Mall Demolition Showcases Dust Suppression Technology
Published: 24/7
BossTek, the manufacturer of the popular DustBoss® family of dust control cannons, understands that when several different types of materials are demolished and separated into recycling or waste piles, they release different kinds of dust that can be a challenge. Recently, the cannons played a key role in aiding the Adamo Group of Detroit, Mich., demolish Eastland Shopping Center in nearby Harper Woods. Though the complex encompassed a wide variety of materials, not to mention 60 years’ worth of dust, the job was completed with no dust emissions, complaints, or costly violations.
Opened in 1957, the Eastland Shopping Center was considered one of J.L. Hudson Company’s most ambitious department store expansion projects, but occupancy began to wane and the property was sold.
The entire demolition project from start to finish took eight months. Using several pieces of equipment in the fleet, including a mid-sized high-reach crane, front loader, magnetizing machine, etc., the Adamo Group dismantled the structure. An integral part of this was the DustBoss® DB-60 misting cannon. Directed toward the activity area, the fine engineered mist raised the humidity of the area, preventing dust from becoming airborne and traveling into the surrounding community, as well as protecting workers on site from hazardous dust.
To capture small airborne particles, the droplets need to match the general size of the particles so that they can collide. The combined mass causes them to drop to the ground. Droplets greater than 200µm, like those created by hoses or sprinklers, are large enough to cause a slipstream current to move around them, which actually repels smaller particles and leaving them to remain airborne.
Automated mist cannons like the DustBoss DB-60 produce droplets approximately 50-200µm from a misting ring in the front which are propelled long distances by a powerful fan that pushes air through the rugged barrel. The droplets offer both airborne and surface suppression using only a fraction of the water required by hoses or sprinklers. They have proven to be more effective, cheaper to run over the long term and require no workers to operate.
Mist cannon technology
The two DustBoss DB-60 cannons are BossTek’s mid-sized fan-driven designs. Each cannon is 81 in (2 m) wide, 117 in. (3 m) long, and 86 in. (2.2 m) tall, and weighs 1,800 lb (816.5 kg). Mounted on roadworthy wheeled carriages, the cannons can easily be moved to where they are needed by a pickup or vehicle equipped with a hitch.
The units have an adjustable elevation angle from 0-50?, with a throw distance of 200 feet (60 m) of fine mist propelled in a wide cone by a 25-hp (18.6kW) fan running at 30,000 ft3/min (849.50 m3/min). When running with the optional 359? oscillation, each machine can cover more than 125,000-ft2 (11,600 m2)—2.5 times the area of a U.S. football field.
The cannons are equipped with a 1-1/2 in (38.1 mm) cam-and-groove quick disconnect female hose coupling. Connected to municipal hydrants with variable pressure, the DB-60s require only 10 psi (.69 bar) of constant pressure. Water passes through an in-line 30 mesh 595 micron filtration system that captures any impurities in the water that might foul the lines. The water then enters a booster pump where the pressure is increased to the adequate level needed for the 30 specially designed nucleating nozzles attached to a brass mandrel to fracture the water into millions of minuscule droplets. The use of a booster pump allows the DustBoss to use a fraction of the water of hoses, only up to 26.7 gal/min (101 liters/min).
The general rule for demolition dust is to avoid any situation that yields complaints from the public, as complaints regarding air quality submitted to the city or local EPA can trigger an inspection. Like most of Adamo Group’s projects, no complaints were lodged for the Eastland Shopping Mall demolition. The addition of more robust dust suppression means that the company can have two units on large projects or split them between smaller projects as needed. This ensures that projects can keep operating in adverse conditions where dust may have been a problem in the past.