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Class A propane tank refills


chindog

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Can you elaborate on this? I have filled many 100 pound bottles that were completely empty with no problem.

You mean they have no pressure above atmospheric. If completely empty you would have a vacuum in the tank. When at 0 gauge you can get air rushing in, which you don't want.

Barb & Dave O'Keeffe
2002 Alpine 36 MDDS (Figment II), 2018 Ford C-Max HYBRID
Blog: http://www.barbanddave.net
SPK# 90761 FMCA #F337834

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Can you elaborate on this? I have filled many 100 pound bottles that were completely empty with no problem.

 

You mean they should no pressure above atmospheric. If completely empty you would have a vacuum in the tank. When at 0 gauge you can get air rushing in, which you don't want.

Exactly.The fact is that many a fill station may not appear to pay much attention, but if they are observing the safety rules, they do note a totally empty bottle that is at atmospheric, or 0#. When your furnace or gas appliance fails to burn, that does not mean that the tank is completely devoid of propane, but only that the rate of liquid to gas state has fallen so low that it can't supply enough to keep things working, yet it is not totally empty and it remains above atmospheric pressure. A supplier who fills a bottle that has fallen to atmospheric pressure will be in serious trouble should he be caught by code enforcement.

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

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I disagree, when we fill new portable LP bottles they actually have negative pressure in them shipped from the factory. There is nothing required to report a 0# bottle and if there is, who do we report it to and what form do we use? As far as air in the tanks or system it gets bled out as soon as you turn your stove on. That's why it takes a couple of minutes to light the stove after a tank change.

This posting has discussed 2 different systems being residential and portable and both systems have different rules applied to them.

Greg

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I understand the theory of the 1/2 tank taking longer to heat up in a fire but in the big picture I am not going to worry about it. Can you imagine this. Honey, yes I know it is going to be 20 degrees tonight but we have to turn the heat off because the tank is down to 1/2 because it would be safer in case we have a fire.

Well?

Bill

2008 Newmar Mountain Aire model 4521
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Towing a 2014 Honda CRV with a blue Ox tow bar

Home base Fort Worth Texas

A man who carries a cat by the tail learns something he can learn in no other way.

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I disagree, when we fill new portable LP bottles they actually have negative pressure in them shipped from the factory. There is nothing required to report a 0# bottle and if there is, who do we report it to and what form do we use? As far as air in the tanks or system it gets bled out as soon as you turn your stove on. That's why it takes a couple of minutes to light the stove after a tank change.

This posting has discussed 2 different systems being residential and portable and both systems have different rules applied to them.

Greg

I'll add that "negative pressure" means it has already been purged at the factory, for those who didn't understand that.

 

2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country.  John F. Kennedy 20 Jan 1961

 

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The negative pressure from the new tank factory I believe is to reduce condensation from forming and subsequent rusting in a new tank. A LP system does not need to be purged like a refrigeration system does. Air doesn't hurt or react with propane, the propane will just boil off and disperse at atmospheric pressure. When you fill a LP tank that has air in it, it just forms a air bubble on top of the filled tank. When you go to use the tank the air gets released first which is why the stove won't light right away. Once the air is gone, then the gas vapor starts to exit and now the stove can be lit.

Greg

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In a crash scenario, it is a near empty propane tank that is the worry. Remember, liquid doesn't burn, only vapor burns. So a full tank rupturing, is less explosive than a 1/2 tank. Partially filled tanks means that the spark from metal on metal during the crash can ignite and you have the potential for a BLEVE - Boiling Liquid Expanding Vapor Explosion. All kinds of really interesting calculations can be made on different scenarios with different petroleum products.

 

Barb

Barb & Dave O'Keeffe
2002 Alpine 36 MDDS (Figment II), 2018 Ford C-Max HYBRID
Blog: http://www.barbanddave.net
SPK# 90761 FMCA #F337834

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Sorry Barb, but if a propane tank ruptures with a full tank or any liquid propane in it, it will vaporize as soon as it is exposed to atmospheric pressure and any spark will create a huge fire ball. Liquid propane can't exist at atmospheric pressure above -43 F like gasoline does, it will turn to vapor gas immediately.

