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It's all about Windows!
By: Robert Holcombe
Windows with Dual Finishes10:00AM on Thu 23 Jul 2009
If you ask our customers “Why don’t you ask for more projects quoted in dual finishes?” they might say “I never see it specified”.
If you ask architects “Why don’t you specify more dual finish projects?” they might say “I didn’t know I could get it”.
Some products are limited to one finish because they are simply single extrusions. Other products like Trifab 451T are limited to a single finish because of their “pour and de-bridge” type of thermal break. Thermally broken products that use a polyamide style thermal break like the new AA3350 Single and Double Hung window can join two separately finished interior and exterior aluminum extrusions together.
Think about it…then let me know your thoughts.
Keeping up with Window Performance Standards7:46AM on Wed 08 Jul 2009
WOW…. Keeping up with the current performance standard for windows is like alphabet soup. Let’s see… you’ve got AAMA 101, WDMA I.S.2, CSA 440 all rolled up into something now called NAFS. Not to mention the various versions like -97, -01, -05 and now NAFS-08. Then throw in what used to be C and HC and change that to CW with a little AW sprinkled on for extra flavor. Let’s see if we can put some clarity around just a little of this.
Early on, the Architectural Aluminum Manufactures Association (AAMA) produced a performance standard for the “Voluntary Specifications for Aluminum Prime Windows”. (Key words- Aluminum Windows) Later on the vinyl folks felt left out and AAMA became the American Architectural Manufacturers Association (still AAMA though). If that wasn’t enough, in 1997, the wood window people wanted a piece of the action too. So for years now AAMA 101 has represented the performance standard for our industry in the good old US of A.
But now let’s don’t forget our neighbors to the north, the Canadian Standards Association or better known as CSA – International. Just think, we can become one big happy North American family called oddly enough the North American Fenestration Standard (NAFS) and get all the bases covered. Believe it or not this could actually be a good thing as Canada is expected to fully adapt NAFS in 2010.
As far as the window classifications go just try to remember that what used to be “C” for Commercial and “HC” for Heavy Commercial is now combined into “CW” for Commercial Window. The performance bar was raised a little for Commercial and lowered a little for Heavy Commercial but no real harm done. The higher performing Architectural Window or “AW” class is still here so don’t get your hopes up. Clear as mud huh! Is this as confusing for you as it is for me? I'd love to hear from you.
So…. God bless us all. Let’s eat soup!
Thermal Continuity in Window Design8:52AM on Tue 07 Jul 2009
I’ve always hated drinking coffee through a lid. It’s too much like a “sippy cup”. But as I burned the skin off my upper lip this morning, I realized just how important thermal continuity is to the entire coffee mug system. Thermal continuity is important to a lot of things, just as it is with Kawneer’s new single- and double-hung window, the AA®3350 ISOPORT® Window.
You can position the thermal break in many products almost anywhere you want and get decent results. With Casement Windows for example, the ones that open and close like a door, the operable sash is nested in its frame, making it quite easy to align the thermal breaks and get good performance. Single and double hung windows, where the top sash is in a different plane than the bottom, is an entirely different story. There’s two questions here, “How do you maintain a consistent thermal break from the top to the bottom?”, and “How do you keep the thermal break in the two sashes aligned with the thermal break in the frame? “ In fancier words - How do you maintain the thermal continuity? It’s simple. It’s all in the unique thermal break design of the AA®3350.
Thermally broken aluminum windows have been around for a long time. Some use a method called “P&D” or “pour and de-bridge”. With P&D, a liquid resin is “poured” into an extruded channel, the resin quickly hardens and then the back of the channel is ripped out or “de-bridged”. This splits the aluminum extrusion into two halves joined by the thermal break. (A typical pour and de-bridge extrusion assembly is shown at left - click image to enlarge.) Other thermal products, like the AA3350, are designed with stiff plastic strips or “dog bones” clamped between two individual aluminum extrusions. This method allows much more design flexibility.
When you look at the outside frame of the AA3350, the first thing you notice is the large black plastic (actually polyamide) thermal break. (View of AA3350 polyamide thermal break used in frame jamb members shown at right - click image to enlarge.) Because this type of thermal break is not nearly as limited as P&D, we can design it large enough to maintain alignment or continuity with the thermal break in the top and bottom sash. A closer look at the unusual thermal break design where the top at bottom sash meet in the middle shows how the thermal continuity is maintained from one plane to the other. In the end, everything exposed to the weather on the outside is consistently separated from the inside.
Note how the thermal continuity is maintained between the frame and sash members .
So there… problem solved. The next time you burn your upper lip on an aluminum window look for thermal continuity. Now, I'd love to hear from you so, be sure to share your thoughts and comments.