How safe are glass walls and windows?
December 10, 2010 11:51 AM Subscribe
Will highrise glass break?
Here in Vancouver, a lot of highrise buildings have glass walls and windows. Many of them are low to the floor. How strong are these walls? Are they likely to break? For example, our daycare playground has glass walls all the way around it and so does the preschool. And the trade and convention centre has slanted glass walls that you can lean on. A friend freaked out that her childcare facility has windows that allow children to see two storeys below and she wondered about the safety too.
A glazier who inspected the windows in my highrise building told me that windows are not an inspected trade in Vancouver. So I wondered how safe these are. The glazier told me my lower windows are tempered glass and double thick and would have to be hit with an extremely hard object twice to break right through. But I don't know about all these walls and so on.
Here in Vancouver, a lot of highrise buildings have glass walls and windows. Many of them are low to the floor. How strong are these walls? Are they likely to break? For example, our daycare playground has glass walls all the way around it and so does the preschool. And the trade and convention centre has slanted glass walls that you can lean on. A friend freaked out that her childcare facility has windows that allow children to see two storeys below and she wondered about the safety too.
A glazier who inspected the windows in my highrise building told me that windows are not an inspected trade in Vancouver. So I wondered how safe these are. The glazier told me my lower windows are tempered glass and double thick and would have to be hit with an extremely hard object twice to break right through. But I don't know about all these walls and so on.
Not all glass is similar. Some is stronger than others.
I don't know what you mean by "inspected trade" but I can't imagine that Vancouver doesn't have some sort of minimum strength standard for glass that is used in high rise buildings.
posted by dfriedman at 11:54 AM on December 10, 2010
I don't know what you mean by "inspected trade" but I can't imagine that Vancouver doesn't have some sort of minimum strength standard for glass that is used in high rise buildings.
posted by dfriedman at 11:54 AM on December 10, 2010
When designed poorly, they occasionally fall out.
posted by bondcliff at 12:00 PM on December 10, 2010 [1 favorite]
posted by bondcliff at 12:00 PM on December 10, 2010 [1 favorite]
It is glass, it breaks.
The question is, how much psi (pounds per square inch) is needed to make it break.
The breaking point on glass can vary tremendously.
Any architect or contractor worth their salt would be using something appropriate for the building. That said, if it is not being specifically inspected, then people could cheat. But cheating on something like that is eventually going to come back to you - and for most of the people building these buildings, risking their professional license to save 10grand on glass costs is not worth it.
posted by Flood at 12:06 PM on December 10, 2010 [1 favorite]
The question is, how much psi (pounds per square inch) is needed to make it break.
The breaking point on glass can vary tremendously.
Any architect or contractor worth their salt would be using something appropriate for the building. That said, if it is not being specifically inspected, then people could cheat. But cheating on something like that is eventually going to come back to you - and for most of the people building these buildings, risking their professional license to save 10grand on glass costs is not worth it.
posted by Flood at 12:06 PM on December 10, 2010 [1 favorite]
This would be covered by the BC Building Code. Unfortunately electronic access isn't free. Vancouver Public Library or UBC Library should have copies on hand -- the BCIT Library definitely will.
posted by randomstriker at 12:08 PM on December 10, 2010
posted by randomstriker at 12:08 PM on December 10, 2010
I think if the question is "are they likely to break," the real answer is "no", or it would, you know, happen occasionally. Have you ever heard of this happening in Vancouver? Anywhere? Many, many highrises have floor-to-ceiling glass windows? I'm not going to say it never happens, but a (granted, cursory) google search returned about 2 instances ever, and you'd think if it happened more you would have heard about it.
posted by brainmouse at 12:23 PM on December 10, 2010 [1 favorite]
posted by brainmouse at 12:23 PM on December 10, 2010 [1 favorite]
Any glass like you describe is definitely tempered glass, and can be incredibly strong. I once worked a demo project where we were just chucking the tempered glass panes into a dumpster from about 30 feet up. I would say that less then half broke.
posted by sanka at 12:30 PM on December 10, 2010
posted by sanka at 12:30 PM on December 10, 2010
Anecdotal evidence: Eric Clapton lost his toddler son when he ran suddenly at the window, breaking it out and plunging to his death.
