Recommended window class
Recommended window class
(OP)
I have been asked by an architect to take a look at some backup steel for mullions for a large windows and doors. The project is a church, mean roof height of 42' and the steeple goes up to 65'. I noticed that the specs called out AW40 class window, which after research appears to be more appropriate for high raises. The window manufacturer indicated that he was unable to make the AW grade but "meet the grade of 40 and used that grade for the complete assembly including the mulls". I asked him what wind pressure he was using and he said that his wind speed works out to be about 153 mph. In my mind he should design for 90 mph, the required speed in the area. He calculated a wind pressure of 37.5 psf which seems reasonable to me.
Also, looking at AAMA performance class overview, I think the spec should have called out CW class.
I am looking for some input here as I am not fully familiar with all these window designations. Would a change to CW class with use of a minimum wind speed of 90 mph be the right thing to do here?
Thanks,
Also, looking at AAMA performance class overview, I think the spec should have called out CW class.
I am looking for some input here as I am not fully familiar with all these window designations. Would a change to CW class with use of a minimum wind speed of 90 mph be the right thing to do here?
Thanks,






RE: Recommended window class
AAMA/WDMA/CSA 101/I.S.2/A440-05
Standard/Specification for Windows, Doors, and Unit Skylights
The 1997 version of the standard is even better, so read it as well.
Manufacturers will say that they can do most anything. Salesmen will say similar. Unless they have documented evidence by an independent testing laboratory of meeting a written, accepted standard, don't accept it.