Research aims to reduce damage in home fires

CEE Professor Steve Cramer and structural engineering graduate student Onesty Friday examine pieces of drywall tested in the tensile and compression loading machine behind them. The data obtained will help Cramer understand the basic properties of gypsum drywall. (39K JPG)

A lifetime of fire safety research really hit home for Steve Cramer early one morning in the spring of 1992. At about 4 a.m., the UW-Madison civil and environmental engineering professor woke to the smell of smoke: a small appliance in his children's bedroom was on fire. While flames burned inches from his baby's crib, Cramer rushed his pajama-clad family to safety. Taking steps three at a time, he bounded back to the bedroom and extinguished the fire before it engulfed the room.

"You get a different technical perspective when it happens to you," he said. "It was really a jolt."

The experience makes Cramer even more passionate when it comes to fire safety research. With the help of a National Science Foundation grant, Cramer recently embarked on a two-year project aimed at reducing the estimated 4,000 deaths, 17,000 injuries, and $6 billion in property damage caused each year by fires in residential construction. The project will develop guidelines for improving fire resistant construction using gypsum drywall, a fire resistant material routinely used in light frame construction like homes and smaller commercial buildings. The pile of local newspapers on Cramer's desk illustrates the need for research: each paper details a fire during the first month of this year. Cramer shuffles through the papers, reading one headline after another:

• Jan. 1, Fast moving blaze forces 40 to flee Fitchburg building.

• Jan. 8, Two historic LaValle buildings burn.

• Jan. 9, Flame consumes historic tavern in Eau Claire.

• Jan. 11, Water heater expected cause in home fire.

"Maybe you read the paper every day and these things slip by," said Cramer. "While we didn't lose any lives in these fires, there was a vast amount of property and home damage.

"We're not prepared to tolerate massive losses in one event like an earthquake, but we've come to accept similarly extraordinary losses from small fires that occur day after day. "Fires don't have quite the attention in building construction research that earthquakes do, but these headlines suggest that maybe they should. I would propose that they should."

Cramer's efforts to reduce fire damage are based on the chemical properties of gypsum drywall. When gypsum heats up, it chemically releases moisture, and the energy created by the fire's heat drives that moisture to the surface. This process delays the effects of the fire, protecting the wood or steel frames in the walls, roof and floor for a longer length of time.

Standard fire tests used to approve construction techniques show that building supporting elements fail quickly once gypsum drywall falls from the area that it is supposed to be protecting.

"When the gypsum comes down, it's all over," said Cramer. "Finding a way to keep the gypsum attached to walls and ceilings longer would provide an important delay in the destruction caused by a fire. We're not talking about something exotic like a new building design or adding such a vast expense to construction that people aren't willing to pay. We're talking about something that may cost little or nothing, but might give a few precious minutes in a fire."

Cramer began his research by searching for information on the physical properties of gypsum, but no one — not even the gypsum drywall manufacturers — could supply the basic engineering data he needed; it simply didn't exist. Without it, it would be impossible to design a longer-lasting attachment method.

Therefore, Cramer's first efforts include gathering that data himself. With the help of graduate students and a couple state-of-the-art testing machines, he is running a variety of tests to find the data they need to move forward.

From these conclusions, Cramer will identify a way to hold the gypsum board in place longer, increasing the life of the wood frames. "We have a variety of tests to run," said Cramer. "Ultimately, we'll build intermediate-scale ceiling assemblies and test them at the USDA Forest Products Lab fire testing facilities."

The team will use a four-foot by five-foot furnace to conduct scaled-down floor/ceiling assembly tests that show which connecting methods work best. During these tests, the team will closely monitor temperatures on both sides of the gypsum and near connection points. Indicators will show when and where the gypsum detaches from the frames.

Cramer anticipates several major results in this project. First, the research will allow him to develop a database of basic gypsum board properties for fire-endurance design. Then he'll identify causes of failure for the fire resistant gypsum and create a model to predict the life of the drywall during a fire.

Not surprisingly, Cramer's own experiences have stoked his interest in fire. "My own experience with a home fire gives me a more personal perspective on the technical problem," said Cramer. "Fires tend to be very emotional, dramatic events that have a big impact on people's lives. It's not often that an engineer has first hand experience with the bigger picture."