Energy Efficient Windows
After reading the post on Property Conservation, it reminded me of a commercial I saw on TV. The ad was for energy efficient windows that could be struck forcefully with an object and not break. It appeared that the object used was similiar to a tool we would use to take a window. Anyone come across these windows in an incident and how did you address the problem if you were not able to just open the window? Thanks in advance!
I once almost fell off a ladder when trying to take out a window...it was made of plexiglass. I had a halligan bar with me, and when I hit the window, it just bounced back at me. If it weren't for a leg lock, I would have taken the express ride down to ground level! :eek: Another Brother on my Department lost his two front teeth when trying to take out a plexiglas window....the tool he had bounced back, too. :eek: :eek:
Both of these fires happened in residential dwellings. I suppose you can always take the saw and cut the area around the window out, if need be!
If any of you are seeing the proliferation of lightweight "C"-Joist construction in your areas, take note.
As one of the few departments who allow out Truck Chauffers to vent windows with the tip of the aerial, there is some concern about twisting and/or deforming the framing the windows are attached to.
Many of these buildings now have brick facades or several layers of a Stucco like finish. Should the C-Joist members twist or pull away from the exterior wall, there could be a localized collapse.
Building codes just don't take fire into account, only fire prevention. After seeing these buildings getting built, I almost miss LW Truss construction.
Couple of thoughts....
Don't forget, most of these new windows are the tilt type. If you open them a little and hit the tilt mechanism, they will tilt in all the way.
Most of them, if you grab the two sides of the window and raise one and lower other, they will come out completely. Repeat with top and you have a completely opened window. Of course, have to be inside.
If they don't come out, tilt lower window, move it down as far as it goes and then do same with upper. This should give you more than 3/4 of the window opening.
I have some of the "unbreakable" windows on my house. I question the claim, because the demo that the salesman used was 1/2 or 1/4 of full size. Simple physics tells you that the smaller the surface of glass, the stronger it is. I wonder if the picture window I have would take the same beating. Needless to say, I haven't tested it.
[ 09-10-2001: Message edited by: no_name_FF ]
"Engineered construction techniques" should be a term that all firefighters are familiar with. Remember, this is what brought on the explosion of truss roofs, c-joist construction and other pitfalls we haven't yet suffered.
Some of the "engineered lumber" includes replacing a 2x8 or 2x10 or 2x12 with 2 2x4 on each end with a compressed board in between (usually 1/2 inch thickness). This is supposed to be as strong as the board it replaces, however, a 1/2 glueboard is gonna burn a lot quicker than a solid 2-by piece of lumber. Think of a basement fire with the whole first floor supported by these beams....
Does anyone know of any data that I can get my hands on regarding the burn rate of these products?
Is lightweight "C" Joist the new metal studs??? Haven't heard the term before, but the description of how they'd act sounds right...
The C Joists look just like tthe metal studs we're familiar with, just a heavier gauge. Only now they are used as bearing and non-bearing members, floor joists, roof joists and everywhere else wood was once used.
They are "Cold Formed Steel" so they are not tempered and fail quickly under heat. On top of all this, 90% of the construction in my area has poured 4" slabs on the floors and roof.
I have seen any number of connections used. Spot welds, sheet metal screws and where they connect to a masonary wall, no fasteners or fire-cuts. While the industry has embraced the latest in "Engineered Construction" the laborers who put these buildings together have NO concept of what they're doing.
Spans, bracing, doubling, connecting, the list goes on and on. It seems like every crew I've inspected is using a different method.
Imagine a six story apartment building with a brick facade. The framing is nothing but the above type of steel, held together with 1/2" screws. All the floors are concrete as well as the roof. There's no fire but the local sanitation truck backs into the corner of the building while picking up a dumpster.
Now you figure out how this building will react.
These C-Joists described by E229lt are as bad as he says they are. They're just 12 guage galvanized steel, with reliefs punched for pipes and cable, and usually set on 20 inch centers - a disaster waiting to happen.
