Coleman Tool specified air curtains at its new 60,000-square-foot plant in early 2010 to eliminate outdoor air infiltration and save energy. However, smoke rising up and out of the welding area  created an indoor air quality problem. So the air curtains also served as air cleaners.

Maintenance manager Paul Bugner replaces air curtain filters in the welding area at Coleman Tool’s plant in Union Grove, WI. Photo courtesy Berner Intl.

Industrial plants have used air curtains above open doorways for decades because the curtains eliminate outdoor air infiltration and save energy. This is why Coleman Tool specified air curtains at its new 60,000-square-foot plant in early 2010. Based in Union Grove, WI, Coleman is a welding, machining and metal fabrication company that specializes in replacement parts for waste disposal vehicles.

Berner International supplied the air curtains, which include CFC units above two 16-by-16-foot doors, and a CFA unit above a 12-by-12-foot door. The curtains are activated manually or with a limit switch triggered by a door opening.

Upon activation, the CFC and CFA units draw interior air from the plant and discharge it through field-adjustable linear nozzles to produce a nonturbulent air stream that meets the floor at the threshold of the door opening. The air curtains discharge at velocities from 3,000 to 6,500 feet per minute, creating an airstream shield strong enough to prevent infiltration of outside air and insects.

During the winter, the air curtains prevent the escape of waste heat from industrial welding that occurs inside the plant. This heat keeps the plant at a comfortable 60 F, eliminating the need for Coleman to incur supplemental heating expenses.

The curtains also significantly reduce heat loss during open door periods and recirculate heated air, both of which contribute to the company’s ongoing green and environmental-consciousness mission, says Paul Bugner, head of maintenance for Coleman.

To control smoke and other airborne contaminants generated during welding, 14 industrial air filter walls were installed around the welding area, which encompasses 15,000 square feet and includes 10 welding bays (with equipment from Miller Electric Manufacturing Co.) and four welding stations (with equipment from igm Robotic Systems).

Although the air filters worked well, an estimated 20 percent of the smoke rose up and out of the welding area, creating a haze throughout the plant at the ceiling-and an indoor air quality problem.

One expensive solution would be to install expensive make-up air equipment on the roof to recirculate heated air. Instead, Bugner theorized that the air curtains might also serve as air cleaners.

Some air curtain manufacturers offer options for conventional filtration add-ons. But Bugner felt heavy industrial welding smoke would need a filter holder designed for quick and frequent replacements to keep labor expenses in check.

“We designed a filter holder we could manufacturer ourselves, required only 10 minutes or less to replace, didn’t affect the air curtain’s airflow and would use inexpensive off-the-shelf filters,” says Michael Coleman, president of Coleman Tool.

Bugner says the indoor air quality is now much better. “The haze is gone, the production floor’s air smells fresh and the plant’s chronic asthma sufferers notice significant breathing improvements,” he says. “We hit two birds-energy savings and IAQ-with one stone.”

For more information on air curtains, call 800-245-4455 or visit