Greg

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You missed the point, yes the liquid will vaporized, but if the tank is FULL, you don't have the vapor already sitting there waiting for the spark that will ignite it.

 

Greg - I have a Masters degree in Chem Eng. Spent a lot of time doing EHS work and the worst rail explosions are not from FULL propane cars (or other volatiles), they are from those only partially full (or empty) where the tank is full of vapor. It is the initial spark on shearing that get is going. If full, it is possible to have rupture and leakage but no fire. Just like a match can be dropped into a full container of gasoline and go out, while a match held over an 'empty' tank on the lawnmower will burst into flame - presence of vapor.

 

Just like someone putting the tongs on a forklift through the sides of a 55 gallon drum - - if only partially full or 'empty', it can result in a bad explosion, if full, you get a leak but no fire if you can shut off all ignition sources quickly. One of the reasons that definition of Flammable was raised to 140°F because we have loads of places where working conditions in the summer are over 100°F.

Barb & Dave O'Keeffe
2002 Alpine 36 MDDS (Figment II), 2018 Ford C-Max HYBRID
Blog: http://www.barbanddave.net
SPK# 90761 FMCA #F337834

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The negative pressure from the new tank factory I believe is to reduce condensation from forming and subsequent rusting in a new tank. A LP system does not need to be purged like a refrigeration system does. Air doesn't hurt or react with propane, the propane will just boil off and disperse at atmospheric pressure. When you fill a LP tank that has air in it, it just forms a air bubble on top of the filled tank. When you go to use the tank the air gets released first which is why the stove won't light right away. Once the air is gone, then the gas vapor starts to exit and now the stove can be lit.

Greg

You are partially right. Purging is the action required to remove all moisture-laden air from an LP tank. I know you've read about someones LP regulator freezing up in cold weather and they have no gas flow. That is a sure sign their tank should be purged (pull a vacuum in the tank) to remove the moisture inside.

Liquid LP does not vaporize immediately. I have poured liquid LP into a paper cup(demonstration) at seminars on Propane, it simply boils away until the cup is empty, it is not immediate total vaporization-vaporization only occurs on the surface, it takes perhaps 3 minutes for that paper cup to become empty. Barb is correct.

All this has little to do with the thread topic anyway.

 

2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country.  John F. Kennedy 20 Jan 1961

 

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.... Remember, liquid doesn't burn, only vapor burns. ...

Not true. 'Burn' is the most common term for the chemical reaction of combining with oxygen. Some vapors, liquids and solids will burn; some won't. Steel will burn quite nicely, particularly when under water - then resulting ash is called 'rust'. Aluminum burns nearly instantly when exposed to air. The aluminum oxide formed doesn't burn, so the reaction quickly stops. Unless you rub it and get the aluminum oxide 'rust' black stuff on your fingers and more is immediately formed so if you keep rubbing you will keep getting more and more black stuff. That's why they anodize some aluminum things so they are protected from air and won't make your fingers dirty.

 

Of course this really doesn't have much to do with the original topic, I just didn't want to leave the impression that liquids won't burn go unchallenged, as it might have bad consequences.

F-250 SCREW 4X4 Gas, 5th NuWa Premier 35FKTG, Full Time, Engineer Ret.

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Fire is the rapid oxidation of material resulting it the release of heat and light. Barb is correct in the statements relative to the scenario; technically, burn is a very subjective description of what happens.

Legendsk, in order for your statement to be relative, you should define what is a "liquid" vs solid.

 

On second thought, forget it this is getting too deep, and immaterial to the topic.

 

2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country.  John F. Kennedy 20 Jan 1961

 

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I had made a note to not let the propane tank get below half full. Now it is several months later, I can't remember why the tank should not get below half full.

You missed the point, yes the liquid will vaporized, but if the tank is FULL, you don't have the vapor already sitting there waiting for the spark that will ignite it.

