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Air Curtains: First Line of Defense for Employee Safety
Chalk up workplace safety as yet another use for the air curtain. For decades, air curtains, sometimes referred to as air doors, have been used in commercial and industrial applications to reduce energy costs and separate environments, plus a myriad of other functions not directly related to safety.
Now with the Occupational Safety & Health Administration (OSHA) recently pinpointing a growing trend of vehicle emissions sickening quick serve restaurant (QSR) drive-thru window operators, air curtains are seen as a low cost safety device to avert this growing concern over potential carbon monoxide (CO) poisoning problems.
Feeding the trend is the fact that drive-thru transactions are continually rising and now constitute a majority of the QSR business culture, according to the National Restaurant Association (NRA). Therefore, it’s a good possibility that the restaurant industry’s unusually high average of 145-percent employee turnover rate, according to NRA statistics, could be partially due to this emerging challenge. Symptoms related to CO poisoning are headache, flu-like effects, heart problems, and fatigue.
Not only are drive-thru window employees involuntarily breathing vehicle emissions, exposure to temperature extremes in wintertime northern climate QSR’s also present a health risk as well.
On the “Teen Worker Safety in Restaurants,” page at www.osha.gov, OSHA recommends a “fan system to prevent vehicle exhaust from entering the interior drive-thru window area,” or rotating workers to minimize time spent stationed in the drive-thru area. Two other recommendations—keeping the drive-thru window closed more or providing adequate space and ventilation for both exterior and interior drive-thru areas—may not be practical solutions conducive to maintaining transaction frequencies or profitability.
An Arby’s franchisee, which derives 65-percent of its business from drive-thru transactions, has taken the lead as a beta test site for a newly-developed air curtain specially designed for drive-thru windows. Arby’s store #5775 in Struthers, Ohio, successfully kept vehicle emissions as well as temperature extremes out of the employee area, according to Vicki Vitullo, general manager of the Arby’s location, which is one of nine Arby’s franchises owned by Niles Restaurant Business, Youngstown, Ohio. The 18-inch (26-inch-long models also available) , low profile unit discharges air from top to bottom of the drive-thru window to maintain the all-important “split” of indoor/outdoor environments a few inches outside the threshold. The air discharge is strong enough to stop infiltrating outdoor air vehicle emissions and insects, but doesn’t blow paper money out of hands
penetrating the air stream.
The flying insect factor is another health and sanitation issue that protects employees as well as patrons against diseases transmitted mainly by houseflies landing on food.
While larger air curtains for other uses such as industrial and commercial applications typically involve skilled installers or contractors, many drive-thru units are easily wall-mounted with simple tools and plugged into the nearest wall outlet.
As for the extreme temperature exposures, some drive-thru air curtain models include on-board electric heaters to help maintain a comfortable ambient temperature as well as stop infiltrating exterior air.
Reducing Industrial Door Accidents
Air curtains are also important strategies for keeping industrial and commercial workers safe when passing through interior and exterior doorways. Thousands of workers are injured annually by industrial and commercial doors. The U.S. Department of Labor’s Bureau of Labor Statistics (BLS), Washington, D.C., reported 17,030 door accidents leading to nonfatal occupational injuries and illnesses involving days away from work by source of injury or illness and selected events or exposures leading to injury or illness in 2007. An additional six door incidents resulted in fatalities that year.
Of the 17,030 door accidents, 8,820 were “struck by an object,” the report states which in most cases is likely an automated door in motion. In many industrial and commercial instances, interior high speed doors record hundreds and many times thousands of cycles daily as pedestrians, forklifts, and battery-powered hand-operated pallet transporters devices pass through. The doors are kept closed typically to separate environments, such as a refrigerated warehouse where trucks are unloaded of products that must immediately be stored in a cool environment such as a cooler.
“Struck by and object” could also be the result of a forklift hitting a door and its separated parts falling on workers.
Many incidents result from high-speed doors with hard leading edges descending upon workers and striking them in the head and/or shoulders. Many times workers are struck a second time as the door ascends because a safety device controlling the door senses an obstacle and immediately retracts the door.
Another 2,180 accidents were due to workers “struck against an object,” which typically involves a worker colliding with a closed or semi-closed door. A frequent incident, especially in manufacturing and warehousing, is forklifts colliding with a door that’s closing unexpectedly. This can hurtle the driver against the forklift protective caging. Or the forklift collides with pedestrians on the other side of the door who expect a closing door to protect them.
Another 870 injuries resulted from “caught in, compressed or crushed” which is typically entrapment.
Obviously leaving the doors open during work hours potentially eliminates hundreds or even thousands of door accidents since many involve door cycling. However, open doors waste energy or allow environmental element infiltration that potentially can affect productivity or quality control. An air curtain positioned above the doorway can keep the cool and warm environments segregated, while also allowing the door to remain open during work hours. It should be combined with a rigid or solid locking door to maintain off-hours security. Air curtains can accommodate almost every size door opening ranging from small pedestrian doors to large 30-foot-high door openings for railroad cars.
When it comes to human injury, there should be no cost shortcuts. However, using an air curtain as a retrofit may be very cost-effective especially when an existing high speed door has already cost the company more than $10,000. Air curtains offer a much safer as well as more energy efficient scenario to doorways than another industrial or commercial method of separating environments—the polyvinylchloride (PVC) strip door, which is a series of vertical hanging strips that separates environments. Strip doors allow workers to pass through them by pushing them out of the way. The strips are transparent, but visibility is obscured over time because of yellowing, scratching and clouding. Forklift drivers accustomed to clear sightlines through the strips, don’t realize the slow degradation of visibility over time and could potentially drive through the strips and hit another unseen forklift, pedestrian or obstacle.
PVC strips can also become brittle and cut workers passing through when the edges become cracked and jagged. Air curtains on the other hand allow free unobstructed movement through the doorway with 100 percent visibility.
Air curtains also offer the safety factor in drying floors and reducing slippage. There are literally thousands of facilities around the globe that have cool refrigerated food storage areas adjacent to warm, humid trucking docks or other conditioned staging areas that supply the coolers. Since warm, humid air migrates toward cooler areas and condenses onto the floor near the entrance, air curtains can lessen environmental mixing while also drying floors. Air curtains can also be ordered with on-board heating coils (electric or central plant supplied) that dry floors quicker and/or enhance employee comfort near the doorway. Dry floors eliminate potential accidents due to slippage.
Likewise, many slippage accidents occur from moisture on metal trucking dock levelers that could come from refrigerated truck interiors or melting ice accumulations on the roof of the facility or truck.
Aside from increased visibility and floor drying, air curtains also have an entirely different purpose that affects employee health. Like drive-thru window employees, extreme cold or hot elements can affect employees stationed near exterior doorways. Because they’re designed to separate dissimilar environments, air curtains can also protect industrial workers from extreme temperatures infiltrating their work stations.
Industrial air curtain applications are also invaluable against flying insect infiltration, especially in food manufacturing and processing plants. Etymologists, for example, have proven the ordinary housefly leaves harmful bacteria deposits on food it lands on. Because the feet of flies have pads with hairs that exude a sticky substance, they are germ traps that leave behind bacteria residue once the fly leaves. Therefore, keeping flies and other flying insects out of industrial food production is a health and safety concern for the entire population.
While air curtains have been commonly used for decades to separate environments in the workplace, perhaps now is the time safety professionals should consider them to help eliminate industrial/commercial doorway accidents as well as keep restaurant drive-thru employees safe from CO poisoning and wintertime temperature extremes.
