Iowa State University

Inside Iowa State
Feb. 20, 1998

It takes more than air freshener in confinements

by Steve Jones

Iowa pork producers have some special needs, and Steve Hoff has the expertise to help.

Hoff is one of the few agricultural engineers in the nation working on ventilation and air quality problems in hog confinement buildings. He isn't simply trying to keep the porkers comfortable, however.

Confinement buildings can be filled with dust, gases and high humidity. Over time, these problems can cause breathing ailments for people working in the structures. They also can affect the health of the pigs.

"It's a potential problem in Iowa," Hoff said. "There are many potential indoor air quality problems connected to raising hogs."

Specialized heating and ventilation systems are needed. In the summer, for example, systems must remove moisture and heat from the air, but too much airflow will chill piglets. In winter, economical ways to heat and reduce humidity are needed.

An associate professor in the agricultural and biosystems engineering department, Hoff has the right credentials for his job. He's trained in heating and ventilation engineering, in electronics for ventilation control, and in agricultural structures.

As an undergraduate engineering student at the University of Minnesota, Twin Cities, Hoff developed interests in indoor air quality and airflow. He also had a strong attraction to agriculture. Agricultural engineering enabled him to combine his interests.

"It's a great field to work in," Hoff said. "There are many challenges to tackle."

Hoff's interest in agriculture didn't come from growing up on a farm. He's a city kid from a St. Paul, Minn., suburb. But he took a liking to agriculture from stays at his grandparents' farms in northwest Minnesota's Red River Valley.

"I spent a lot of time on those farms," Hoff explained. "I enjoyed being around farming and the people in agriculture."

Last summer, Hoff's research received a major boost when the Air Dispersion Laboratory opened. Hoff uses the lab to test ventilation systems in a simulated pork production environment. Located west of Ames, the lab is the only one of its kind in the United States and one of only two in the world (the other is in Denmark).

"We invited eight ventilation companies to set up systems in our laboratory," Hoff explained. "These evaluations may help to improve systems to save energy, and to create a healthier, more productive and more comfortable environment for animals and employees."

Hoff believes work in the lab, funded in part by the Iowa Energy Center, will establish standards to evaluate indoor air quality and control in livestock buildings. No standards currently exist for livestock ventilation systems.

Hoff also is involved in outdoor air quality. He is helping develop a computer program that could help pork producers determine where to build confinement structures so that odors will be least offensive to neighbors. Hoff is collaborating with fellow ISU agricultural engineer Dwaine Bundy, who initiated the project several years ago.

The program looks at topography, wind currents, trees, existing confinement buildings and other factors that affect the flow of odors. The first version of the product should be available by midyear.

Hoff's interest in the program goes beyond the professional level. Living on an acreage near Jewell, the program could ensure odors from new confinement buildings aren't too great of a nuisance for his family

"Living in the country has given me a really nice opportunity to know what people are experiencing," Hoff said. Although his acreage is rarely bothered by odors from nearby confinements, he realizes some rural residents aren't so lucky.

"There's no question that the industry must be careful where it places buildings in relation to people," Hoff said.

Hoff's research fits nicely with his teaching. He teaches undergraduate and graduate courses in ventilation design, heat transfer, and instrumentation and control.

"Steve's one of our best teachers," said Stewart Melvin, head of agricultural and biosystems engineering. "He's really popular with the students."

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