Paul Bugner, head of maintenance at Coleman Tool & Manufacturing Co.’s new plant in Union Grove, Wis., replaces one of the air curtains that were installed to conserve energy but also help to maintain indoor air quality.

Coleman Tool & Manufacturing Co. is a welding, machining, and metal fabricating company that manufactures replacement parts, tools, and accessories for waste management trucks — refuse trucks, street sweeper repair parts and roll-off parts. When it opened its new plant in Union Grove, Wis., it specified air curtains above the shipping doors in order to save energy.

But, indoor air quality became a problem when industrial air cleaners couldn’t remove all the welding smoke from the operation: it formed a haze near the ceiling, and presented a significant environmental concern. Rather than spend tens of thousands to install rooftop ventilation equipment, Coleman engineers innovatively fabricated special air filters and metal holders for the air curtains, to clean the plant’s indoor air. They had established an entirely new use for air curtains.

“We hit two birds — energy savings and IAQ — with one stone (air curtain technology),” according to Coleman Tool president Michael Coleman.

For decades industrial plants have used air curtains above open doorways to save energy by separating interior and exterior environments. Coleman specified air curtains for its new 60,000-square-foot plant, built by a Wisconsin design/build firm, Design 2 Construct (D2C). An in-house mechanical engineering team, which performed much of the building’s mechanical engineering requirements with D2C, didn’t hesitate to specify air curtains for two 16 x 16-ft and one 12 x 12-ft overhead doors, because of the acknowledged energy-saving capability of this technique.

Now, Coleman Tool relies on one CFA and two CFC model air curtains, manufactured by Berner International, to retain heat while the doors are open, resulting in a significant energy savings. Consequently, the building now maintains a 60íF plant wintertime temperature generated purely from the waste heat of its industrial welding process production.

This contrasts with Coleman Tool’s former building, which had no air curtains, used supplemental heaters, kept the shipping doors open more frequently, and used exhaust fans to expel welding smoke. Unfortunately wintertime heat was exhausted, too. However, the new building now incurs no supplemental winter heating costs, significantly reduces heat loss during open door periods, and re-circulates heated air through the air curtains, all which contribute to the company’s ongoing green and environmental-consciousness mission, according to Paul Bugner, head of maintenance.

The air curtains, which are activated manually or with a limit switch triggered by a door opening, help maintain the temperature because they eliminate outdoor air infiltration. Air curtain technology draws interior air from the facility and discharges it through field-adjustable (+/-20 degree) linear nozzles to produce a non-turbulent air stream that meets the floor approximately at the threshold of the door opening. Temperature differences and prevailing wind conditions cause the majority of air exchange and resulting energy loss across the opening. An air curtain can contain approximately 70 to 80 percent of that air and return it to the space. Because the air curtain discharges at velocities generally in the range from 3,000 to 6,500 ft/min., the strong airstream shield prevents outside air and even insect infiltration.

To continually protect the door opening from these exterior forces, Berner factory-engineers these air curtain for size, air volume flow rate, airstream velocity and discharge nozzle uniformity, which is critical to air curtain performance. These aerodynamic performances are certified by the Air Movement & Control Association (AMCA) International, a not-for-profit association that assures accuracy in the specification claims of air curtains, fans, blowers and other air movement devices.

Filtering Welding Smoke
While Coleman Tool was tallying impressive energy savings figures with air curtains, the lack of air infiltration and cross-ventilation during the winter had affected IAQ. To control smoke and other airborne contaminants generated by Coleman Tools’ 10 Miller Electric welding bays and four igm Robotic Systems welding stations, mechanical engineers specified 14 Industrial Maid industrial air filter walls that surround the 15,000-square-foot welding area.