Also called "Speed Beams" property developers, building owners, and construction managers love them.
They can be delivered precut or very easily cut to size on site, and are much cheaper than the traditional steel beams that must be cut to size, drilled, and dressed off site and then delivered in time sensitive sequence to the job.
NYC's Union Ironworkers (Local 40 and 580) hate them because they've lost work. Speed beams have replaced the steel beams and columns they would normally raise, and because speed beams are technically studs they're carpenters work. Labor costs and savings therefore also factor in to the use and desirability of these speed beams.
There is a wide variety of ceilings that can be hung or screwed to the bottom side of these speed beams. Sheet rock is most often used, and that depends on code, but the bottom line is that even if they're covered and even if they're "properly" erected and fastened - they will easily fail from heat.
As E229lt points out, 4" concrete slabs are poured atop. After 20 guage decking is shook out over the speed beams, a lightweight air-entrained concrete is pumped up to make the floors AND roof. No rebar, just 6X6 mesh. No torsioning cables, just fiberglass fibers.
The speed beams used for window jambs are usually just held in by two #8 sheet metal screws - one at the top and one at the bottom. Sometimes the speed beams used for walls and window framing are only 18 guage.
I'd hate to see a truckie use the stick to take out windows here. Even the boom trucks delivering sheet rock, tubs, and water heaters have taken down whole walls with just a bump here or there.
PS: Stay out of the "safe" stairways. Stair stringers and platforms get welded or bolted to these speed beams too ...
Generally speaking, brick facades are very strong in compression, but have very little tensile strength, so the situations described above by E229lt, where C-Joists are used in place of traditional wood members for window framing in buildings with brick facades, are good candidates for collapse.
A number of the buildings in my city have new plexi-glas windows or even tougher ones made of lexan. We had a BIG fire at one of the buildings under construction and discovered that the picture windows couldn't be broken. The latest I heard was to use the saw.
My first experience with Lexan was the 7/91 subway derailment under Union Square near 14th Street. In a few situations the NYPD and FDNY needed K-12s to cut open the cars. It wasn't the stainless steel or high carbon steel that put up the most fight - it was the Lexan that the MTA uses for subway car windows. The kerf made by the saw melted back together! Their solution was to make several small cuts instead of one long continuous one, and then they went back and cut between the small cuts. I'm not saying you have to do this for residential sash, but Lexan and plexi-glass does make for creative thinking. Does anyone know about the burn rates that no name asked about?
I'm wondering what would happen if you released some CO2 from an extinguisher on the window. Then hit it with a tool. Would it shatter? Haven't tried it. Has anyone?? :)
[ 10-01-2001: Message edited by: NY Smokey ]
I definitely remember an instructor telling me that you could break these type windows using a CO2 extinguisher and a pick head axe. I have not seen it demonstrated or tried it myself however. I would be interested to know if this really works on the fireground.
During a class once the instructor was about to talk on using CO2 and an axe to open up lexan windows... one of our new guys didn't understand what he was trying to convey and he made the comment "what, point the base of the extinguisher at the window and knock the head off?". The class busted up, since then he's had the nickname "rocketman".
:D :rolleyes: :D
Stay Safe, Frank
We had a fire in the top floor of an old renovated mill building. The steel pull-chain hopper windows with lots of mutton bars and small lights of thin glass had all been replaced with energy efficent units.
We were sent to the roof to take the windows. I could reach down to them with my pike pole, but no matter how hard I hit them all I did was bounce. Plexi-glass?
I saw smoke coming from one window that had started to bubble and sag. I was able to use my pike pole to open it up, but unlike glass which just breaks, the whole piece of plexi-glass came out and instead of falling down to the ground the whole piece sailed up in the heat plume for a second or two and then seemed to sail halfway down the block in the smoke cloud I had unleashed.
Luckily, it didn't hit anyone or anything!
We looked at it afterwards. It was 3/8 inch Lexan.