Avoid A Dust-Up

Features - Feature

Responsive suppliers are providing contractors and recyclers with access to effective, affordable dust control.

July 15, 2010
Curt Harler

Next to maintaining household harmony, C&D recyclers know that keeping neighbors, workers and government officials happy makes life much easier. At facilities and job sites, that means keeping dust and particulate matter under control.

Buyers of dust control equipment generally cite avoidance of nuisance complaints from neighbors, employee health and regulatory measures as reasons for dust control. All three are valid reasons to buy dust control equipment.

While the technology has changed for the better, many of the regulations regarding particulate matter have become stiffer.

“As a manufacturer of dust-control equipment, I’d say the big challenge is the disconnect between production and pollution control,” says Mark Kestner, president and CEO of NESCO, Hackettstown, N.J. Based on his 33 years in the business, he says many companies will spend money on pollution control or worker safety only if they are forced to do so. “People should realize that this equipment can make you more efficient and effective. People work better in a healthy environment.”

The U.S. Department of Transportation (DOT) requires dust control on road work. Whether it is concrete crushing or other demolition activity, the Occupational Safety and Health Administration (OSHA) and the United States Environmental Protection Agency (EPA) have specifications for worker and environmental protection. New dust control technology is helping C&D operators meet those challenges.

While he agrees that state and EPA rules are getting tougher by the month, Marty Grace, sales manager for Company Wrench, Carroll, Ohio, says the real push is from large cities. “The bigger the city, the more compelling the regulations are,” he says. Places like New York, Chicago and many California cities are on his list. “Some have incredibly stringent regulations,” he comments.

Although Grace questions some of those cities’ ability to enforce those regulations today, he remarks, “They are in place,” and says they will become a focus down the road.

“Dust control is something you do because you have to do it,” Kestner says. “Ninety percent of the time, [companies] install a system to avoid nuisance dust and neighbor complaints. To a much lesser extent it is health and safety related.” He notes that many C&D firms equip crane or loader cabs with positive pressure systems that keep the dust away from the operators.

“Most sites could benefit from effective dust control measures,” Grace says. Benefits range from a safer and cleaner work site to less frequent maintenance cycles and increased productivity.

A good dust system does more than dampen dust. “Most companies are able to see the tangible benefits from happy neighbors to a more productive worksite–eliminating the employee with the fire hose,” Grace says.

While he agrees that most initial demands are driven from compliance-type regulations, he says most companies are happy they took the steps to reduce dust after their initial use of a dust suppression machine.

One type of technology being offered to the market comes in the form of rotary atomizing nozzles. Probe Industries and Buffalo Turbine are among the companies offering this dust control option.

“Twenty years ago we used hoses and spray nozzle systems,” says Brad Wesley of Buffalo Turbine, Springville, N.Y. A decade ago electric portable “snowmaking” style systems with nozzles and electric driven rotary atomizers became more common. More recently air-driven gyratory atomizing nozzles, turbine style fans and electric, gas, diesel, hydraulic or PTO driven products have come to market, says Wesley.

“With rotary atomizing nozzles you don’t need high-pressure pumps or big tanks of water,” explains Wesley. “You could hook the system up to a kitchen sink and run it.”

Probe Industries offers an electronic version of rotary atomizing. Buffalo Turbine’s version is a spin-screen technology that pushes water through a screen. Little wings on the nozzle spin at 5,000 to 6,000 rpm with the result being water that is pulverized and atomized into a fine mix.

Kestner says he sees increasing demand for systems that offer options to the traditional electronic controls and says more operators want hydraulic or diesel control.

“The biggest change in our industry is variable particle size,” says Rick Felde, marketing manager for Dust Control Technology, Peoria, Ill. “This allows you to match the size of the water particle with the size of the dust particle.” Dust particles and water particles attract best when they are roughly the same size.

While typical brick or concrete particles run in the 50 to 200 micron range, other materials dust up in different sizes. Asbestos, a problem on many jobs, makes a smaller particle than concrete.

Wesley says the volume of water depends on the type of dust, amount of dust, and amount of allowable saturation to the end product. He says that a rotary or gyratory atomizer can produce more fine water droplets per gallon of water than traditional spray type nozzles after a period of use.

“Matching the size and number of nozzles to the particle size allows you to avoid the slip-streaming effect,” Felde says.

