Volume 9, Issue 6 - June 2008

run forrest, run

A UF Research Team Heads Straight to the Storm to Study Hurricane Effects on Doors and Windows
by Ellen Rogers

When hurricane season rolls around most Floridians prefer to run away from the storm, but not Forrest Masters. Masters, Ph.D., an assistant professor of civil and coastal engineering at the University of Florida (UF) in Gainesville, prefers running toward the storms. And the fenestration industry is joining this journey with him.

Masters is heading up a research project designed to take actual hurricane data and replicate it in a laboratory setting. Once complete, the results will offer the fenestration industry input on new testing methodologies for evaluating water infiltration of doors and windows.

A UF graduate, Masters has been working for the university since 2006.

“As an undergraduate I was involved in UF’s hurricane research program. I later went on to a wind-engineering focus in Miami at Florida International University. But when I was presented with the chance to come back here, it was an opportunity I couldn’t pass up,” he says. “I was born a Gator.” 

But there’s more to Masters than his Gator pride. As a recognized hurricane expert, he’s passionate about the research he does and finding ways to reduce the loss of life and property.

“I found my passion for this work when I started traveling into hurricanes and seeing first-hand how communities can be affected,” says Masters, who has been in the field setting up instrumentation just hours before hurricanes make landfall, including 19 named storms since 1999. The purpose of doing so is to collect field measurements and to monitor the pressures on single-family homes. 

Masters says those early efforts didn’t see much action until the 2004-2005 hurricane seasons. Now, armed with an abundance of information, Masters is working with a number of industry groups, such as door and window manufacturers and test labs. His efforts have earned national coverage from such media sources as Good Morning America and CNN.

“At the core of this program, we think the industry knows more about its products and installations than anybody else,” says Masters. “And we know more about hurricanes and hurricane wind effects, so it was a natural fit to bring both groups together to tackle these issues.”

Hurricane Simulation
To create the true hurricane forces, a research team, consisting of Masters and a number of graduate and undergraduate engineering students, constructed a massive simulator.

The simulator includes eight mammoth-sized fans that push approximately 900,000 CFM (a typical residential air conditioner generates about 1,000 CFM) powered by four diesel engines (that use about four gallons of fuel a minute) that collectively produce 2,800 horsepower. The simulator is designed to force winds of up to 135 to 140 miles per hour upon a wall mock-up. High-pressure water jets also simulate wind-driven rain of up to 35 inches per hour.

While the program has been moving forward for about 18 months, the team is just beginning the actual research phase.

“We’ve been in the fabrication phase and now we’re moving into the research,” Masters says. “The first projects relate to the fenestration wall research.” (Editor’s note: at the time of this article the testing phase was just starting). Tests, conducted in accordance with ASTM E2268-04 and ASTM E1105-05, will be done on a variety of aluminum and vinyl window types including fixed, double- and single-hung, awning, casement and horizontal sliders.

“The majority of the fenestration work will be finished here by the end of July,” Masters says. “We’re looking at installation variations and trying to optimize installation. We’re also comparing different test methods.”

The most critical research element is the project’s whole-system testing aspect. 

“We are trying to shift the mindset from product-specific performance to system performance,” says Masters. “Whole-system testing is the basis of this experimental work. So, instead of evaluating a window we’re evaluating a wall; we’re evaluating a window installed a certain way in a wall system and seeing how the whole unit performs.”

Group Effort
To help guide the team’s efforts a task force was assembled that includes fenestration manufacturers, such as General Aluminum and Jeld-Wen, architects, homebuilders, engineers, code officials and representatives from test labs and the insurance industry. Masters says input from the task force is an integral component of the project.

“If we’re remembered for anything I hope it’s that we brought all the different stakeholder groups together to tackle a problem,” says Masters. “We’ve been able to put [them all together] in the same room and have meaningful conversations. It’s those conversations that are driving this research.” 

The Fenestration Manufacturers Association (FMA) is just one of the industry groups supporting the research project. The FMA/AAMA 100 and FMA/AAMA 200 protocols for best management practices of installation into wood and concrete masonry units will both be used as part of UF’s test regimen.“

[We expect] this will provide the fenestration industry the opportunity to observe an industry consensus window installation into the wall system and hopefully scored on the overall performance of the wall as well as the window,” says Dick Wilhelm, FMA executive director. “The second most important aspect to our industry is Dr. Masters’ validation of the current air and water intrusion testing of standards [that have been] used in the industry for years. The results could have a significant impact on fenestration manufacturers and how they do business in Florida in the future.”

Freddie Davis Cole, national sales manager for General Aluminum Windows and president of FMA, says the research project is extremely important.

“It appears to be the first time we will have peer-reviewed, verifiable research that we can use for designing, testing, installing and integrating fenestration products into the wall system,” says Cole. “This work will be of particular importance to our door manufacturers because it has been brought to light in the state of Florida that while windows are tested for structural, water/air and forced entry resistance, exterior doors are not.”