As the one in this thread who probably has the largest knowledge base to use in drawing a conclusion, how much credence would you give to the comment about a half tank of propane and do you keep yours at or above half full at all times when traveling?

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

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We don't keep ours filled up when traveling. I was just giving information about why a full tank is better than a 1/2 tank in terms of a crash that punctures the tank. I think that a lot of the information given at fire seminars are based upon what firemen learn in their training and one of the worries about train derailments has always been whether tanker cars are full/half-full/empty and what that can mean in an accident. I did a lot of training sessions with people involved in transportation of hazardous material. One of the planning scenarios for a lot of first responders would involve a large propane delivery truck, 1/2 full, on a freeway overpass interchange.

 

Barb

Barb & Dave O'Keeffe
2002 Alpine 36 MDDS (Figment II), 2018 Ford C-Max HYBRID
Blog: http://www.barbanddave.net
SPK# 90761 FMCA #F337834

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I think that a lot of the information given at fire seminars are based upon what firemen learn in their training and one of the worries about train derailments has always been whether tanker cars are full/half-full/empty and what that can mean in an accident.

Thank you Barb, for your comments. I'd add that even professional firefighters and fire trainers do not all agree in every case. I have a brother-in-law who is a retired fire captain and who spent time as a fire academy instructor and holds a university degree in fire science, but who disagrees with several of the things taught by "Mac the Fire Guy." I'd suspect that is true for any field of study as well. Far too often opinions of an instructor are taught to the students as facts. There is nothing at all wrong with an instructor stating opinions, so long as they are differentiated from facts.

 

Everything that we do has some degree of risk. The wise person understands the risks involved and then makes their choices based upon their degree of risk tolerance.

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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You are partially right. Purging is the action required to remove all moisture-laden air from an LP tank. I know you've read about someones LP regulator freezing up in cold weather and they have no gas flow. That is a sure sign their tank should be purged (pull a vacuum in the tank) to remove the moisture inside.

Liquid LP does not vaporize immediately. I have poured liquid LP into a paper cup(demonstration) at seminars on Propane, it simply boils away until the cup is empty, it is not immediate total vaporization-vaporization only occurs on the surface, it takes perhaps 3 minutes for that paper cup to become empty. Barb is correct.

All this has little to do with the thread topic anyway.

 

Can you U tube this for me, I got to see this. Liquid propane poured from a 200 psi cylinder into a cup and watch it vaporize?? I did find a U tube that showed propane being poured into a container where the outside temp was -43 and even then it started to boil violently. I don't believe propane can be poured at room temp. I used to crack the delivery truck hose at dogs acting aggressive in a customers yard that I was trying to fill a tank at. All that came out of the hose was high pressure vapor, no liquid. Never had to do that twice on the same dog. :)

 

Barb, I have credentials also but that point is useless. As a Mech Eng. myself I tried to stay away from people that dealt with drugs. (sorry I couldn't resist Barb, :). A propane tank is never suppose to be filled above 80% so therefor it always has a vapor pocket it the tank. Yes, if the temp gets low enough the regulator may freeze up from frost and also the gas getting too close to the non boiling point of -43 F. It would be useless to purge a tank just because the regulator froze up in cold weather. In my short career in the family propane business, I have never ran into purging a LP tank. You don't purge a gasoline tank just because it gets air in it? Propane is just another gas, only under pressure to keep it liquid.

 

Like Kirk said, there is a lot of confusion and opinions on LP gas. We are not born with this info, it is learned.

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I heard just the opposite. Once in a while let the tank go almost dry to remove the oderant and any of the high boil parts of the LPG. left alone the oderant gets weak and the high boilers build up and prevent the build up of pressure in cold weather.

 

On the other hand oils can build up on the bottom of the tank but in a class A there is no easy way to remove it. A downward deadend stub (sometimes called a drip leg) right after the regulator MAY catch most of that and it can be purged by opening a petcock on the bottom of the stub. This is a problem with cheaper grades of propane (read Mexican). I understand that there are also filters that can be used to remove the oil.