NESCO’s Kestner likes to mount mist-spray equipment right on the front of the loader or shear. “This gives the operator better control,” he says, pointing to an Idaho demolition firm that had been using fire hoses for dust suppression. Kestner also notes the wisdom in matching water particle size to dust particle size. “Fire hoses are not particularly effective,” Kestner says. Plus, the water generated must be cleaned up before it can be discharged.

While dust-control systems are not cheap, there are several signs that the market – while expanding for manufacturers – will stay reasonably priced for recyclers. One big factor is the broad array of applications for mist-making products.

“Most of the units on the market today can also provide a means of nuisance odor control,” Grace says. Transfer stations, landfills and compost yards find that dust suppression machines fill a value need in their industries, he says.

Fire control has been another driving application for all sorts of water-dispersal equipment. In fact, until OSHA and EPA got involved in dust-suppression regulation, many C&D operators used fire hoses and even lawn sprinklers to hose down sites.

Throughout the West and Midwest, misters are catching on at huge cattle feedlots where they are used to keep animals cool and comfortable. Another area is PPV (positive pressure ventilation) fire control where systems are used to keep stairwells in tall buildings cool and smoke-free during fires, allowing people to get out safely. Even more than the C&D area, these areas are growing markets for mist equipment.

Company Wrench’s largest market segments have been large scale demolition projects and hazardous waste remediation sites. However, Grace notes that the material handling trades such as concrete and aggregates, cement, mines and quarries, landfill and waste transfer sites–along with recycling and scrap industries–are becoming much more active with their dust control activities.

Steel slag pits are another area where cooling equipment is getting more play. “Airborne fugitive dust is unhealthy from any type of application,” Wesley says.

Grace says their smaller units, the DF5000 and the DF7500, have applications indoors as well as outdoors. He also cites applications ranging from waste transfer sites to steel and slag applications.

NESCO does much of its work in the quarry area, although the company produces systems for both indoor and outdoor applications. Indoors, the application tends to be an overhead nozzle system in the rafters that helps settle particles in the air and disperse diesel fumes.

“When you specify dust-control equipment, look for a specialist,” says Felde. He says some companies offer equipment intended for other industries to C&D operators. “That might work on small jobs, but when you need to do a big job, look for an expert,” he remarks.

“Look at the construction of the equipment, too,” Felde says. He remarks that Dust Control Technology’s equipment comes with a three-year, 3,000-hour warranty. The company also offers a lease-to-own or a straight rental program.

“Many demolition contractors prefer to own their own equipment, but these programs let a contractor look at a machine and see how it works with a specific problem and how it works on the jobsite,” Felde says.

Dust Control Technology’s latest feature is an option that gives 180-degree oscillation on its larger machines. Up from 50 degrees on earlier models, it quadruples the coverage with their DB-60 from 21,000 square feet to 80,000 square feet–about the size of one-and-a-half football fields. “You now need one machine versus six or eight machines that give 10,000-foot coverage,” Felde says.

Wesley downplays the value of square-foot coverage statistics and suggests that potential buyers apply the pi x radius squared formula if they must have a square-foot number. “Rather, you should utilize a throw distance–both horizontal and vertical--and water volumes needed,” he says. His products can spray at rates from 8 ounces per minute up to 25 gallons per minute from each machine, he says.

“Technology will continue to drive how little water we can use and how far we can place it,” Grace says. He notes that many American universities are testing fan and nozzle configurations to maximize the metrics. He is even keeping an eye on research in Italy that is targeted at creating finer and finer water particles to match with dust particle size.

“We’ll see high velocity fans driving water from precision nozzles into a predictable micron size capable of capturing the dust particles,” Grace continues. In addition, he expects the newer generation of dust suppression machines will regulate the volume of water to accommodate a specific dust control task. “This leaves the sites without such equipment a ponding or run-off issue to deal with,” he notes.

Regarding throw distances, Kestner says it is more effective (and cleaner) to use a system that is not susceptible to the wind. “The big problem is keeping them targeted on the work area,” he says, noting that installing mist nozzles right on the equipment uses less water and produces no significant site run-off.

“Attention and focus on dust control are only going to increase,” Felde predicts. And he also advises, “Many things can go wrong if you are not paying attention to potential hazards.”