Rare but possible.
posted by IAmBroom at 12:31 PM on December 10, 2010
Rare but possible.
posted by IAmBroom at 12:31 PM on December 10, 2010
I don't have a copy of the '06 code, I'm not currently in the industry, but in my 1998 code,
windows above the 2nd storey are covered in section 9.7.5.4:
So basically if a window is above the 2nd storey, it's treated as a balcony guard in terms of There are also a bunch of different standards that window glass has to conform to.
posted by jjb at 12:44 PM on December 10, 2010 [1 favorite]
windows above the 2nd storey are covered in section 9.7.5.4:
9.7.5.4
1) Windows in public areas that extend to less than 1m from the floor and are located above the second storey in buildings of residential occupancy shall be
a) protected by guards in accordance with Section 9.8., or
b) non-openable and designed to withstand the specified lateral loads for balcony guards as provided in Article 4.1.10.1.So basically if a window is above the 2nd storey, it's treated as a balcony guard in terms of There are also a bunch of different standards that window glass has to conform to.
posted by jjb at 12:44 PM on December 10, 2010 [1 favorite]
The Garry Hoy article says that the glass popped, not that it broke. In high rise glass curtain walls, the windows are sometimes held in place with nothing else than tape.
posted by StickyCarpet at 12:47 PM on December 10, 2010
posted by StickyCarpet at 12:47 PM on December 10, 2010
Any glass like you describe is definitely tempered glass, and can be incredibly strong.
Unless the corner is dinged, or the surface is hit with a hard, pointy object such as an ice ax.
posted by StickyCarpet at 12:49 PM on December 10, 2010
Unless the corner is dinged, or the surface is hit with a hard, pointy object such as an ice ax.
posted by StickyCarpet at 12:49 PM on December 10, 2010
I once had an office on the 13th floor of a 30th floor skyscraper and was there during one particularly bad storm that produced tornados out in the suburbs. The windows flexed in and out with amazing force but none of them broke. Friends on higher floors said that the glass flexed in far enough that the gaskets around the windows were breached which allowed water into the floor. However, none of the windows broke.
During the Kobe earthquake of1995, the windows at the airport survived.
In short, glass can be pretty tough.
posted by mmascolino at 1:06 PM on December 10, 2010
During the Kobe earthquake of1995, the windows at the airport survived.
In short, glass can be pretty tough.
posted by mmascolino at 1:06 PM on December 10, 2010
A lot of that storefront/office space window glass is actually two sheets of tempered glass with a thin, tough layer of plastic sandwiched in between.
That construction make it super tough: you can swing chairs at it without breaking it. You can see it in action when protestors smash the windows in a Starbucks, for example: the glass shatters but doesn't fall apart.
It generally takes something like a desk or a large rock or a big metal newspaper kiosk to bust through that stuff. The daycare kids could throw themselves at it all day long without putting a scratch in it.
posted by Aquaman at 2:01 PM on December 10, 2010
That construction make it super tough: you can swing chairs at it without breaking it. You can see it in action when protestors smash the windows in a Starbucks, for example: the glass shatters but doesn't fall apart.
It generally takes something like a desk or a large rock or a big metal newspaper kiosk to bust through that stuff. The daycare kids could throw themselves at it all day long without putting a scratch in it.
posted by Aquaman at 2:01 PM on December 10, 2010
Any glass like you describe is definitely tempered glass, and can be incredibly strong. I once worked a demo project where we were just chucking the tempered glass panes into a dumpster from about 30 feet up. I would say that less then half broke.
Agreed. I too was on a demo for a business who had their giant logo on the window with a permanent decal. We were hitting it with a hammer and it wouldn't break. (The non-logo windows broke just fine. Can't remember if it was safety glass of regular "giant shards" glass.)
That said, all glass (that I know of) weakens with each stressing. Eventually the above window would have broken. So what you don't know is what the status of that individual glass pane is. Or the sturdiness of its mounting.
But in a building where the windows are that accessible, I would expect that the mountings are pretty sturdy. And that the glass would likely be the safety glass like car windows, so an incidental breakage would not likely let the person fall out.
posted by gjc at 2:35 PM on December 10, 2010
Agreed. I too was on a demo for a business who had their giant logo on the window with a permanent decal. We were hitting it with a hammer and it wouldn't break. (The non-logo windows broke just fine. Can't remember if it was safety glass of regular "giant shards" glass.)
