Why a Hurricane-Rated Window Can Still Fail NYC Building Code

Your replacement windows are rated to withstand a 200 mph wind — so how can an engineer reject them at a site where the design wind speed is only 115 mph? We recently worked through exactly this situation on a high-rise residential building in New York City. The answer surprises contractors, window dealers, and even many engineers: the window wasn't failing on strength. It was failing on stiffness — the frame deflection limit of NYC Building Code Section 2403.3 (mirrored in IBC 2403.3 nationwide).