Seal failure on tempered dual pane

[NvrLate]

I need some good ol' experienced replies on this one.

I've used Llumar DR15 (dual reflective) for about 5 years on quite a few residential jobs with no issue of stress fracture or seal failure. The film to glass permits it on most any typical dual pane unless over 50 sq ft or if there is some funky shading on annealed. I've also cheated a couple and gone beyond the FTG recommendations a time or two with no issues.

I recently did a wall with several large windows, all tempered, HP low-e, (which the FTG chart clearly permits, not anywhere near the limits) and 2 of the 30 sq ft windows (5x6') and 1 small circle top (about (30x60") experienced seal failure on the 2nd summer.

I'm wondering if anyone has had any experience with this; it seems like the fact that the FTG allows higher heat films on tempered glass would be because of less likelyhood of stress fracture, but does tempering lessen the likelyhood of seal failure?

Fortunately, Llumar is standing behind the glass warranty but I'm trying to educate myself on why these windows failed, to determine if it was a result of the film, or maybe just a bad run of glass.

To those wanting more info-FTG allows a rating up to 10 on annealed, 18 on tempered. DR15 rates a 9 with no shading, but on HP Low-E tempered it rates a 3, and that's the windows that experienced seal failure. Again, do these ratings only apply to glass breakage or seal failure also?

[Ryker]

Glass tempering would have nothing to do with the likely hood of seal failure.  Tempering would just strengthen the glass.  I guess it could help to keep the glass from having as much thermal expansion and contraction though so that could help with the chance of seal failure too...

 

Someone on here said that it has not be proven that film has been the cause of seal failure.... likely just weak seals on those windows..... just be glad you covered your bases with the factory warranty....would not want to have to replace windows on your dime for sure....

[NvrLate]

By the way-windows have direct sun exposure during the am hours, and the sun crosses over top of the house and by 1 or 2 there is no sun exposure. I can see where there may be a horizontal shading as the sun crosses over. But, I can't see how this would affect seal failure.

[NvrLate]

Thanks Ryk you're right about the warranty-especially not these windows!

[Tintguy1980]

F2G does account for temperature in the gap between panes (there is a limit). Sounds as though these were single seal IG units rather than double seal, or not truly HP lowE, or just plain poorly built IG units.   

 

Whether tempered or annealed they both behave similar when heat builds in the glass; what breaks seals is during glass heating and cooling it's flexing outward () and inward )(, the higher the heat, the more the bow outward as the dead space gap expands in volume) and the more cooler temp exist, the more it bows inward (contracting in volume).

 

This bow (or flex) back and forth by the glass works against (or pulls on) the seal to each glass to spacer surface contact around the perimeter and if it is a single seal, it will pop away from the glass creating a leak. For double sealed units (thought to be widely used today) the first seal holds glass to the spacer and the second seal caps off the edge perimeter of both panels and seals in the first seal against the potential for leaks.

[mikebrook_07]

F2G does account for temperature in the gap between panes (there is a limit). Sounds as though these were single seal IG units rather than double seal, or not truly HP lowE, or just plain poorly built IG units.

Whether tempered or annealed they both behave similar when heat builds in the glass; what breaks seals is during glass heating and cooling it's flexing outward () and inward )(, the higher the heat, the more the bow outward as the dead space gap expands in volume) and the more cooler temp exist, the more it bows inward (contracting in volume).

This bow (or flex) back and forth by the glass works against (or pulls on) the seal to each glass to spacer surface contact around the perimeter and if it is a single seal, it will pop away from the glass creating a leak. For double sealed units (thought to be widely used today) the first seal holds glass to the spacer and the second seal caps off the edge perimeter of both panels and seals in the first seal against the potential for leaks.

Learn something new everyday!

