Calgary’s innovative wind warning system improves safety

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by Kathleen Renne

August marks a somber anniversary in Calgary. It's the month, six years ago, when three-year-old Michelle Kresk was killed by a piece of metal that was blown off a downtown construction site. That's what started the proverbial wheels in motion for the City of Calgary's one-of-a-kind Advanced Weather Forecasting System (AWFS) – Envision, created by RWDI Consulting.
Calgary’s innovative wind warning system improves safety

In the wake of the tragedy, the City of Calgary, the construction industry and Alberta Occupational Health and Safety struck an on-site safety committee to examine construction-site safety.

"We thought we'd identify the highest risk areas and we decided to put together best practices to deal with the top four risks," explained Cliff de Jong, a senior special projects officer with the City of Calgary.

One of the risks identified was loose materials on construction sites, which can prove particularly dangerous in a locale like downtown Calgary, where sudden wind gusts are common.

As a result, the committee issued a Request for Proposal (RFP) for a system that would provide "advance notification of seemingly freak windstorms."

RWDI Consulting – which started in Guelph but has an office in Calgary – came forward with its Envision system that provides wind forecasting that is both site specific and height specific.

"It's state of the art," said de Jong, adding he doesn't know of any other forecasting system that provides information with this specificity.

"Calgary is very much a leader in this," said Frederick Vine, EllisDon's director of business development and the current co-chair of the on-site safety committee.

The RWDI system offers a 48-hour forecast that gives an hour-by-hour breakdown of anticipated wind speeds at different heights for a particular construction project.

"You can get a three-second burst of wind that can take a piece of drywall and, if it's not properly secured, can send it sailing," explained de Jong.

RWDI has produced a chart that identifies what items might be at risk of takeoff for each wind threshold.

For example, the chart specifies that at winds between 75 - 89 km/h, items such as a half-inch nut, scaffolding, a five-eighth-inch drywall sheet, and plastic pipe/conduit, four-inch diameter are all at risk.

At 120-plus km/h winds, two-inch nuts and three-inch long bolts are in danger of becoming airborne.

The forecast comes out via email several times each day with information specific to the building site that the contractor is responsible for.

"You may receive information for two or three different heights on your particular project," explained de Jong, adding the leading edge of the project is particularly critical.

"It helps contractors understand what's at risk with the wind predictions and it helps them prepare for the day," he said, adding that might mean securing certain items, altering the start time of certain tasks or re-scheduling them altogether.

De Jong said the wind forecasts can be markedly different depending if a project is in the centre of Calgary's downtown or along the edge.

While the system was introduced in 2011, Vine said its use was made mandatory on building projects five storeys or greater in Calgary's downtown and Beltline area as of Jan. 1, 2014.

De Jong said it seems to be making a difference.

"We're getting a lot fewer issues from active construction sites," he said.

For example, calls regarding construction debris have dropped from 32 to 24 over the past year.

"It brings a lot greater awareness to safety issues and what wind can do. It has averted possible incidents and, potentially, even a tragedy from occurring, because there's more visibility and awareness of pending situations," said Vine.

De Jong said RWDI has also recently come out with a city-wide version of the system – the Calgary Wind Warning app –  available for owners and contractors to purchase across several platforms.

While this app is not as detailed as the site-specific AWFS, it does provide forecasts on a quadrant-by-quadrant basis in Calgary.

These quadrant-specific wind warnings are relevant for home builders and lowrise building construction.

De Jong said RWDI achieves specificity with Envision because it creates models of projects under construction and inserts them into an overall model of downtown Calgary.

RWDI tests the impact of forecasted winds – gathered from several sources – on specific construction projects by placing the models into a wind tunnel to discover how different wind speeds will impact individual buildings at different heights, given their unique surroundings.

"They took the technology they were using in the oil and gas industry for plume prediction and combined that with their understanding of winds at heights to come up with this," de Jong explained, adding RWDI also designs exterior cladding systems for tall towers around the world.

"That it's site specific and height specific is what makes this system really ground breaking," de Jong re-iterated, adding that Calgary has discussed the technology with other jurisdictions, including New York City.

He said the AWFS is paid for by allotting a small percentage of building permit fees towards its usage and maintenance, which results in a cost of a few hundred dollars to a contractor.

The contractor and RWDI also enter into their own contract so RWDI can, literally, include the new project into its forecasting model.

"This brings safety into a simple format," said de Jong.

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