Dust Control Inside and Out: Demolition Company Solves Emissions Problem
Published: 21/12, 2021
By Mike Lewis, Vice President, BossTek
Demolition experts know that every site has its unique challenges with dust. This is particularly true when stripping potentially hazardous materials from indoor projects and separating materials for recycling. Both indoor and outdoor work can create vast amounts of dust that could violate emissions regulations established by the US Occupational Safety and Health Administration and the Environmental Protection Agency.
With air quality standards getting tighter and more sites located adjacent to residential areas or active commercial zones, contractors are showing a preference for demolition companies that forgo the common handheld hose dust suppression method for more modern and effective measures. That’s the case for East Coast Demolition, a full-service hazardous material abatement and demolition contractor serving northeastern North Carolina and Virginia.
The firm was contracted to demolish, recycle, clear and prep the old site of The Village Shops at Kingsmill in Williamsburg, Va. Due to its proximity to residential communities and local businesses, the general contractor selected East Coast Demolition for its experience in the proper handling of hazardous materials and dust suppression methods.
“We take environmental hazards very seriously because we want to be good stewards of the communities we serve,” says Ricky Webb, COO of East Coast Demolition.
The project involves demolishing seven brick and cinderblock structures totaling approximately 81,000 ft2 (7,500 m2) and more than 4 acres (1.6 hectares) of asphalt flattop in 10-12 weeks. One of the challenges was removal of the roofing and floor tile, which both contain asbestos. The task of soft-stripping these elements is often done by hand to avoid producing excessive dust.
To mitigate potential worker exposure to asbestos fibers while meeting the accelerated schedule, East Coast Demolition is using heavy equipment and a specialized dust control machine called the DustBoss Atom.TM This approach improves safety and drastically reduces the amount of time needed for internal stripping.
“We’re able to separate and recycle more than 85% of the material, including concrete structural constituents, piping, etc.,” says Webb. “This environmentally sustainable approach is a foundation of our business and also an element that sets us apart from other contractors in the region.”
Dust and demolition are inseparable. Some pros can tell what kind of materials are being demolished merely by the smell of the dust. However, smelling the dust is what demolition companies are trying to avoid. Webb points out that the company’s objective is to control both visible and unseen particulates.
“When people see plumes of dust, they get concerned,” Webb says. “We could have a worker with a hose spraying down the material but often times this isn’t enough to cover a widespread area. It’s the dust you can’t see that’s really harmful, so our goal is to control even the smallest dust particles.”
Atomized misting machines are more effective than hoses, because the millions of tiny droplets they create capture particulates at the point of emission, pulling the dust to the ground before it can travel long distances. Hoses provide only surface suppression, leaving airborne particulates of any size free to roam off the site.
The greatest drawback to basic control methods such as hoses and sprinklers is droplet size. Water droplets produced from hoses and sprinklers are simply far too large to produce any meaningful benefit in controlling airborne dust particles. Atomized mist is a much more effective option, as it relies on the principle of creating tiny droplets of a specific size range and delivering them over a wide coverage area, inducing collisions with dust particles so they quickly settle to the ground.
“We set up dust monitors at either end of the site to ensure that even the smallest fugitive dust isn’t escaping the site line,” says Webb. “The DustBoss units do a great job of pulling particles out of the air, so our monitors rarely register any change from normal atmospheric dust levels and show no toxic emissions.”
Indoor and Outdoor Suppression
A few years ago, East Coast Demolition started using atomized dust suppression with two DustBoss® DB-60 cannons, which are mid-sized fan-driven designs. The DB-60 units have an adjustable throw angle from 0-50° elevation, and when they’re equipped with optional 359° oscillation, each one can cover more than 125,000 ft2 (11,600 m2).
Having successfully utilized them on large private and government contracts, site managers felt that the DB-60 units were too powerful for this project. Operators needed a small and maneuverable dust control solution with a self-contained power source. Working with BossTek®, the manufacturer of DustBoss products, managers decided to try two of the company’s innovative DustBoss Atom machines, which are powered by a diesel engine and are easily moved by a single worker.
Since the Kingsmill project featured tight areas that require more precision, the DustBoss Atom produces a highly pressurized water stream that fractures into mist. Using its oscillating head, the compact unit delivers both airborne and surface suppression at a fraction of the water volume of manual spraying, helping to minimize oversaturation and pooling.
A standard hand-held ¾-in (19mm) hose attached to a hydrant generally delivers up to 22 gpm (83 lpm) of water. Instead of relying on water pressure, the Atom uses a 1-in (25mm) hose attachment from a water source running to a pump powered by a 9.1-hp (6.8kW) diesel engine. The increase in pressure from the pump rather than relying on pressure from the hydrant means the design uses only about 7gpm (26 lpm). This greatly reduces wastewater runoff and the amount of standing water in the area, allowing the machine to be distant from the water source and still deliver superior dust control.
With a throw of approximately 100 ft (30m), the unit’s 0-65º vertical adjustment and 100º maximum oscillation range increase the coverage area to 6,100 ft2 (567 m2). Using the unit’s hand-held remote control, operators are able to set the oscillation range from the cab of their rig or at a safe distance from the demolition zone.
“A single worker was able to wheel the Atom around by hand, place it, determine the optimum settings, and go do something else,” Webb says. “This is a lot safer and more cost-effective than standing there with a hose in a puddle of water near large equipment and falling material.”
Safety, Cost and Time
There were some clear advantages to having precision dust control. One is that workers can stay protected in enclosed cabs and change the Atom’s settings with a remote control. Another is the dust’s effect on equipment. In the past, workers performing demolition inside structures had to clean the excessive buildup of dust out of equipment air intakes and radiators to prevent engine breakdowns. Since dust is addressed at the point of emission, this activity is reduced considerably, saving maintenance time and protecting valuable equipment.
“Having workers protected in their equipment allowed the soft stripping process to go much faster, so we could complete the project days ahead of schedule,” Webb added.