Prior to the year 2000, the National Capital Region only experienced three tornadoes in its recorded history. Since then, there’s been 15.
Preparing a property for a tornado includes keeping large rooftop objects – think solar panels and air conditioners, for example – tied down or firmly attached to buildings to prevent them from being ripped off and causing injuries to bystanders or major damage to other buildings.
Research on the extent to which rooftop objects can withstand tornadoes is currently lacking. Elena Dragomirescu, an associate professor at the University of Ottawa Faculty of Engineering, is looking for answers.
“We don’t have enough analysis about Ottawa storms,” she says. “We need that so we’re prepared.”
Using a giant three-meter windbox, her research team is testing different solar panels and rooftop air conditioners to see which ones can withstand extreme winds of up to 290 km/h.
“We need to know how much force the rooftop elements can take before they start breaking apart,” says Dragomirescu.
The results will be recommended for the next update of Ottawa’s building codes – expected in 2020 – so that homeowners and real estate developers know which solar panels and air conditioners to use for rooftops.
Keeping roofs attached
But it’s not just the objects atop roofs that can be a hazard. A roof itself can become airborne in intense storms and cause enormous damage.
There is a solution: Dragomirescu says tornado steel brackets and straps in structural beams that are added during construction can keep the roof and the building firmly attached. The problem is that building code does not require tornado brackets and straps for Ottawa region because the city is still considered a low risk area for tornadoes. Dragomirescu says that has to change.
“Our buildings are like stacked chopsticks so they need something to hold them together,” she says. “Once a building is built, you can’t access all the parts of the building to add steel straps later. We need to change the codes quickly.”
Even though the tornado brackets and straps aren’t required, real estate developers can ask contractors to add it in their buildings from the construction phase. A set of straps for one home is estimated at $400 to $600.
Besides advocating for changes in the building codes, Dragomirescu also wants to raise public awareness about safety. In collaboration with her colleagues from mechanical engineering and computer science, Dragomirescu is developing a mobile app that will give tips on what to do before, during and after a tornado. The most important tips are to hide in a basement during a tornado and stay away from windows.
“No one died in last year’s tornadoes because everyone did the right thing,” she says. “That’s amazing!”
uOttawa professor creating fertilizer from renewable resource
When water drains from farmland, phosphorus enters into rivers and other waterways. High phosphorus levels can lead to toxic blue-green algae blooms. When these toxins enter drinking water, they can cause illness as well as liver and kidney damage.
Phosphorus from agricultural drainage and urban stormwater is difficult to treat as there are a multitude of sources throughout the watershed. Chris Kinsley, assistant professor at the University of Ottawa Faculty of Engineering, has developed passive filters to remove phosphorus but wants to make this process more environmentally friendly by creating renewable filters and reusing the phosphorus.
The renewable filters – which are still under development – would be soaked in light acid to release the phosphorus. Once the phosphorus is dried, it would be used to make fertilizer.
Kinsley believes his research is critical because phosphorus will soon become a scarce resource. Most fertilizers are made from mined phosphorus but in 20 to 30 years, many known sources could be depleted.
“This is the best time to do this research,” says Kinsley. “We don’t have a lot of time to find alternatives.”