 

Have fun.

 

further reesearch: http://www.bing.com/images/search?q=Gas+Sediment+Trap+Diagrams&FORM=RRIMGI shows these in use in residential systems and mandatory in some. Apparently NOT in RVs <_<

Happy Trails,

 

Florida Mike

EXPERTS AREN'T!! :D

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I got curious and researched that the oderant, Ethyl Mercaptan is a clear flammable liquid and is added to LP at a rate of 1.5 lbs per 10,000 gallons of LP gas. In the real world it is not a issue since most LP tanks might have been exposed to a teaspoon of oderant in there lifetime and most of that would have been passed through and burned with the LP gas. Also a gas trap is good with a Natural Gas system that transports gas through miles of underground piping. The LP trap is overkill on propane systems and even then some appliances do have screens as a filter.

Greg

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I got curious and researched that the oderant, Ethyl Mercaptan is a clear flammable liquid and is added to LP at a rate of 1.5 lbs per 10,000 gallons of LP gas.

Any idea if that has always been the thing added to cause the smell? Back in the late 50's I know that they did invert the 100# bottles occasionally to drain out what they said was a mix of oil residue and odorant. Of course, it could also have been a myth even then.....

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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I know in the 50's Butane C4H10 was a common gas used before the days of propane C3H8 (I stand corrected). I have opened old butane tanks and found them to be quite dirty inside which I thought was age related but could be due to the refinement of the gas. I do remember some discussion at the shop from some older old timers about Butane being a dirty gas.

Thanks Kirk for clearing this up, now I understand all this purge confusion.

Greg

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DIVE TANKS.... yes, BREATHING AIR..... don't run 'em dry 'caus they have to be purged.

 

Propane tanks? Who started this thread about nothing???????

 

Run 'em dry. Bring 'em in. As long as the manufacturing date is within the last 12 years..... good to go.

 

Anyone else is FOS.

Previously a 2017 Forest River, Berkshire 38A, "The Dragonship". https://dragonship.blog/

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Propane is C3H8

Butane is C4H10

 

I think a lot of what is taught at the fire safety seminars for RV is driven by input from the insurance industry. They are going to find someway to push what is in their best interest, whether it is a viable answer or not.

 

In the industrial refrigeration are, I dealt with several flammable and lethal refrigerants in large quantities. We had to deal with propane, polypropylene, butane and ammonia. In dealing with these systems with some 20,000# of refrigerant, we did have to deal with local firefighting authorities. Around the Houston area, the plants often had their own fire fighting people that interfaced with the local government fire departments. With the varied and large quantities of chemicals, the plant fire fighters had to provide training to the local fire fighters as they were not trained on proper fire control.

 

So I think, the RV seminars are influenced by insurance desires.

 

Ken.

Amateur radio operator, 2023 Cougar 22MLS, 2022 F150 Lariat 4x4 Off Road, Sport trim <br />Travel with 1 miniature schnauzer, 1 standard schnauzer and one African Gray parrot

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All of the Buddy Heaters (all of which are propane operated) have built in or external filters. The Catalytic heater company (Olympian Wave ) recommends a filter and also cautions against using propane from mexico because of the oil etc. in the propane. Rember that the gas is pumped and if the quality of the pump(s) is poor it can leak oil into the propane. That can build up and if not removed can easily plug an oven, refrigerator etc. orifice. Remember that the operating pressure for the low pressure equipment is 11 in. Hg or less than 1/2 PSI. , not high enough to blow the debris out of the way.

 

Filter or drip leg is not difficult or expensive, your choice.

 

Have fun!

 

TXiceman, I agree regarding the insurance and legal mumbo jumbo. Have you looked at the list of side effects listed for drugs these days. By listing every possible side effect, including death, the drug companies excuse themselves from any harm as you were "warned". Makes the side effect list pretty useless!!! :angry:

 

Getting off the soap box now :rolleyes:

Happy Trails,

 

Florida Mike

EXPERTS AREN'T!! :D

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