DWM - 2006 - September

Volume 7, Issue 8 - September 2006

FMA insights

The Wall of Wind
Testing for the World in Which We Live
by Bruce Jasewic

In a Spring 2005 proposal to the National Science Foundation (NSF), engineer and hurricane researcher Dr. Forrest Masters contended that the current trends of reduced vertical wind shear and elevated sea-surface temperatures in the North Atlantic will persist for several decades. He also announced with the increased likelihood of hurricanes and the rising coastal population, the possibility of a major hurricane striking a large population center in the next 30 years emerges as a near certainty. Since Dr. Masters’s proposal, Hurricanes Katrina, Rita and other lesser storms have ravaged the Gulf Coast.

Dr. Masters is an assistant professor of Civil and Environmental Engineering at Florida International University, directs the Laboratory for Wind Engineering Research at the International Hurricane Research Center and is the lead researcher for the Wall of Wind Project (for more info, see July-August DWM, page 53).

Industry: Pay Attention
Any construction industry member or building owner in a storm-prone area should take a keen interest in this project. The main goal is to focus on the disaster risk key issue identified by the National Science Foundation’s Partnership for Advancing Technology in Housing (NSF-PATH) program with emphasis on affordability and durability. To accomplish this goal, the project will use a new testing device, the Wall of Wind, to replicate the authentic, “real-world” dynamics of wind and rain on a full-scale structure.

Dr. Masters’s first device is really more like a Junior Wall of Wind. But even Junior looks like something from television’s Monster Garage. Masters started with a dual axle trailer—the type used to transport tractors. To the trailer, he added an 8-foot-square, 14-foot-high tower fashioned from steel tubing. Inside this tower are two 496-cubic-inch engines, mounted one above the other. Attached to the crankshaft of each engine are two 84-inch three-blade counter-rotating propellers. Junior is attached to a test chamber with a wall and roof section built into the opposite end. Just past the propellers are a series of nozzles to simulate rainfall.

A separate cargo trailer houses computers, data acquisition equipment and engine controls. This equipment is attached to load cells, orientation sensors, anemometers and high-speed cameras. Inside the trailer, the operator can control wind speed and water flow independently while the test is in progress. The system records all this data, along with pictures from the high-speed cameras. The interior of the wall and roof section in the test chamber is accessible from the outside during the test. Inside this test wall sits more equipment that collects and measures the amount of water penetrating the test sample mounted in the wall. With all this equipment, the operator can test the effects of varying wind speed and rain on a test specimen accurately and record the results digitally. Different designs of the same type of product can be tested, the data can be compared, and the best design can be chosen based on true storm conditions.

I spent a day with Dr. Masters and his group, observing them as they prepared Junior to test different types of soffits. I saw wind speeds up to 120 mph and water flow up to 35 inches per hour. During these tests, any water that penetrated the installation was photographed with a high-speed movie camera connected to a computer that can view data in real time, collect it, measure it and record it. I see many opportunities for fenestration manufacturers to use testing like this to improve product performance and to provide their customers with products that will protect their homes.

When finished, the full-grown Wall of Wind will be similar to Junior, only larger. It will have six or more engines driving propellers. Its purpose will be to simulate true hurricane conditions on full-size structures rather than on product samples. Masters’s goal is to test buildings as integrated structures rather than as collections of components. With the Wall of Wind, Masters will be able to test not only doors, windows, soffits and shingles but also measure how well these components interact in making a safe, well-built home.

Additional Research
In addition to his Wall of Wind, Dr. Masters is a principal participant in the Florida Coastal Monitoring Program. The goal of the program is to measure both the wind velocity at ground level and the wind forces affecting the building envelope. Program researchers will then use that data to evaluate the effectiveness of wind-resistant structural retrofits. As part of their efforts to gather the best data available, program researchers build special towers that measure and record storm conditions. Whenever the researchers see that a hurricane will make landfall, they chase it down, erect their towers and acquire storm data straight from the best possible source: the storm itself. Dr. Masters uses this valuable data to simulate actual storm conditions with his Wall of Wind.

Note: This project will be discussed in further detail in DWM magazine’s October issue.

Bruce Jasewic serves as director of engineering for WinDoor Inc. in Orlando, and is a member of the board of directors of the Fenestration Manufacturers Association.