Author |
Message |
Joel McKellar, Assoc. AIA, LEED AP Senior Member Username: joelmckellar
Post Number: 17 Registered: 02-2006
| Posted on Tuesday, February 12, 2008 - 05:18 pm: | |
What should I be looking for when specifying sunshades for curtain walls? I've found a few companies that integrate sunshades into their systems (Kawneer, EFCO, Wasau, and YKK). I'm no engineer, but looking at the details none seem extremely secured to the walls. Are there any performance standards to reference? Details to watch out for? Thanks, Joel |
Phil Kabza Senior Member Username: phil_kabza
Post Number: 303 Registered: 12-2002
| Posted on Saturday, February 16, 2008 - 10:21 pm: | |
The obvious advantage of specifying a sunshade that is integrated with a curtain wall system is the comprehensive engineering. Otherwise, you'd have to engineer attachment to the structure, and deal with wind loading and seismic design loading - complex, and not something your project structural engineer looks forward to. The other challenge for stick built sunshades is how they are to attach to the building structure. They're going to be a air- and moisture-barrier penetration, as well as a thermal envelope anomaly. Plus a great opportunity for bi-metallic corrosion. I guess you can tell how enthusiastic I am about these ... |
Anonymous
| Posted on Saturday, February 16, 2008 - 11:23 pm: | |
Uneven shading or shadows on glass or glazing can lead to uneven temperatures of the glass which in turn can lead to spontaneous thermal breakage. Shutters or screens or canopies have to be properly designed to avoid these uneven thermal conditions on the curtain wall. |
Bill Coady CSI, CCPR Intermediate Member Username: billcoady
Post Number: 4 Registered: 06-2006
| Posted on Monday, February 25, 2008 - 07:37 pm: | |
I'd like to add to "anonymous'" statement about thermal stresses on the glass. While the shutters/screens/canopies should be designed properly of course, it is important that the glass be analyzed for thermal stresses to determine if it needs to be heat treated. There are a few rules of thumb about when to heat treat for thermal stress but it is better to be safe and have an analysis completed. Most fabricators and glass manufacturers will do this at no charge on a project specific basis. |
Steven Bruneel, AIA, CSI-CDT, LEED-AP Senior Member Username: redseca2
Post Number: 84 Registered: 12-2006
| Posted on Tuesday, February 26, 2008 - 12:59 pm: | |
I am familiar with an un-named large renovation project where sunshades were added to the exterior to allow the existing single monolithic pane glass to remain while meeting modern energy efficiency requirements. The issue of spontaeous thermal breakage was not considered by the design team and only came up during job walks by design-assist bidders. Now the project has replacement glass in the scope and has kept the sunshades, more as a decorative feature than originally intended however. |
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