Volume 13, Issue 7 - September 2012
Preparing for The Worst
For doors and windows located in hurricane-prone coastal areas, there are three key considerations: structural resistance to high wind pressures, resistance to impact from wind-borne debris and water penetration from wind-driven torrential rains.
While doors and windows can be configured to stand up well to these onslaughts, even the strongest, tightest and most impervious product will not deliver the intended protection if the quality of its installation does not equally address the extreme conditions for which it was designed.
So, as construction and hurricane seasons begin to overlap, we are reminded of two industry standards that address exactly this concern for doors and windows installed with mounting flanges intended for use in wood frame construction (the most common installation configuration).
Hurricane-resistant installation must include the appropriate selection and use of anchoring devices, installation accessories, flashing and sealants.
Assuming structural integrity, uncontrolled water penetration has been cited as a major failure mode for door and window installations exposed to hurricane conditions. To address this concern, the mounting flange must join together with the exterior facing material, sheathing and the water-resistive barrier (WRB) to form a unified, fully integrated “drainage plane.” Therefore, the ultimate solution for hurricane water penetration lies in a robust integration of the door or window with the drainage plane.
Installation Basics: ASTM E2112
AAMA 2400, Standard Practice for Installation of Windows with a Mounting Flange in Open Stud Frame Construction for Low Wind/Water Exposure, an extension of ASTM E2112, covers the installation of new windows with integral mounting flanges or fins in a typical new construction stud wall. (AAMA 2410, Standard Practice for Installation of Windows with an Exterior Flush Fin Over an Existing Window Frame provides similar guidelines for the installation of replacement windows.)
But hurricane-resistant installation must take the basic methods outlined in these standards and improve upon them. In response to the Florida Building Commission’s 2004 request for more robust installation practices in hurricane zones, AAMA joined forces with the Window and Door Manufacturers Association (WDMA) and the Fenestration Manufacturers Association (FMA), to develop enhanced guidelines for the specific wall types typically found in the coastal southeast region.
Ken Brenden serves as technical services manager for the American Architectural Manufacturers Association in Schaumburg, Ill.