AAMA Supporting New Hurricane Research Effort

July 1, 2007

A pioneering effort to measure wind-driven rain at structural height during hurricane landfall will be undertaken by wind engineering researchers at the University of Florida, with key funding underwritten by the American Architectural Manufacturers Association. The association is donating $60,000 to purchase a precipitation imaging probe designed to capture high-resolution measurements of rainfall intensity.

Dr. Forrest Masters, assistant professor of civil and coastal engineering, will deploy the instrument on a specially designed rugged tower that will be moved into place in the hours before landfall to capture the worst conditions of a hurricane. “We are exceptionally eager to get the instrument in the field as soon as it is commissioned,” notes Masters. Using real-time cellular and satellite uplinks, data from the device will be available in real-time to National Oceanic and Atmospheric Administration meteorologists and state and federal emergency managers.

“Beyond the ability of a building to physically withstand hurricane winds, water intrusion through windows, doors and walls remains a recurring issue,” notes John Lewis, AAMA technical director. “Although most residential and commercial buildings built to recent codes will survive structurally, rain penetration often causes significant interior damage, occupant displacement, business interruption and extensive restoration expenses. Code officials, architects and manufacturers of exterior building products are questioning the real-world effectiveness of water intrusion test standards under hurricane conditions as referenced by modern building codes.”

“At the urging of the Florida Building Commission, the AAMA Southeast Region is currently developing a voluntary specification for rating the severe wind-driven rain resistance of windows, doors and unit skylights,” continues Lewis. “Instead of the usual pass/fail measurements, this AAMA specification applies a spectrum of pulsating pressure and rain loads and determines how well a product performs in severe wind-driven rain. The research, underway at the University of Florida, will further the value of the AAMA specification by quantifying hurricane-driven rain and its effects on residential and light commercial construction.”

“Approval was expedited through AAMA’s board of directors during its national summer conference so that a critical measuring instrument would be in place for recording hurricanes in the 2007 season,” says Rich Walker, AAMA president and CEO.

Data from the devices collected during this and upcoming Atlantic hurricane seasons will be used to establish a catalog of “wind-driven rain scenarios” for different storm intensities affecting various terrains. The information will be used to calibrate the rain field produced by the University of Florida’s mobile windstorm simulator to recreate hurricane-force winds and wind-driven rain at sufficient scale to test low-rise components and cladding systems. Utilizing four 700 hp Detroit Diesel engines and hydraulic drive units to power eight 54-inch vane axial fans, the apparatus will produce hurricane force winds and wind-driven rain at its 10-by-10-foot exit.

Actual full-size structural mockups will be evaluated in realistic hurricane conditions, according to Lewis. “The University of Florida will collaborate with industry and building code partners to evaluate the performance of the windows, doors and wall assemblies, including service penetrations, wall siding, finishes and vents. The simulator—calibrated to recreate actually recorded wind-driven rain scenarios—will be able to provide a realistic evaluation of building products and test methods intended for hurricane-prone regions, as outlined in the AAMA specification to be finalized based upon results from the study.”

All research will be coordinated with established program partners such as AAMA, as well as Florida building code officials. “Finally, window, door and wall systems will be evaluated in the prescribed conditions, providing greater certitude in the products that are tested in compliance with AAMA specifications,” concludes Lewis.