Armed and Ready
Industry Resources Address Hurricane Mitigation
by Rich Walker
The 2011 hurricane season spanned June to November, Arlene to Rina. Between
hurricanes, the United States was hammered with tropical storms and tornadoes.
To mitigate damage to occupants and structures, the American Architectural
Manufacturers Association (AAMA) offers voluntary specifications to help
fenestration products, including architectural metal framed products such
as windows, curtainwall and skylights, address severe wind-driven rain
and the impact of wind-borne debris.
Doors, windows and unit skylights are typically selected based on local
or state building code requirements. The primary consideration is structural
integrity, to keep the unit intact and prevent the pressure of high-velocity
wind from entering the building and causing catastrophic structural failure
or life safety concerns. In tropical storms and hurricane wind-driven
rain conditions, the product selected to meet the code requirements may
experience water penetration when these extraordinary conditions exceed
the performance rating for water penetration resistance.
AAMA 506-08 “Voluntary Specifications for Impact and Cycle Testing of
Fenestration Products,” is cited in the 2010 Florida Building Code and
in the 2012 International Residential Code. AAMA 506 was updated and published
in July 2011 and uses existing ASTM test methods to qualify doors, windows
and skylights as impact resistant. It includes all framing materials,
including aluminum and other metals, covered by the standards and specifications
listed in this document.
In addition to AAMA 506-11, AAMA 520-09 “Voluntary Specification for Rating
the Severe Wind-Driven Rain Resistance of Windows, Doors and Unit Skylights,”
rates a product’s ability to resist water penetration during the most
severe weather events. This voluntary specification is based on a rapidly
pulsed pressure differential method, recognizing that conditions encountered
during tropical storms, hurricanes or severe thunderstorms are not static.
The rating obtained from performing the testing cited in this specification
is intended to exceed the water penetration resistance levels derived
from other testing specifications (e.g., AAMA/WDMA/CSA 101/I.S.2/A440)
currently in use.
In the aftermath of tropical storms and hurricanes, questions were raised
by some residents who experienced wind-driven rain leaking through or
around their doors and windows that otherwise remained unbroken and structurally
intact during these extraordinary events. Rain driven by high winds may
enter the wall cavity of a home or building at any number of points, some
well above the location at which they appear, such as the attic or roof,
soffit or wall penetrations, such as exhaust fans. Running down the inside
of the wall, it may exit the wall around the rough opening at a door or
Even though the window was properly anchored for structural integrity,
it may leak if not correctly flashed and sealed. Doors and windows that
are not installed plumb, square and in plane will not close properly.
This leaves gaps, which, though very small, are sufficient to admit rain
when driven by storm-force winds. The age of the door or window, condition
of seals and weatherstripping, and other maintenance matters such as clogged
drainage/weep holes, can contribute to leaks appearing during wind-driven
rain conditions. All doors and windows should be regularly inspected for
damage or wear, and repaired as needed.
“It also is important
to review product limitations with property owners and to remind occupants
of necessary precautions in the event of wind-driven rain and hurricane
conditions, as some amount of water penetration during an extreme weather
situation is possible.”
Architects may find themselves more frequently addressing these concerns
and code requirements for those living and working in areas prone to severe
windstorm events. In addition to specifying proper performance and installation
of fenestration products, it also is important to review product limitations
with property owners and to remind occupants of necessary precautions
in the event of wind-driven rain and hurricane conditions, as some amount
of water penetration during an extreme weather situation is possible.
Following wind-driven rain events, some may mistakenly think that water
penetration is a defect of the product. In most cases, this is not true.
Doors, windows and skylights tested to meet AAMA 520-09 are provided with
ten performance levels. During the testing, pulsating pressure is applied
for 300 cycles with water spraying in accordance with the specified performance
level. Water penetration to the interior is monitored throughout the test.
At the test’s conclusion, any water that penetrates the innermost plane
of the product, passes through the product mainframe, or overflows the
sill is collected and weighed. Products that pass the test and meet AAMA
520-09 are allowed no more than 15 ml, or approximately 0.5 ounces (per
meter [39 3/8 inches] of sill width), of water into the interior under
these extreme conditions.
Architects can use AAMA’s online Certified Products Directory to identify
hurricane impact-resistant doors, windows and skylights. The site also
features an online Publication Store where hurricane-related documents
can be purchased, and an online directory of AAMA-accredited labs to perform
Rich Walker is the president and chief executive officer of the
American Architectural Manufacturers Association in Schaumburg, Ill.
Architects' Guide to Glass & Metal
© 2011 Copyright Key Communications Inc. All rights reserved.
No reproduction of any type without expressed written permission.