November 2008 Edition

FILTRATION

Clearing the Air

Maintaining a healthy shop environment means more than clean machines. Defeating indoor air pollution benefits both the shop and those in it.

There may not be fire where there’s smoke, but fumes in the air of a shop can be a sign of a degraded environment. Keeping the air clear not only can keep employee lungs healthy, but also can mean avoiding violating occupational safety regulations.

Five years ago, Toyo Seat Programs Planning Manager Ken Swanstrom was nervous when he walked down the hall with a purchase requisition to buy an air filtration system for a welding line at the Imlay City, MI, plant.

Toyo Seat had added various air filtration systems as the plant grew, but they were still seeing smoke in the plant and some of their fume collectors had caught fire. Management made the decision to renew its commitment to air filtration by making the investment needed to capture all fumes and smoke, reduce the risk of fires, and improve employee safety.

"I was going out on a limb and there were a lot of people watching me to see if I made the right decision," Swanstrom said of his decision to use RoboVent air filtration products from Great Lakes Air Systems, Clawson, MI.

Five years later, Toyo Seat management and Swanstrom are sure the decision to invest in improving air filtration was a good one.

Air quality has improved up to 500 percent inside the plant, and Tim Dufort, plant superintendent, credits cleaner air with a positive effect on employee motivation, absenteeism, and productivity. Dufort said customers have also noticed cleaner air in the plant.

"We have people visit here and say: ‘This is a welding shop?’ " Dufort said.

Proof is in the Breathing

Highlights of the air sampling results taken after installation of the RoboVent air filtration system showed

• airborne particulate concentration ranged from less than 0.001 mg/m³ to 0.00028 mg/m³. The airborne arsenic concentrations measured at the facility ranged from approximately 50 to 100 times lower than the eight-hour time-weighted average Permissible Exposure Limit – PEL – of 0.01 mg/m³ established by the Michigan Occupational Safety and Health Administration – MIOSHA.
• particulate matter/oil fume concentrations ranged from 0.36 mg/m³ to 2 mg/m³. The airborne particulate/oil fume concentrations measured at the facility ranged from approximately two to 10 times lower than the eight-hour time-weighted average PEL of 5 mg/m³ established by MIOSHA for respirable particulate matter and oil mist.
• welding fume concentrations ranged from 0.36 mg/m³ to 2 mg/m³. The airborne welding fume concentrations measured at the facility ranged from approximately two to 10 times lower than the eight-hour weighted average PEL of 5 mg/m³ established by MIOSHA for welding fumes.
• mercury vapor ranged from 0.00074 mg/m³ to 0.0008 mg/m³. The mercury vapor concentrations measured at the facility were approximately 60 times lower than the eight-hour weighted average PEL of 0.05 mg/m³ established by MIOSHA for mercury vapor.

Toyo Seat manufacturers seat parts including seat frames, seat backs, and recliner mechanisms for auto manufacturers. Toyo Seat uses a variety of welding processes including 70 welding robots.

Before the installation of air filters, smoke and particulate matter from the welding operations at Toyo Seat was a visible problem	After installation of air filtration systems from Great Lakes Air Systems, interior air quality improved significantly

Keeps the Floor Clear, Too

Conserving floor space was an issue for Toyo Seat as it looked at air filtration systems.

"We wanted floor space conserved and Great Lakes came up with the FloorSaver system," Swanstrom said of the RoboVent air filtration system that takes up no additional floor space in the plant.

The RoboVent floor saver collection unit is mounted above the welding cell. The collection unit consists of housing with a blower, motor, silencer, filter cartridges, and a compressed air pulsing system to clean the filters.

The collection unit uses a patented filtration process in which air flows in a downward path. This provides more efficient air cleaning. As the collection unit receives air from the hood, it shifts the airflow 90° downward through the filter elements where the air is cleaned. This causes separation and deposition of the larger, heavier smoke and welding dust particles, which reduces the load on the filter cartridges.

Because the air filtration systems were installed above the welding cells, they did not take up additional floor space in the shop

The air down-flow in the collection unit reduces air turbulence and eliminates re-entrainment, or reblowing dust within the collection unit that has already been cleaned from the filters, back into them. Re-entrainment is the primary cause of short filter life.

The units use vertical filters, which are more efficient and have a longer filter life than the horizontal filters used in most air filtration units. Vertical filters let collected dust and debris shed from the filter and fall with the airflow into the collection tray when the filters are pulsed by the filter cleaning system.

"We found that dirt and debris tends to fall off only the bottom two-thirds of a horizontal filter, rendering the top of the filter ineffective as it becomes clogged with debris," John Reid, president of Great Lakes Air Systems, said. "This results in up to a 40 percent loss in filter area and a substantial reduction in filter life."

The proprietary filter cleaning system keeps filters clean and extends filter life. Each time the unit shuts down, the automatic cleaning system sends a pulse of compressed air to blow debris off of the filters, keeping them clean. The debris in the collection tray is removed by maintenance personnel.

Toyo Seat’s investment in air filtration meet management expectations, have a positive effect on working conditions, and protect both the interior and exterior environment. Great Lakes Air Systems

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