Skyscraper Windows - Research Project

[New User]

Hey everyone, I hope this is alright of me to ask, here...

First off, I don't really have anything to do with Skyscrapers... I'm a writer doing research for a project I'm working on. Most the info I found online has been a little fuzzy and I figured this would be a good place to get a variety of experts' opinions

So: My question is about Skyscraper windows and the type of glass used. Basically, I wanted to know if it was tempered or otherwise strengthened glass - what it would take for an average person to break (with one's body, moving quickly into it) from the exterior and interior - and anything related.

I know glass and windows in skyscrapers are designed to stand up against strong winds and weather, but are they as strong or more fragile than most people think?

Thanks a ton for your help!

[Tony]

http://en.wikipedia.org/wiki/Garry_Hoy

[New User]

Hahaha yeah, I remember hearing about that. Interesting that the glass didn't actually break.

[JohnMarko]

None of the glass is "plain" glass. ALL of the glass on glass curtain walls is a structural laminated and tempered glass, able to withstand a certain amount of horizontal force (puncture), such as leaning against the glass.

The design above what is required for wind and earthquake resistance is only somewhat more than required for wind and earthquake alone.

We had a highrise where someone had placed a "chain" of paintings against the glass - not the frame - of the exterior curtain wall - and there was no problem.

The only cracks were for construction/installation related issues - such as someone accidentally hitting a pane.

It is a building code thing - at least in most of the developed world where codes are in place.

[dchan]

Thank you, John, for your responses to these engineering threads. Much appreciated to have some expertise from a professional. What's your background?

[JohnMarko]

Originally Posted by dchan

Thank you, John, for your responses to these engineering threads. Much appreciated to have some expertise from a professional. What's your background?

I'm an Architect - been one professionally for over 30 years now...

[mthd]

as a further clarification - the typical assembly for a skyscraper in most jurisdictions with reasonable climates is two 1/4" thick pieces of glass held apart 1/2" by an insulated spacer. typically the first 'inside' face (the #2 surface) is coated with a low-energy spectrally selective coating.

depending on the size of the panes within the curtain wall, one or both of the pieces of glass will likely be tempered or heat-strengthened. laminated glass is not often used in these assemblies except when required for acoustical or aesthetic purposes. the pvb plastic used to laminate the two pieces together can provide good acoustical performance, blocking different sound frequencies than the glass or air space. in these cases the 'window' would actually consist of three sheets of glass. two laminated together and then joined to a third with the 1/2" insulation spacer.