Image: Dreamstime/Zoltan Gabor
Skyscraper developers will have to show their buildings won’t create a ‘wind tunnel effect’ that endangers pedestrians and cyclists, after the City of London published new planning guidelines.
The City of London Corporation claimed that the new wind microclimate guidelines are the first of their kind ever published in the UK, and could form the basis for national or international standards for wind microclimate studies.
They “put the comfort and safety of cyclists and pedestrians first” by providing a more robust framework for assessing the impact of planning applications on wind conditions, the Corporation said.
The guidelines now reclassify what were previously acceptable “business walking conditions” as “uncomfortable” and state that they are to be avoided other than in exceptional circumstances of limited public access.
The Corporation warned that in extreme cases, the wind microclimate created by skyscrapers could also destabilise or push cyclists into the path of vehicles and that roadways as well as pavements would have to be tested through wind tunnel studies or computer simulations.
The City Corporation collaborated with Ender Ozkan of RWDI, a specialist engineering consultancy, and sought input from members of the wind engineering community in preparing the guidelines, which build on complex research previously undertaken by RWDI for the City Corporation.
The guidelines will also:
- Require that wind impacts are tested at the earliest point of a scheme’s design development (e.g. height and massing) to avoid the need to retrofit wind mitigation measures
- Ensure more micro-level assessments of wind directions is carried out in wind tunnel testing
- Apply a new rigorous code of practice in the use of Computational Fluid Dynamics (CFD) techniques
- Require the commissioning of two separate consultants, one to carry out wind tunnel testing and the other CFD, and interrogate any discrepancies between both sets of results
- Assess the variation of mean and gust wind speed and height
Alastair Moss, chair of the Planning and Transportation Committee, said: “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. These guidelines mark another significant step that the City Corporation is taking to put cyclists and pedestrians at the heart of planning in the Square Mile, prioritising their safety and experience.
“From the Transport Strategy to the City Plan, we are ensuring that our streets are a comfortable and pleasant place to live, work and visit.
“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.”
