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

Just what is involved with filling a new propane tank. I just bought a brand new 100# tank. Took it to a gas supplier to get filled, and they
want a $25.00 initial fee supposedly to purge it..........what gives. If its empty its empty. Its got the standard type of valve (OPD not required on a 100# cylinder) so it can be opened and any air inside can be vented to the atmosphere. Am I missing something here? Called two others and they also said the tank needs to be purged since its new.........I have bought new 20# and never had to have them purged . I smell a rip off for some reason.
Maybe I just need to transfer some gas to give it a used smell into this new cylinder and then act like its been filled before. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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Have you considered the explosive potential of mixing propane with the air (oxygen) contained within the tank? Once the tank has been purged, it should be free of oxygen, which is the chief reason for purging them originally. You dodged a bullet if you didn't have other tanks purged.
Harold
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Tis SOP! Will prevent problems down the road. You have to get all the air/oxygen & moisture out, you just want propane vapor/gas. But sounds like $25 is a bit much! How much ya paying per gallon for the propane? The last time I did this, it was like $5 more for the purge.
Lane
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Roy wrote:

So, what is considered a "safe and acceptable" standard purging routine for propane containers?
Does it involve evacuating the cylinder to some negative pressure (without imploding it of course) and then backfilling it with propane?
Or is it some number of cycles of squirting in some amount of propane and letting the air/propane mixture vent out of the container?
Jeff
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Jeff Wisnia (W1BSV + Brass Rat '57 EE)

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Jeff Wisnia wrote:

Assuming the tank is built to take significantly more than 2 atm of positive pressure, could you possibly implode it even if it had a perfect vacuum inside?
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PhysicsGenius wrote:

I dunno for sure, but probably not.
Though if you think about it, a fire hose can hold a lot of positive pressure but will easily collapse under vacuum. It's probably a matter of the physical properties of the tank material, and it's shape, isn't it?
I only mentioned it to show I'd thought of the possibility, so some smart ass who knew for sure thst it would collapse didn't seize the opportunity to jump all over me about it. (G)
Jeff
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Jeff Wisnia (W1BSV + Brass Rat '57 EE)

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there was a thread in rcm a couple of years back about rail and truck gas transport tanks collapsing, after being serviced or repaired. the tanks were at closed up at 1 atm, (IIRC). --Loren
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Jeff Wisnia wrote:

<snipped>
Googled this up at several locations...:
********************************************************************************************
Have your LP-gas container purged. It only takes a few minutes and your LP-gas dealer is equipped to perform this service (see NPGA bulletin 133-a).
To purge a container, the following steps should be taken:
1. Purging of containers should be performed in an approved area (see NFPA #58)
2. Determine if the container pressure is zero. Should the container contain only air pressure, the air may be vented directly to the atmosphere through the service valve.
3. If free water is present in the container, it should be drained.
4. Pressurize the container to approximately 15 PSIG with LP-gas vapor. Never purge with liquid LP-gas; to do so will cause the moisture vapor to chill and remain in the container.
5. Fully open the container service valve and vent safely to the atmosphere.
6. Repeat the fourth and fifth steps for a total of five purgings.
***********************************************************************************************
Jeff
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On Wed, 17 Dec 2003 20:56:48 -0500, Jeff Wisnia

And exactly how is doing this making the tank safer than if it were filled without purging?
As soon as the tank goes from zero pressure to 15psi the first time, the contents are no longer an explosion hazard. So why pressurize and vent?
Is it simply to remove air because the air may contain moisture?
Dave
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"David A. Webb" wrote:

Of course, the possibility of ending up with an air/propane mixture in the explosive range is infinitesimally small if you do put above some minimum amount of propane in. But it can't be guaranteed to be so for every idiotic thing some moron might decide to try, so the reg writers play it safe with that CYA procedure.
I refuse to get sucked into this one again dammit!

