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Glass breakage due to heat absorption??

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I was talking with a co-worker of mine today about how if you use the wrong film on a window, it could cause the glass to break. (Too much heat held in the glass)

So we got to thinking about what the actual cause would be. For example, on skylites, we've installed Llumar R20... which holds in a lot of heat, and the sun just bakes the glass all day long. But generally we don't have any problems.

Then we may put on something like R15 on windows that are totally south-side, and again, no problems.

The next day install something like V58 and bam.. the glass breaks a week later. (Well, not really, but still. :rollin )

What actually causes the glass to fail?? One thing we came up with is if say a window is partially blocked by a tree... so part of the glass is shaded, the other part isn't. The glass would be unevenly heated, which could lead to the failure.

Any thoughts??

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One thing we came up with is if say a window is partially blocked by a tree... so part of the glass is shaded, the other part isn't. The glass would be unevenly heated, which could lead to the failure.

that is one thing for sure, SHADING is a factor, another is if the glass is tempered or annealed glass, tempered can handle heat to over 200 degrees, so in theory it should not break EVER. we have had tempered glass break before though, one job we stood and watched as the glass compeny took the frame work off around the glass to replace it, the glass installers ahd put a screw into the side of the glass :rollin but they wanted to blame us for it, eventhough it was a glass install problem, they did pay for the glass in the end. things like, how the glass is set matter also, obviously a newer style glass has the rubber gaskets around the window and those allow for the glass to expand and contract, the old fashioned kind that are metal frames and the like are what scare me, if the window can t expand and contract it can break, also I dont know how many times I have had a glass company bring a glass by the shop for me to tint first, then they install it, I noticed thinks like chips in the edges of the glass, unseen things like this causr breakage aslo, stuff you just can not see.

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we did a job last march on a old building that was being renovated, all the glass was regular annealed glass, large pieces like 70 x 80 inches. my boss usually bids the flatglass, he messes up alot :thumb.

first thing I notice is bushes about a foot up from the bottom, the glass is set in the old metal frame work, it also has a partial overhang. this job is like EVERYTHING you dont want rolled into one. as we were driving off I told my boss I thought we should pass on the job, as usual he wouldnt listen to me....he priced the job to like 4000 bucks, there were 22 windows this size, me and my helper got them done in about 6 hours, the NEXT day they called and one had broken out already :tw

I was like I TOLD YA :lol my boss was llike I took out glass insurance blah blah blah, well long story short I have been back 4 times to tint glasses the broke out.....they called last week ANOTHER one broke out, thats 5, my friend told me my boss said "mabey we shouldnt have tinted that place" :tw we put llumar n1020 bronze on it, when I looked it up on the chart we have it registered HIGH on the risk scale for breakage.

flatglass, you can make a ton of money or LOSE your ass trying :rollin

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Everything MDOG said above is true... :thumb

Sounds like his boss is a bit dim which is surprising since he has a personal stake in the matter.

MDOG saw the danger before they did the job and in situations like that the best thing to do is not do the risky film.

If you follow the guidelines from the manufacturer, there should be few problems.

My first flat glass job I ever did was like the one MDOG described, and I had a window break DURING the installation. I learned how to deal with just about every possible difficulty imaginable on that job and even though it sucked at the time I'm glad I had that so early on. :lol

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What we see here is the more reflective the film the less likely it is too break the window. The window will break alot quicker if it's a 35% or lighter. The 20% films don't seem to be a problem as long as they are reflective enough. The only film darker than a 20 that I'll install on a thermalpane is the Slate 10 Panarama. Like the skylight you referred to Roach. Silver 20 is fine. It's more likely to break if you were to put a Stainless Steel 35 on it.

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Out of the last 20 windows we replaced the past six years, I have been there to watch the glazer replace the window. On every occasion I have found damage to the glass, small cracks along the sides, nails, screws, and even a screwdriver in one.

All we ever do is agrivate an existing condition causing the breakage, unless you do install the wrong film. That is why the V-58 cracked the window.

To date I have never had to replace a tempered window or a commercial grade window. Every time it has been all those cheap lousy windows that are out there.

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No film installed which absorb more than 40% of solar heat

No windows larger than 25 sqft

No shade effect during the day (tree,building or part of the roof)

Even then some windows break ,which also had broken if you did'nt install the film.

It is very hard to understand why outof 178 windows installed with Silver 20

only 1 window breaks???

The glazing companies I work for ,tell me that more thermal breakage

appear on windows without film than with film installed.

Only problem is that glass supplier ,immediately tells the owner that it is

caused by the film + they lose there garantee on the glass.

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