FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

11 Designing the builDing envelope Volume II
Figure 11-14.
House in Puerto Rico with
metal jalousie louvers
11.3.1.4 Water Infltration
Heavy rain accompanied by high winds can cause wind-driven
water infltration. Te magnitude of the problem increases with
wind speed. Leakage can occur at the glazing/frame interface,
the frame itself, or between the frame and wall. When the basic
wind speed is greater than 150 mph, 9 because of the very high
design wind pressures and numerous opportunities for leakage
path development, some leakage should be anticipated when
the design wind speed conditions are approached.
A design option that partially addresses this problem is to
specify a strip of water-resistant material, such as tile, along
walls that have a large amount of glazing instead of extending
the carpeting to the wall. During a storm, towels can be placed
along the strip to absorb water infltration. Tese actions can
help protect carpets from water damage.
It is recommended that design professionals specify that window
and skylight assemblies comply with AAMA 520. AAMA 520
has 10 performance levels. Te level that is commensurate with
the project location should be specifed.
Te successful integration of windows into exterior walls to
protect against water infltration is a challenge. To the extent
possible, when detailing the interface between the wall and
note
Laboratory research at the
University of Florida indicates
that windows with compression
seals (i.e., awning and casement
windows) are generally more
resistant to wind-driven water
infltration than windows with
sliding seals (i.e., hung and
horizontal sliding windows)
(Lopez et al. 2011).
Cross referenCe
For guidance on window
installation, see:
FMA/AAMA 100
FMA/AAMA 200
9 The 150-mph basic wind speed is based on ASCE 7-10, Risk Category II buildings. If ASCE 7-05 or an earlier version is used, the
equivalent wind speed trigger is 120 mph.
11-14 COASTAL CONSTRUCTION MANUAL