Initial fill of new Propane tank fact or fiction on purge needed

A new tank gets purged - period - at least here in Canada. Purging where I live consists of a brief crack of the fill valve. Then disconnect and open the tank to vent to ambiant pressure. Done. No charge. All portable tanks (20 to 100 Lbs). are filled on a scale. Every time a tank is filled (here) the attendent checks the date stamp on the tank *and* the physical condition of said tank.. A tank that had been re-painted, is too rusty, dented etc. may be refused. Aluminum paint is automatically rejected! On a lighter note; What is it about propane that triggers this group? I think I will call this phenomenon the 'King of the Hill' syndrome. Regards. Ken.

Hum - now with the new OPD valve - item 3 requires the valve be taken off. It won't drain out upside down. Maybe through the escape valve - maybe.

Martin

No, this is not purging. Even a "full" gasoline tank has some headspace containing a mix of fuel vapor and air. A near-empty automotive fuel tank will contain a large headspace with a potentially explosive fuel-air mix.

I don't know, Some of what's been posted is accurate but lots of this 'information' is inaccurate.

And purging a gasoline tank? What a troll!

I don't miss working with propane. Not because it can be explosive or that it boils 44 degrees below 0, could be an interesting situation where your feet are being frozen solid while the rest of you is betting burnt to a crisp.

After some of the stuff I worked with i the Military and in aviation propane is pretty pussy.

I don't miss working with propane because of the customers and some of the Yahoos I worked with. 99% of the people who have propane either live in trailer parks or live someplace without natural gas service. The reason there isn't NG service is because they live in the middle of nowhere. Enough of the customers kept chickens and cows in the house. Bobtail drivers need to know the area, how better to know an area than to have grown up there. Who were these people ? The ones living in chicken and cow houses.

Ok, so maybe this is an exaggeration. But it sure seemed like it.

Then there were the drive in customers, those bringing small cans (up to

100 lb.) and motor homes.

There's the guy who wants me to put a little extra, AKA do an overfill, in his 20s because he's going hunting and doesn't want to run out. I tell him I can't do that, he says the other guy does it all the time. ?? Reallllly? and whose this other guy? He describes a co-worker. I say I'll have to ask him about that but no, I'm not going to overfill. The guy gets pissed off. I tell him he's lucky I filled the tank he painted black but since it's winter I think it will be Ok. Now that becomes an issue.

Then there are the people who bring cans in that are rolling around the trunk of their car. And they expect to leave that way. When your doing a cylinder exchange ar HD or the local cig and beer stop they don't see how you bring them in or how you leave with them so their asses are covered. Unfortunately our fill stations were *right there*, I could see.

Try telling someone that's 'always done it this way' and the 'other guys' never said anything (see chicken and cow houses) the dangers of unsecured tanks and transporting a tank with the relief valve in liquid, and how your (I'm) not going to be responsible for the law suit. Not to mention how your not to transport cylinders in an enclosed area or passenger compartment.

There was the young punk who pulls up to the dock (where motor fuel tanks are filled) in his bosses dump truck and literally throws the tanks on the dock. Talk about a sky rocketing stress level! I ask if he's aware of the possibility that throwing cans around could cause a fire and we could get burnt. He says, this is no shit: We all got to die sometime. I failed every can on a visual.

Then there are the roofers. Roofers use high btu torches so in colder times of the year their tanks frost off. As the torch is dyeing they turn the torch on the tank. I've seen paint pealed from the heat. I had one roofer tall me how sometimes they get the can so hot the relief valve blows off, and boy that's neat if a little too exciting. Amazing none of them got killed. How do roofers get the empties (sometimes there still half full because of frost off) off the roof? They drop them. Lots of foot and head ring damage, lots of dents and gouges. Failed damned every tank they brought me once. So they bought some new ones which I purged and filled and failed the next time I saw them because of the char marks and dents. This story has a bright spot as the roofers bought their own dispensing station so they wouldn't have to put up with me. Cool, we can't be responsible for tanks they fill.

Then theirs the motor fuel/ motor home people. They pull in and first question from me is anyone in the motor home. For the most part their unprepared for this. They answer yes next words from me are everyone has to be out of the motor home before I can fill it. For the most part that's news to them. Noone in (pick a state) makes us do this. Yeah, I know, but not only is it the law but it's also a good idea. Some people want to argue. Sometimes they say no ones in the camper/ motor home and while I was filling the tank I feel the home start rocking. Their whole families inside, they didn't want to be inconvenienced. I've even had people get offended when I say removal of their pets are optional, seems they want me to think their pets are as valuable as humans.

Then there's the placard issue. Read one way you count only the LPG, read another you count the can and LPG. The first way 3 33's can be carried, read another only 1 33 can be carried. I doubt the people who wrote the law understand it.

Working with LP wasn't bad, working with the people who use it was unacceptable.

Actually #3 would require the removal of any valve. OPD or otherwise.

Wrong. Very wrong.

