An ill wind building
Proposed highrise for downtown Halifax could create unfavourable gusts
By CHRIS LAMBIE Business Editor
Wed. Feb 17 - 4:53 AM
NEW DEVELOPMENTS proposed for downtown Halifax could make for some windy walking.
"Large buildings can impact the local wind velocities experienced at pedestrian level," says a study that investigated the impact a 20-storey building would have on wind patterns in the downtown core.
The proposed building is to be con-structed at the Discovery Centre site at 1595 Barrington St.
When air hits a building’s flat surface, it is deflected in all four directions, according to the report prepared by an engineer from SimuTech Group.
"Since the downwash effect due to south, west and east winds is predicted to be low, only the northern winds in the winter months may create downwash issues," says the study of the Discovery Centre project.
"Northerly winds may hit the large north face and deflect it downwards towards the Sackville Street sidewalk. The northwest edge of this face has a curved profile that may assist the northerly wind to pass around the building on this side, helping to mitigate the downwash. However there is also a concave inwards curve that may ‘catch’ the wind, directing more downwards."
The rounded western corner of the building will "more than likely cause the winds to wrap around the building rather than be deflected down to pedestrian levels," says the report.
In the design, the 60-metre-tall structure’s "lower facade protrudes out from the main building structure in this region. This is expected to provide some protection to the sidewalk below as it will redirect a portion of the downwash outwards, across the street. The buildings north of Sackville will offer little resistance to the wind and thus will not help reduce this northerly downwash effect."
The building, proposed by developer Frank Medjuck, won’t have any entrances on Sackville Street and the downwash might affect wind patterns on the other side of the street, says the study.
"The only other predictable effect which may influence pedestrian level winds is a funnelling effect due to south winds and north-westerly winds," it says.
"Since both sides of Granville Street will have highrise structures (existing and 1595 Barrington), the flow may channel and accelerate down Granville Street."
Wind could also create problems for another proposed Barrington Street building. Lou Reznick’s Starfish Properties plans to tear down the Roy building and recreate the Barrington facade with a 17-storey tower behind it on Granville Street.
"With the new building in place, wind conditions along Sackville Street are expected to be comfortable for walking in the summer and uncomfortable in the winter," it says.
The building would shelter sidewalks on Sackville Street from northwest winds. But easterly winds could channel along the street and northerly winds could accelerate around the proposed development’s southeast corner, says the study.
The study recommends wind tunnel testing for a detailed evaluation of the project.
"Wind control measures ranging from provision of landscaping to architectural additions and building massing changes may be considered to reduce wind speeds along Sackville Street," says the study.
"With the refined wind control measures in place, reduced wind activity can be expected along Sackville Street."
(
clambie@herald.ca)