Overhang/Shading question

[uncle bob]

Hi guys

Been to see a large flat glass job at a supermarket, glare is the main issue, large windows 4ft x 10 ft 27 of them 3 high.

There is an overhang that will cause some shading. The glass is double glazed, laminated exterior pane, toughened tempered interior.

Looking at Optitune 15 or ST SYDS equivelent.

Would the shading be an issue?

Thanks

Bob

[TomTint]

I don't think I would be to concerned with filming the tempered side.

[uncle bob]

I,ve spoken to a few film reps/companies and 3 out of 4 say it should be fine as the tempered glass will absorb any heat/energy and its only the light that is reflected out onto the laminated pane.

They all suggested the same type film as I had, either silver 20 or a dual reflective.

The other rep, who I have to say is very knowledgable regarding flat glass applications expressed some concern but only regarding the condition of the laminated pane saying the usuall, that if there was any guarantee that the laminated pane was perfect it would be safe.

Bob

[Jayz81]

Should be fine as long as you are up front and honest about glass breakage/seal failure warranty. Have you considered exterior film ? Might be a good idea if you feel uncomfortable about the situation, or the property manager does. Good luck !!!

[EWF]

There is an overhang that will cause some shading.

Would the shading be an issue?

Bob

Yes. Partial shading will induce an uneven thermal load and that condition is associated with a higher risk.

Although not the only factor by any means, it is part of the larger equation you must take into consideration when evaluating the risks of any particular application. Other factors include (but are not limited to):

Exposure (N,S,E,W)

Glass Size

Glazing Type

Film Selection (particularly TSEa)

A prior history of failure

AIMCAL authored a superb booklet on this topic. Anyone who needs a copy can email me a request at howard@buytint.com.

Most importantly:

Check with your film supplier before you proceed. Better to learn in advance whether or not the application would qualify for inclusion in their glass failure program. Hopefully it is. If not, you need to discuss the risk with the customer in advance and come to a collective decision on how to proceed and who will be responsible in the unhappy event of a failure.

Those units sound expensive. Proceed with caution.

-Howard

Edit-Grammar

[EWF]

guarantee that the laminated pane was perfect

Bob

Confirming this would require dis-assembly of the unit, which is impractical.

-Howard

[suntint]

Agree this best course is to be upfront about the potential for breakage.

When I've seen insulated units break it has almost always been the interior lite - but these units are unusual since the outboard lite is lami, and the interior lite is tempered - which tilts the odds of breakage more towards the outboard lite.

Ordinarily I think silver is the safest since it reflects much of the heat away, but in this case maybe it is better to absorb more heat into the tempered inboard lites, instead of reflecting it back towards the more risky lami exterior lites?

Exterior is safer, but don't know about longevity in usually damp Glasgow.

If your film supplier will warranty for thermal breakage I'd say your probably good, just advise the customer of the risks and limits of the warranty.

[uncle bob]

Thanks for the replies guys.

3 film reps have advised no advers risk due to internal pane being toughened / tempered glass and very little solar energy will be absorbed by the outer laminated layer as mostly its light thats reflected.

They all suggested silver 20 or dual reflective, optitune 15 or 22 or syds15 or 20 and the global equivalent

Bob

[Filmhandler]

We did a similar install this summer. No issues, interior temp glass will be safe. Exterior lami will get continuously cool by outside air.