[NvrLate]

Thanks guys. Also, I said it failed on the 2nd summer but that's an assumption. This is a vacation home and the owners were in and out throughout the year, the fogging was first noticed during early winter. It has been colder than normal. I assumed it developed during an extreme summer glass temperature situation, but it's possible it may have happened during fall and winter, during the wide temp variations of day to night. It shouldn't have failed though, especially 3 windows. If it had been one, I wouldn't have given it a 2nd thought. Interested in reading as many comments, knowledge and thoughts as y'all want to post. Especially if anyone has had lots of positive or negative success with reflective 15%. (Interestingly, Llumar DR25 actually rates 1 point higher than 15 according to the FTGC, higher heat absorption and less reflection on that one)

[Tinitman]

If it was caused by the film, other panes would have failed.

 

If you ever get a chance to see how windows are made, transported, and installed, you would wonder why all the glass doesn't fail from the abuse.

 

Most likely in your situation, the glass was failing prior to you installating the film. No one noticed at installation, it got worse after time and you were called.

[vquestfilms.com]

One thing to always keep in mind too is that most film warranties that cover seal failure only cover windows that have an OEM seal failure warranty in force at the time of window film installation. A lot of dealers make the mistake of implying that a customer is covered for seal failure when in actuality, they are not. Make sure you do your due diligence on the warranty side of things and inform your customer so that you do not get caught in a bad situation.

 

 

F2G does account for temperature in the gap between panes (there is a limit). Sounds as though these were single seal IG units rather than double seal, or not truly HP lowE, or just plain poorly built IG units.   

 

Whether tempered or annealed they both behave similar when heat builds in the glass; what breaks seals is during glass heating and cooling it's flexing outward () and inward )(, the higher the heat, the more the bow outward as the dead space gap expands in volume) and the more cooler temp exist, the more it bows inward (contracting in volume).

 

This bow (or flex) back and forth by the glass works against (or pulls on) the seal to each glass to spacer surface contact around the perimeter and if it is a single seal, it will pop away from the glass creating a leak. For double sealed units (thought to be widely used today) the first seal holds glass to the spacer and the second seal caps off the edge perimeter of both panels and seals in the first seal against the potential for leaks.

 

There is a whole economy that is generated by expansion and contraction. 

 

Did you ever see the software that was created about 7yrs ago to simulate expansion and contraction? It seemed like such a useful tool but it seemed to just disappear off the map, I never see it anywhere. Crazy how stuff just disappears like that.

 

Here is a fun little research project if anyone wants to take a stab at it. Try and dig up statistical IGU seal failure data ratios from the glass industry. And if you manage to find something current, then try and find IGU seal failure warranty replacement data from the glass industry. There is old data for window film but try and find data for plain old OEM glass... let me know if you find something current.

 

If it was caused by the film, other panes would have failed.

 

If you ever get a chance to see how windows are made, transported, and installed, you would wonder why all the glass doesn't fail from the abuse.

 

Most likely in your situation, the glass was failing prior to you installating the film. No one noticed at installation, it got worse after time and you were called.

 

Valid point. What happens if you never tint the window? If film is the sole culprit then logic would say that seals should never fail on a clear IGU, right?

 

A lot of IGU's get shipped from fabrication facilities at sea level over mountain passes. The vents on these units sometimes fail so they come DOA. The problem as you said is that the seal failure is not visible until the absorbing material (BTW... why do they have to put that stuff in the spacers if the IGU's are so solid to begin with? ) in the spacers fully saturates. In some of the less humid regions it can take a few years until you see moisture. So along comes the window film guy who installs on a nice looking clear IGU and them bam!... seal failure.

 

 

[Tintguy1980]

IWFA has a document copyright 1998 "The Use of Window Films on Insulating Glass Windows" that speaks to percentages with and without film applied. Says most window makers at the time were not members of an association known as Sigma who set high performance standards for IG unit construction. The study funded by the IWFA (Edit: AIMCAL) for the document determined that IG units are no more prone to have seal failure with or without film installed. I would provide a copy but do not wish to do so without AIMCAL's permission, hence violate their copyright. If anyone wants to lay eyes on this report they may simply contact the IWFA directly.

 

As to software, I have not seen or heard of it but I do know of a means to determine temperature of the air or gas space; haven't seen or used any such software and would probably find myself intimidated by its complexity.