That was an improper purge, and if liquid was coming from the bleeder valve it was already near or at capacity.

Nope.

The tank had either dry air or N2 in it to prevent air and moisture from entering the tank which would cause rust and odorant fade. You really did yourself no favor by bleeding it off.

Read my previous post on odorant fade, open the link and read the article if my words not good enough.

I hope they also opened the bleed valve.

Whether it's a portable, motor fuel or stationary tank the bleed valve must be opened.

The bleed valve is attached to a dip tube. The dip tube extends into the tank like a stand pipe in reverse. The bleeder valve spits when a tank is filled to it's designed capacity.

If you need to know the designed dip tube length look at the collar on the tank. There will be a stamping: D.T. XXX where the XXX is the length of the needed tube.

As I said the bleeder is to be opened every time the tank is filled. Period. Scales are known to be inaccurate, OPDs are not to be trusted. The dip tube is always right, assuming it's in place and the proper length (I have a story about my former boss and dip tubes which I will spare you, take my word that sometimes the wrong ones are installed).

A missing dip tube is somewhat rare.

Listen while your tanks being filled. If a tank fills to 100% it makes a very distinctive blooeeep sound.

If you pick up your tank and shake it and you can't feel the fluid sloshing it's been overfilled (or it's empty).

huh?

I have never seen a dip tube on an LP tank.

I've only seen them filled with the tank on a scale.

Dave

"Mark" wrote

Mark, very good post, thanks. You reminded me of a motor home fire I happened upon. It was at a busy shopping district just outside of Portland Oregon. The firemen had about a

1/4 mile radius marked off. The motor home was sitting along side a propane filling station behind a gas station. The firemen were hosing the motor home and the huge propane tank just along side of it. I managed to find a parking spot with a good sight line to watch. The motor home was a total loss, totally engulfed. Then all of the sudden kaboom! I thought that maybe the big propane tank went, but no it was still there. I figure the smaller tank in the motor home went. Wasn't much left of the motor home after that. I never heard if anyone got hurt. Very scary scene.

Lane

yes, they used the bleed valve, too. the only time i see that left closed is on a large (80-100gal motor fuel) that is nearly empty. they open it past 1/2 way thru the fill, others open it before filling.

years and years ago, some operators did not open the bleed until nearly full, no matter what type of tank. guess they didn't like to breath it. that was before all of the new laws. ymmv, --Loren

Hey, I'm not sure what gas was in there, I just assumed it was air. Tanks are cheap, you think some manufacturer is going to go out of his way to put CO2, nitrogen or argon in there just to check for leaks? They can't be easily shipped with any flammable gas in there, either, lots of DOT regs on that. No matter, if it doesn't dissolve in propane liquid, you're still going to get excessive pressure build-up. Think what would happen if you took a closed tank full of pressurized air and started pumping in water. It's going to raise the pressure even more, right? Air will dissolve in water a little and I don't know the solubility of gaseous air in liquid propane(and have no real willingness to find out), so the cases may be a little different. You'd still end up getting more pressure in the tank than just what would be generated from vaporizing liquid propane at ambient temperature in the tank. Purging the tank the first time its filled is a pretty easy thing to do to avoid any possible problems.

Stan

hmmm, i thought we decided they wouldn't blow up in a fire? maybe it got hot enough? maybe it was the hw heater, somehow? --Loren

...>

the only situation that i asked for and received a "packed" fill was out on a freeway access road w/out of state plates on my propane powered 4x4. the guy asked how far it was going that day and would accomodate me, sometimes to 96%, depending on ambient temp.

i did it because of price, usually cheaper out in farmlands, never would fill in the cities. it helps if your rig is newer, clean and towing.

--Loren

Please excuse my ignorance on this...

I pulled the valves out of two 100lb LP tanks, and they looked like ordinary tank valves. No dip tube or anything.

Does this have something to do with the new valve style?

Dave

I don't know much about propane, but everything I have read says nothing about explosion hazard, maybe because air in the tank isn't one. If you have ever had a tank that has air in it, you can figure out that the main problem is that a bubble of air goes through and the burner quits. That means keeping an appliance going is a problem. That's bad enough, but some appliance (like outdoor barbecues, and many RV stoves, have no safety features, so after the bubble of air, propane follows and spills out, causing an explosion hazard.

The "i think" answer was wrong, the question was wrong (or just sarcastic). Explain the explosion potential of air in a propane tank? And, there is no explosion potential in a gasoline tank, the air/fuel ration over the liquid gasoline is too rich to burn. Right at the filler opening is a different question.

I suggest you research that.

others here will have better knowledge, but no, nothing to do with the OPD. my experience is with motor fuel and bbq grills, over the past 30yrs, always, iirc, an 80% indicator/screw or valve. if part of the main fill/supply valve, there s/b a tube protruding down, maybe broken off? otherwise, on a 100gal motor fuel tank, the overflow is a smaller, dedicated valve with a tube attached. --Loren