That said, all glass (that I know of) weakens with each stressing. Eventually the above window would have broken. So what you don't know is what the status of that individual glass pane is. Or the sturdiness of its mounting.
But in a building where the windows are that accessible, I would expect that the mountings are pretty sturdy. And that the glass would likely be the safety glass like car windows, so an incidental breakage would not likely let the person fall out.
posted by gjc at 2:35 PM on December 10, 2010
When designed poorly, they occasionally fall out.
They sometimes do this by design. I used to work in this building in downtown San Francisco.* We were told the windows were designed to shear off of the building if there was a major earthquake, which would have been unpleasant for both the people on the street and for us, since our desks were pushed up against the windows so we could enjoy the views. I had visions of suddenly being 15 floors up with my desk like a parachute Wile E. Coyote-style.
* By the way, all of downtown is built on landfill based on sunken ships, rocks, and dirt.
posted by kirkaracha at 2:51 PM on December 10, 2010
A glazier who inspected the windows in my highrise building told me that windows are not an inspected trade in Vancouver.
Well, sort of. In normal construction in BC, the only trades that are inspected on their own are electrical and gas fitting. Everything else is inspected by building inspectors for compliance to building codes (in your case, the Vancouver Building Bylaw). As jjb notes above, there are specific requirements for any glazings near the floor. While it is theoretically possible for a lower-spec glazing to have been substituted for the specified glazing and for the building inspector to have failed to notice, it isn't very likely.
posted by ssg at 3:25 PM on December 10, 2010
Well, sort of. In normal construction in BC, the only trades that are inspected on their own are electrical and gas fitting. Everything else is inspected by building inspectors for compliance to building codes (in your case, the Vancouver Building Bylaw). As jjb notes above, there are specific requirements for any glazings near the floor. While it is theoretically possible for a lower-spec glazing to have been substituted for the specified glazing and for the building inspector to have failed to notice, it isn't very likely.
posted by ssg at 3:25 PM on December 10, 2010
As long as nobody at the daycare tries to throw ceramic fragments from a busted spark plug at the windows, they'll be fine.
posted by Rhomboid at 3:57 PM on December 10, 2010
posted by Rhomboid at 3:57 PM on December 10, 2010
There was the case of the John Hancock Tower in Boston. On windy days, windows would break loose and fall onto the street below. Eventually all of them had to be replaced, at great expense.
The Hancock Tower is a case like the Tacoma Narrows Bridge, in that civil engineers studied it and learned from the mistake. What happened there is unlikely to happen again in any newer building, because they learned what not to do from it..
posted by Chocolate Pickle at 4:16 PM on December 10, 2010 [1 favorite]
The Hancock Tower is a case like the Tacoma Narrows Bridge, in that civil engineers studied it and learned from the mistake. What happened there is unlikely to happen again in any newer building, because they learned what not to do from it..
posted by Chocolate Pickle at 4:16 PM on December 10, 2010 [1 favorite]
I should mention that in the case of the Hancock tower, it was the mounts which failed. The glass panes themselves didn't break until they hit the street.
posted by Chocolate Pickle at 4:19 PM on December 10, 2010
posted by Chocolate Pickle at 4:19 PM on December 10, 2010
Response by poster: Yeah, I was wondering because, during storms, there are occasionally parts of balconies and so on on the ground. And yesterday, an individual ended their life via defenestration and landed in the daycare playground. While this was horrifying and traumatic enough, it did make me wonder about the stability of the glass overhang and walls, especially if there was a storm, earthquake or even just someone tossing something off the balconies above. I wondered if, over time, the glass walls and so on would deteriorate and whether anyone checks on that.
SSG, thank you for explaining about the inspected trades bit.
posted by acoutu at 10:35 PM on December 10, 2010
SSG, thank you for explaining about the inspected trades bit.
posted by acoutu at 10:35 PM on December 10, 2010
This thread is closed to new comments.
posted by theodolite at 11:52 AM on December 10, 2010 [3 favorites]