Applying the rule of three to dust suppression

The DustBoss is placed by a single worker in minutes and the settings are easily adjusted by remote control.

PHOTO CREDIT: ©BOSSTEK

Most would agree that prevention is better than a cure. But the fact is that we humans usually get into a situation where we’re forced to find a ‘cure’ to fix a problem, before we figure out how to prevent the problem in the first place.

Fortunately, when it comes to silica, asbestos and fugitive dust on demolition, construction, industrial, mining and quarrying sites, we are at a stage where we have a number of measures that can be employed to prevent dust from entering the atmosphere.

Unfortunately, while the use of direct dust prevention methods such as the use of mist cannons is now common practice on most demolition sites, the number of contractors taking adequate action to prevent fugitive dust is less clear, particularly when it comes to smaller projects.

Mist sprayed from dust cannons settles evenly across surfaces, allowing it to be better absorbed with less saturation or pooling.

FUGITIVE DUST

Fugitive dust - the small airborne particles of dry ground material (mainly mineral dust from the soil) released into the atmosphere when disturbed by human activity or the wind - can have just as damaging an impact on people as silicas or asbestos.

Prolonged exposure to fugitive dust – a term that by definition does not typically include artificial compounds such as hydrocarbons, but that in actuality includes any and all particulates present in the soil at a given location – can cause everything from skin irritation and respiratory problems, to neurological damage and cancer.

(And of course, the above does not take into account the conditions it can also cause in wildlife or the physical impact it has on vegetation and bodies of water.)

THE RULE OF THREE

It is the global consensus that humans can go three weeks without food, three days without water, but only three minutes without air, thus ensuring good air quality is the first priority.

Michael Kelley, President at BossTek, tells D&Ri: “When regulators from the Occupational Safety and Health Administration (OSHA) attach a Personal Dust Monitor to a worker, they are measuring exposure, regardless of whether a mask is worn or not.

“Generally, inspectors are looking for Respirable Crystalline Silica (RCS) particulate matter (PM) smaller than 10 microns (μm) in size at less than 50 micrograms (μg) in weight over an 8-hour time-weighted average (TWA), i.e., a single shift.

“Once measured, inspectors usually order violators to address air quality, regardless of personal protective equipment.

“This is why preventing dust emissions at the source is more desirable than passive protection such as masks,” says Michael, adding that: “More and more, regulators are identifying atomized mist as their preferred method for airborne dust control.”

DUST CANNONS

Indeed, BossTek is one of number of companies that provides specialist dust suppressing equipment.

Its family of DustBoss DB-30, DB-60, DB-100, and DB-Surge models are designed to operate in “punishing industrial environments” and, with most remaining i operational more than a decade after their production, are “known for their durability and reliability”.

Pulled on a mobile carriage by pickup truck or moved by forklift, the DustBoss models can be simply placed in position and turned on, without needing a site operator remain nearby to operate the machines.

BossTek says: “Demolition contractors have benefited greatly from being able to move and place the cannon to provide dust control within minutes, with little disruption or labour.

The AquaCutter 750V from Aquajet.

PHOTO CREDIT: ©AQUAJET

Is hydrodemolition the missing link in dust prevention?

Equipment manufacturer Aquajet, which was acquired by demolition robot specialist Brokk in 2016, says: “The innovative method is one of demolition contractors’ most valuable tools for the efficient, cost-effective and precise removal of concrete from a variety of structures.

“It could be the missing piece for those looking to drive productivity and limit workers’ exposure to harmful dust and other health risks.”

An impact-free process, hydrodemolition utilises high-pressure waterjets as powerful as 40,000 psi (2,758 bar) to remove concrete and other materials.

Aquajet’s Managing Director, Roger Simonsson, says that compared to traditional demolition methods such as jackhammering, hydrodemolition offers many benefits.

“Because the method uses water, the removal does not produce clouds of dust that are typical with jackhammers or breaking tools,” says Roger.

“Further enhancing safety, a Hydrodemolition robot operator uses a remote control, allowing them to monitor the work at a safe distance.

“This enables operators to avoid potentially dangerous situations like working on ledges, flying debris and harmful dust exposure.”

According to Aquajet, the fact that the method also eliminates the physical strain suffered by workers when using high vibration handheld tools, means that demand for hydrodemolition is continuing to grow at a steady pace.

Inmalo’s Rotofog RFW80 model offers a throw of up to 80 m.

PHOTO CREDIT: ©INMALO

“If operators find they need to adjust the settings or oscillation, the units are accompanied by a heavy-duty remote that can be activated from a safe distance on the ground or from the cab of loading equipment.”

AUTONOMOUS DUST CONTROL

Similarly, Inmalo recently introduced its Rotofog RFW range of compact electric, mobile and fixed dust suppression systems in the United Kingdom.

Incorporating an oscillating mast and twin pumps, the autonomous Rotofog RFW dust suppression machines comprise two sections.

While the lower body houses the motors, pumps and the control board, the upper section “contains a powerful motorized rotational arm with a twin jet spraying head”.

Inmalo currently offers two Rotofog models, the RFW60 and the RFW80, which have spray throw ranges of 35 to 55 m and 55 to 80 m respectively.

They are suitable for longer-term demolition projects, waste handling, transfer hubs/stations, port authorities and quarries, and are available with an optional wheel base.

The Rotofog RFW60.

PHOTO CREDIT: ©INMALO

Inmalo says: “The RFW range provides a solution for dust suppression where power and reduced noise blend together in a unique product.”

PHOTO CREDIT: ©SPRAYSTREAM

Wall-mounted dust suppression

Spraystream recently installed its Wallmount S2.2 model for Belgium-based waste management and recycling company Containerverhuur Vantomme Containers.

A dust suppression machine that generates a consistent stream of microdroplets to capture airborne dust particles and prevent the escape of fugitive dust, this type of misting cannon offers a throw of up to 15 m and is mainly used for dust- and odour suppression in enclosed spaces.

Spraystream, which offers both large and small wall-mounted units, says the electrically powered S2.2 model can also be rotated to adjust the direction of the throw depending on where dust is present.

The company’s product portfolio also includes a larger model, with a throw of up to 50 m, that can be used outside. Both units are controlled from a central control cabinet.

It adds: “RFW units enable top levels of performances for dust suppression with the lowest noise levels of less than 58 dB at 20m. These are remarkable values when compared to competitive equipment on the market.”

INCREASING DUST CONTROL REGULATION

Of course, with concern for the environment now reaching a fever-pitch, equipment such as dust cannons won’t be the only dust control and suppression measures that contractors will be obligated to use.

Indeed, in May of this year, the government of Queensland in Australia, introduced a Code of Practice for the construction and manufacturing sectors, that aims to minimise the exposure of workers to silica dust, by taking measures to prevent its creation as much as possible in the first instance.

Similarly, in August, the city authority in Abu Dhabi, United Arab Emirates, sent inspectors to visit demolition sites across the city to impress upon them the importance of implementing suitable safety, health and environmental practices, with many contractors urged to monitor dust levels and to apply the appropriate prevention and reduction methods.

The next few years are certain to see more regional and national governments the world over bring in more stringent regulation, which will require contractors to utilise additional methods to ensure a good level of air quality.

Such measures are likely to include the use of synthetic fluids for surface treatment and water additives, such as those produced by Australian engineering specialist Global Road Technology (GRT), and will likely also see a rise in other methods of demolition, such as hydrodemolition. ■