Couldn't hurt. IIRC water can diminish or remove the odorant which is added to propane so people can smell leaking gas.
Happy Holidays,
Jeff
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Jeff Wisnia (W1BSV + Brass Rat '57 EE)

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Jeff Wisnia wrote:

TOO LATE! (You just were sucked into it ;-) )
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I had this done (for free) with two new tanks (20lb) that I purchased. The guy doing stated that if the moisture is not purged from the tank, then the valve may freeze up when in use. This would kill any output from the tank.
I filled mine at a Flying J gas plaza. I have also had good luck using smaller mom/pop places like the local feed mill and a small one man used trailer business. I realize that the 100lb probably needs to be filled by a truck coming to you, but what the hey ...
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"David A. Webb" wrote:

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.
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On Wed, 17 Dec 2003 20:56:48 -0500, Jeff Wisnia

Well I can buy the reasoning behind it, but at 25 a whack is out of line. I'll carry it to the dealer that I usually use to get my fills. These others were on my way home and I stopped by to see about getting it filled. The others I called on the phone, as my regular dealer is closed today after 12 noon. He has been in business for 49 years now, so he should know what the story is and how to handle it.
I pay $7.35 for a 20# refill from this fellow. But if there is propane in the tank he will weigh it and only charge you for what he puts in it, unlike the others that you pay a flat fee regardless of how much may be left in it. Thats one reason I was going to get it filled at the other places as my dealer is further away and these were on my way and the tank was empty anyhow. I sure don;t know how folks pay those high prices at places like Lowes and wally world for 20# refills.
Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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Weight it? Flat fee? I've never had either of these done. Every place I've had propane tanks filled had a meter on the filling hose and measured what went in.
Lane
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lane wrote:

And that's the exact reason OPD valves were mandated.
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Mark

N.E. Ohio
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On Wed, 17 Dec 2003 19:40:24 -0800, "lane"

By LAW a tank without an overfill protection device MUST be filled by weight. It may only be filled to 80% of it's capacity. Now the fuel may be metered, and charged by the standard litre - but MOST places filling BarBQ and recreational tanks charge a flat rate for refills - it's up to $11 Canadian most places here now, and a lot charge more than that. Minimum 3 times what you pay for motor fuel propane. Ripoff. And the purge on a new tank is MANDATORY. Not optional.
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Hey Clare,
That reminds me of something happened to me last year. I took a 20# in for a refill, and also one of those ones that is used in a horizontal position as fuel for a lift-truck. They are maybe two or three times the size of the 20 pounder, but are aluminum. The service depot charged me less to fill it than the 20 pounder flat fee of $ 12 Cdn, but I just assumed that maybe it wasn't empty.
Take care.
Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXX .On Thu, 18 Dec 2003 04:39:15 GMT, clare @ snyder.on .ca wrote:

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Well my dealer did not charge for a purge. He stated the main reason they are purged, is, even though the factory makes and pressurizes these tanks before shipping, when they are setting in storage it very common for folks to open valves etc. This allows atmospheric pressure containing moisture to get in the tank. This moisture can freeze and create a stoppage of gas flow during use. Its not to prevent an expolsion etc,. merely to keep the valve and its orifice from freezing up. He stated that other than freeze up potential its relativerly harmless, and its not going to cause any dodgeing of bullets.
He also stated they use alcohol that they pour into a tank to help remove any accumulated moisture if need be. He did not charge me to purge the tank. Pretty nice old fellow. He must know what he is talking about as he has been doing it 49 years now.
He showed me a tank that had moisture accumulated inside of it, and was allowed to set with the valve open after it was empty, and from what they figure it sat this way in a shed on its side, for many many years. On filling the tank (prior to the OPD valves and enforcement of 12 year certiify check) the tank spit down the side for about 10 inches long, looked just like a sawzall made the cut..... At 100 deg there is approximately 200# psi and at - 44 deg there is 0 pressure.
Anyway now I am topped off on all my tanks and ready to make some serious moten metal starting tomorrow. I got an order for a batch of aluminum and bronze sundials and some other decorative cast items from a concrete garden statue manufacturer, have 3 wheels to cast for my bandsaw, as well as a blade guide bracket, and table pivots. Spent most of the afternoon making a few more flasks and raming up molds for tomorrow.
Thanks for all the input on my initial question on purging.
Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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Hey Lane,
And here, it's done with the tank sitting right on a special weigh scale.
Take care.
Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXXXX On Wed, 17 Dec 2003 19:40:24 -0800, "lane"

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