tank explosion on I-15 in downtown Salt Lake City. The following are real life examples:

Carson, CA: Supershuttle van explodes during CNG filling - The media did not mention the fact that the van was in a rear-end accident the week before and just got out of the body shop and the owner of the van did NOT have the tank inspected prior to filling it (It states this on the label on the CNG tank).

Seattle, WA: Honda Civic GX explosion - The media did not mention the fact that this explosion was a result of arson.

If you were to use a tank that was past expiration and it exploded or leaked causing an accident. I'm sure the media would NOT mention the fact that you were using an expired tank. They would go off on how DANGEROUS these tanks/vehciles are. It would hurt the CNG movement more than you can imagine.

Please do NOT treat these tanks as if they are normal gasoline tanks!

[Aaragorn]

Re: All about tanks

ok, I guess you all cleared up that misconception for me. Thanks.

[Aaragorn]

Re: All about tanks

Aaragorn,
Here's an idea, go get a Ouija Board, hold a seance and ask the Supershuttle driver that died, when his tank failed if it just "harmlessly vented it's contents" before it threw him 40 feet to his death.

Or you obviously haven't seen the pictures of the flattened Honda from Washington State that launch it's tank 100 feet away when it's PRD failed to "harmlessly vent off it's contents".

Besides, it's not legal to use NGV 2 cylinders on a trailer. You would use DOT 3AAA bottles that are hydrostatic tested and recertified every 5 years.

Dude, please don't get angry at me for asking the question. Would you prefer I not ask? No I havn't seen the pictures. What is a PRD? I don't come here as a expert on this stuff I come here as someone asking questions so I can learn. A little less hostility for us simple learners please.