Likewise, the American Architectural Manufacturers Association (AAMA) has also seen the importance of supporting this research effort.

“The goal of this research is to develop a realistic evaluation protocol and test methods for building products installed in hurricane-prone regions,” says Rich Walker, AAMA president and chief executive officer. “While the majority of residential and light commercial properties built in compliance with current codes withstand hurricane winds, water intrusion through the envelope under these high wind conditions has neither been thoroughly tested nor simulated. When rain penetrates the building envelope, it can result in interior property damage, occupant displacement, business interruption and extensive restoration expenses.” Walker says the research will result in accurate and reliable testing that simulates real-world hurricane conditions. “It will protect more people from injury and property from water and wind damage,” Walker adds.

Industry Support
Masters says the Florida Building Commission has been looking to the industry for many years to help tackle the hurricane-related issues that affect the state of Florida. So when it came to [UF] developing its full-scale technologies it seemed a natural mesh to rely on the industry as well. As Masters explains, it’s the needs of the industry that are driving the project. 

“I think we [the research team] approach these experiments with a fair amount of humility and we need the industry to help steer us down the right path and to make sure we’re testing systems that are actually used and installed in a manner that’s realistic,” says Masters, who adds that industry companies have been extremely helpful. 

In addition to working with door and window manufacturers, the team is also working closely with test labs including Architectural Testing Inc. (ATI) and Certified Test Labs (CTL). 

“We’re working with the test labs so we can better design our lab set-up for testing and comparison purposes,” says Masters. “Also, they have a wealth of experience in seeing products and how they perform, so they can help us narrow the chase in getting to the right experimental design.”

Jim Blakely, vice president of CTL in Orlando, Fla., says bringing all of the stakeholders together to be a part of the research project will be beneficial in finding what actually happens during a high wind event. 

“Once we fully understand the dynamics of water intrusion and how it occurs, we can find a better way to manufacture and build,” says Blakely. “We hope to [develop] comparisons between traditional methods of testing and real-world weather events.” 

Steering Through
Faced with costs of nearly $40 a minute to run the simulator, the biggest obstacle for the project is money. Most of the funding comes from state and federal government contributions, though they have received some financial support from the industry too. In fact, last year AAMA donated $60,000 for the purchase of a precipitation-imaging probe (PIP), which is used to capture high-resolution measurements of rainfall intensity. The data collected by the PIP will be used to establish a catalog of wind-driven rain scenarios for different storm intensities impacting various terrains. Masters and his research team will use that information with its simulator to recreate actual hurricane effects.

In addition, support from the industry has come in other forms too.

“That includes product donations and people spending time with us and visiting the lab to assist us in the design and execution of the experiments,” says Masters.

Another project challenge is that a lot of people are focused on wind speeds, when pressure on a structure is what the team is actually studying.

“I have to do a lot of explaining about how the pressures differ from terrain to terrain because the earth’s landscape slows down the winds, but increases the relative gustiness of it,” Masters says. “Trying to work with people and have them understand what we’re actually designing for is certainly a challenging part of the work.”

And what about the critics? They don’t bother Masters too much.

“I [don’t think there’s] anyone with a healthier skepticism than the research team. [Skepticism] is an integral part of doing good research, and we’re constantly checking the work to make sure it’s done correctly,” says Masters. “We understand better than most the challenges and complications of trying to recreate a hurricane environment in a lab setting and that’s why it’s important that we remain transparent and let people see what we’re doing. We know what our targets are and we hope to get there. If we don’t we’ll let everyone know.

”What’s Next?
Once the work is done, Masters says the results will be shared with the industry and test labs.

“First, we’ll be working with our oversight task force to analyze the data and develop consensus code conclusions,” Masters says. “In an ideal situation we hope to conjoin all these different opinions and come up with conclusions that make sense for everybody, including the person who makes the window, the person who installs it and the person who inspects it.”

Masters says they also hope to adapt the technologies for other applications, including multi-family and commercial structures.

“I think we have developed a model for industry interaction where the university has taken a pivotal role in bringing different groups together and getting them to work in a meaningful way,” says Masters. “We’re going to continue to apply that to future projects and there’s a wide range of issues we’re looking at [concerning] water ingress in general.”

For Cole, he says he says the significance of the project is proving that the entire wall system must work together. 

“All the elements of a wall must be designed and installed correctly in order to mitigate water intrusion,” he says. “In the past, most residential windows were only looked at from the structural point of view, which they have historically done a remarkably good job. Now it appears we are asking a residential grade window to perform to higher levels of water intrusion resistance during severe wind events such as a hurricane. I am also very interested to see if Dr. Masters’ research verifies the results of the AAMA/WDMA/CSA 101-A440 (Standard Specification for Windows, Doors & Unit Skylights) testing.”

While final conclusions are still a ways off, team members are already thinking about what they will be doing once it’s complete. And what’s at the top of that list?

“Sleep,” says Masters. 

Ellen Rogers is a contributing editor for DWM magazine.

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