When working on a demolition job in warmer temperatures, a stream of water is usually the basic building block of dust control. But in freezing temperatures, that method can get dicey—and icy. Spraying with water in the colder months can create slick conditions that are hazardous for workers to walk and work on. That doesn’t mean water has to be taken out of the equation, though. It simply needs a little modifying on the molecular level.
Enter water’s chiller cousin, snow, which can be equally as effective at mitigating dust in colder temperatures while assuring safer working conditions. Natick, Massachusetts-based HKD Bluemanufactures, rents and sells snow guns that double as water atomizers to provide efficient and environmentally sound dust control (among other unconventional functions, like smoke emission suppression and ice bridge construction). Gordon Santry oversees the U.S. division of HKD Blue, while his parents, Charles and Anni, oversee the product line’s parent company, HKD Snowmakers.
While some may see snow as a nuisance, Santry and his family have always seen it as a solution. Before founding HKD Snowmakers, Santry’s grandfather, Herman Dupré, set out to find a more efficient way to churn out snow thick enough to coat the slopes at the ski resort he operated in Pennsylvania. After 20 years of experimenting and honing, Dupré developed the technology for a snow gun that became the base of the business he founded with his daughter and son-in-law, Snow Economics, now known as HKD Snowmakers, also based in Natick.
About four years ago, Santry said engineers at the company discovered that the flurries, along with atomized water, could address a problem not normally handled by snow machines: controlling dust safely during winter demo jobs. Since then, HKD Blue has manufactured atomized water-producing machines both with and without snowmaking capabilities.
“With HKD Blue entering new industries and developing new technologies, I’m thrilled by the opportunity to expand our business and product line,” Santry says.
Let it snow
Santry says the snow produced from the snow machines, much like the real stuff, is a natural air cleanser. The crisp, pure feeling in the air after a fresh flurry isn’t just in your imagination. Snow really does make the air cleaner by capturing pollutant particles in the air as it wafts to the ground.
“As you’re forming a snowflake, the dust particle becomes the nucleus of the snowflake,” Santry says. “As the particulate is forming, dust latches onto the forming crystal and falls down to the ground. You’re ultimately left with a pile of dusty snow.”
That’s the concept snow guns can put to use, blasting a flurry into cascading buildings as they kick up dust. The snow creates a sort of suspended wall that prevents the dust particles from drifting beyond the work site, dragging them to the ground instead. The concept is similar to using a water stream, but snow provides a safer solution in the colder months. When a water stream is used for dust suppression in the winter, it can freeze on the ground and create slippery, hazardous conditions for workers, whereas snow simply creates more fluff for them to plow through.
Along with cleaning the air and creating a safer work site, Santry says snow can also be used as an alternative to plastic tarps to cover remaining brick, concrete, steel and dust on the ground in the winter months as site operators work to clean it up. While snow provides a more natural alternative to plastic tarps, it is also more cost-effective, as tarps can be pricey and sometimes need to be replaced multiple times during a project.
Two in one
Snow, of course, can only be produced in freezing temperatures, so it’s a viable dust control solution solely for contractors working during the winter or in colder areas. However, some snow gun manufacturers, like HKD Blue, offer dual capabilities in their product line so the equipment can be used year round. HKD Blue’s V-575 series of machines, for example, produce both snow and atomized mist—water that has been converted into fine droplets. The machine can generate atomized mist by using 25-horsepower pumps to pressurize water between 250 and 500 psi. Then, the water is pushed through the company’s GEYSER nozzle, which Santry says produces appropriately sized droplets to capture dust.
To make snow, the V-575 has three nucleator nozzles that introduce those tiny water droplets to expanding and cooling compressed air in a 7.5-horsepower air compressor, which begins the formation of ice crystals. The crystals are then projected into the bulk water flow of the central nozzle, facilitating snowflake production. Santry says that when dust particles meet forming snow crystals in the air, it facilitates further crystallization. Santry said nearly every part of the machine can be controlled remotely, preventing operator exposure to potentially harmful dust and debris.
“Every function of it, whether it’s dust emissions or emergency stopping, is completely remote-controlled,” Santry says.
Winter is coming
The combination of dust suppression offerings provided by HKD Blue’s equipment is something Thomas Frongillo, the owner and operator of F&D Truck Co., Inc. in Millbury, Massachusetts, recently took advantage of as he embarked on a large demolition project that began in the summer and stretched into winter.
Frongillo contacted HKD Blue in the fall of 2017 in search of dust suppression equipment that could fit in the bed of his pickup truck during demolition of the Notre Dame des Canadiens Church in Worcester, Massachusetts. HKD Blue worked with Frongillo for about two weeks to design a custom solution, which was then manufactured at HKD’s factory and sent to F&D Truck just in time to be in compliance with the Occupational Safety and Health Administration (OSHA) silica law implemented in the fall of 2017.
“Because we do our own manufacturing, we can do any sort of customization,” Santry says.
When Frongillo started the job in July, he used atomized mist from his custom V-575 SS, along with two asbestos sensors from subcontractors, to control and monitor concrete, asbestos, brick and silica dust as two Cat ultra-high reach excavators picked away at the 17,000-square-foot church. Rather than aim the spray at the top of the building, which would obstruct the operator’s view, Frongillo’s team aimed it at the ground to prevent the bulk dust emissions that come from falling debris.
While concrete and silica dusts tend to clog up sensors, Santry says the atomized mist prevented blockage and maximized uptime for the project, which wrapped up in November. And although demolition of the 89-year-old church stirred up some controversy among the community over its preservation, Santry says the project “didn’t get a single dust complaint, which was great.”
Now, winter is here, and so is the time to use snow during demolition jobs. Frongillo recently used his V-575 SS to coat leftover materials from the church demolition with snow as his crew works to clean up the site. Santry says Frongillo will be busy with wrecking and demolition jobs all winter—so much so that Frongillo recently ordered another V-575 SS to continue utilizing the power of snow on future job sites.
The author is the assistant editor for Construction & Demolition Recycling magazine and can be contacted at firstname.lastname@example.org.