City Corporation launches UK’s first planning ‘wind guidelines’ to keep cyclists and pedestrians comfortable and safe

The City of London Corporation has today published the UK’s first wind microclimate guidelines for new development proposals in the Square Mile. Going further than established thinking, the set of guidelines raises the benchmark for acceptable wind conditions in the City, putting the comfort and safety of cyclists and pedestrians first.

The guidelines provide a more robust framework for assessing the impact of planning applications on wind conditions. They will ensure what were previously acceptable ‘business walking conditions’ are now reclassified as ‘uncomfortable’, and to be avoided other than in exceptional circumstances of limited public access.

For the first time in the UK, effects on cycling comfort and safety arising from wind microclimate are also considered. Wind can, in extreme cases, destabilise or push cyclists into the path of vehicles. By testing roadways as well as pavements through wind tunnel studies or computer simulations, it is expected that the more robust assessment will lead to a safer and more comfortable urban environment for all – in line with greater use of the City’s streets for cycling, walking and other outdoor activities.

The needs of more vulnerable groups in society are also prioritised, ensuring greater consideration outside areas such as schools or elderly people’s homes.

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 these state-of-the-art guidelines. The guidelines build on complex research previously undertaken by RWDI for the City Corporation, which was awarded the Mayor’s Award for Planning Excellence at the London Planning Awards 2017.

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

The new guidelines are in line with the City of London Corporation’s ambitious Transport Strategy and draft City Plan (to be finalised in the coming months), which aim to prioritise pedestrians, promote cleaner and healthier ways to travel, and increase the amount of high-quality public space in the City.

As the first wind microclimate guidelines ever published in the UK, the criteria could form the basis for national or international standards for wind microclimate studies.

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.”

Notes to editors

The City of London Corporation is the governing body of the Square Mile dedicated to a vibrant and thriving City, supporting a diverse and sustainable London within a globally-successful UK. www.cityoflondon.gov.uk

To read more about the wind guidelines please visit our Design Guidance site.