Argon pressure chamber filled to match destination altitude?

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When asked about Argon leakage did your rep convince you that he understood the issue thoroughly?

Was convincing and explained it to me
No votes
Regurgitated sales training talking points without deeper understanding
Evaded the question or made stuff up
Total votes: 3

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Argon pressure chamber filled to match destination altitude?

#1 Post by 90min_to_Vail » Thu Feb 10, 2005 12:12 pm

I need to establish whether the following is true: Are Marvin (or any other) insulated window units Argon filled in a pressure chamber that matches the atmospheric pressure of the destination (eg. >5000ft, Denver)?
If yes, are there no ill effects for shipping the product to Denver?
Reason I'm asking is that I've heard contradicory claims by different professionals, and did not find answers on Marvin's website. The whole Argon story is murky and after talking to 10 window reps (home show, on visits) none seemed to really understand the science or was able to relate it.
I'm waiting to hear a response from Marvin directly which I'll share when it comes in.
I did read in a Marvin pdf that they recommend capillary tubes for altitudes over 3000ft but do not install them into insulated units just for transit through higher elevations, so that may indicate the windows/seals can deal with relatively short term pressure differences. Still, won't the capillary tubes let much of the gas escape during shipping?
A longtime Marvin installer yesterday told me any Argon would be gone within 7 years anyway - but others claim a 1% leakage per year. What gives?
If this becomes a lengthy thread we'll call it "Jason and the Argon-Outs."

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#2 Post by RC » Thu Feb 10, 2005 1:41 pm

I think window companies are worried that hand-held non-destructive argon measuring devices will get in the hands of people to test installed windows. Can you imagine the liability?

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Marvin answers: if >5000ft=breather tubes=no argon!

#3 Post by 90min_to_Vail » Thu Feb 10, 2005 7:25 pm

I received this fast and enlightening reply from Marvin, below:
"Your question about argon filled units is going to be affected by the elevation of the location where it is going. As a general rule, capillary tubes, also known as breather tubes, are recommended in one lite insulated units installed in elevations of 5,000 feet or more above sea level. Capillary tubes are recommended to be installed into smaller or divided lite units with one side of glass less than 12" in length if installed in elevations of 3,000 feet or more.

Marvin does not install capillary tubes into insulated units for transit through high elevations, such as insulated units shipping to the west coast through the Rocky Mountains. Final installation of the insulated glass unit determines whether or not a capillary tube is necessary. Units with capillary tubes cannot have agron gas in them."

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#4 Post by earwax » Thu Feb 10, 2005 9:23 pm


You are right about the litigation. I have played with one in a manufacturing faclity. They are really neat and work well. They are in the process of getting a standardized test that will be an industry standard for them right now, last I heard. I now that manufacturers are throwing up road blocks and screaming murder about them.

About the Argon fill. Cap tubes should be on the top of the windows pointed downward. Argon gas is heavier than air. The belief is that the windows will concave on itself is you do not have a tube. By puttin one in the air presure equalizes and teh argon does not get out . It is like taking a cup of water into a filled sink and putting it into sink. Once it reaches the top, water fills it in. if you take it out the water stays in. If you squeeze the cup, water spills out. Cap tubes stop the squeeze and thus the release of argon.

This is a crude explanation, but hope it helps.

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#5 Post by Oberon » Thu Feb 10, 2005 9:45 pm

No major company that I am aware of fills their IGU's with argon to a pressure greater or less than the pressure at the location where the IGU's are filled.

Marvin IGU's are manufactured by Cardinal and they are filled and sealed in a vacuum chamber.

Cardinal (per their website and literature) has tested their argon filled IGU construction in units that pass over the mountains and they warrant those units against any sort of damage caused by the change in atmospheric pressure during the trip.
But, at the same time, they do not recommend that these units remain at altitudes 5000' above the altitude where the IGU's were manufactured.
The pressure in the IGU that much above the manufacturing altitude will cause the windows to bow out significantly and will cause a very noticeable visual distortion.

Breather tubes and capillary tubes are not exactly the same thing.
A breather tube is short, has a relatively large opening, and is aluminum.
A capillary tube is long, has a very narrow opening, and stainless steel.
Both devices are designed to equalize pressure within an IGU at high altitudes, but there are a few differences.

Breather tubes are desgined to be crimped closed when the window is installed.
Capillary tubes remain open to allow for barometric pressure changes. Because of the nature of the capillary tube and because the air at higher altitudes tends to be very dry, moisture isues within the IGU is not considered to be an issue, despite the open tube.
Breather tubes tend to allow significantly more moisture into the IGU en route to the eventual installation site than do capillary tubes due to the basic design of each device.

There is a very common notion that argon gas disipates out of an IGU in 5 to 7 years. This was common at one time. It is no longer true of the top manufacturers using the newer spacer systems, but many salesfolks, and some knowledgeable folks will still tell prospective buyers that it is true.
Long term weathering and accelerated laboratory testing of several of the newer spacer / IGU systems is pretty conclusive that the better products will hold argon for the life of the window unit - 50 years or more.

Actually, several IGU / spacer manufacturers (particularly EdgeTech and Cardinal) are pushing for the hand-held testers to have much more common usage in the marketplace in order to prove that their products do actually perform as advertised.

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Argon at altitude

#6 Post by MikeM » Mon May 23, 2005 11:41 am

So is it fair to say that an argon-filled window, installed at 6000', will have an effective NFRC rating somewhere between the argon-rated number and the air-rated number?

Is it a bad idea to have argon at altitude? Seems to me whether it's argon or air, the cap tube will allow some of the gas out, and the insulation is weaker than if you were at sea-level. Wouldn't you still have better insulation with less argon vs. less air?


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