Tall buildings can deflect high-level wind down towards the ground, producing unpleasant and sometimes dangerous wind conditions in adjoining pedestrian areas. Architects, developers and planners must aim to provide a safe and comfortable wind microclimate in open-air pedestrian areas around buildings.

This BRE Digest brings together the latest information on wind environment around buildings to help building designers, planners, developers and building control officers. The general principles of wind flow around buildings and techniques for mitigating unacceptable wind speeds are discussed and advice is given on the methods and criteria for assessing pedestrian wind comfort. Guidance on the advantages and disadvantages of the different measurement techniques is also provided.

This Digest replaces Digest 390, which is now withdrawn.

Contents

Introduction

General principles of wind flow around buildings

- Effects of terrain

- Effects of building height

- Interaction between buildings

- Passageways

- Courtyards

- Effects of building shape

- Funnelling

- Street canyons and street geometry

- Entrances

Shelter behind fences and windbreaks

- General rules for wind shelter behind fences

General design guidance

- Do’s and don’ts

- Remedial measures for windy areas

Assessment of pedestrian comfort

Measurement techniques

- Wind tunnel testing

- Computational wind engineering

References