London changes skyscraper building regulations in fear of high winds in the streets

The city of London has tightened the rules on the construction of skyscrapers to prevent creating an urban microclimate in the surrounding streets.

 A network of high buildings can create air currents that move downwards and wind tunnels strong enough to be a concern about the safety of pedestrians and cyclists.

The new regulations, presented as "UK's first wind microclimate guidelines", will require the examination of the wind effects on the streets and will be applied to any building reaching over 25 meters. "With the number of tall buildings in the Square Mile growing, it is important that the knock-on effects of new developments on wind at street-level are properly considered," Alastair Moss, head of the London's planning and transportation committee, stated.

Since the construction of the 20 Fenchurch Street skyscraper (also known as the Walkie-Talkie due to its unique shape) in 2014, strong winds have affected the streets below. Apparently, the building creates a wind tunnel that has knocked pedestrians down and destroyed shop signs. Nevertheless, London authorities state that the new rules do not derive from a particular incident.

"Anywhere where a tall building goes up, you find that somewhere you could be previously cycling happily, there is a wall of wind. You can suddenly be really struggling. In the rush to put up tall buildings, no one has been thinking about what it means for aspirations to make cycling and walking simpler and safer. It's great that someone has started now," Roger Geffen, the policy director at Cycling UK, a UK membership organization supporting cyclists, commented.

According to the new guidelines, for structures between 25-50 meters, computational analyses or wind-tunnel testing will need to be conducted before being approved. Moreover, for those that exceed 50 meters, both procedures will be carried out.

The new rules will re-establish the wind conditions currently considered tolerable. From now on, winds that exceed 29km/h will be classified as "uncomfortable". Moreover, in areas with restaurants and coffee shops the limit will be reduced to 9 km/h.

Currently, the new regulations will be applied within the City of London, however, they could be implemented in a larger region in the future. "We hope these groundbreaking guidelines can create a blueprint for others by delivering safer, more enjoyable streets that meet the evolving needs of this great City," Mr. Moss, stated.