Guides / Climate & Microclimate
Wave Dynamics GuidesWind Microclimate Assessments Explained
How wind microclimate is assessed for tall buildings: Lawson comfort criteria, CFD modelling and wind tunnels, and mitigation such as canopies and planting.
In Short
A wind microclimate assessment predicts how a new building changes wind conditions at street level, on balconies and in public spaces, and whether they will be comfortable and safe for their intended use. It is usually needed for tall or large buildings, where downdraughts and funnelling can create windy conditions.
- Tall buildings can push faster upper-level winds down to street level.
- Comfort is judged against criteria such as the Lawson criteria.
- Assessed using computational fluid dynamics (CFD) or wind tunnel testing.
- Mitigation includes canopies, screens, planting and changes to massing.
Why Wind Matters
When wind hits a tall building, part of it is deflected down the face of the building and accelerates around corners and through gaps. This can make entrances, footpaths, terraces and balconies uncomfortable or, in extreme cases, unsafe. Planning policy for taller buildings in Ireland and the UK expects these effects to be assessed.
Comfort and Safety Criteria
The Lawson criteria classify locations by how often certain wind speeds are exceeded, matching each area to activities such as sitting, standing, strolling or walking. A separate safety criterion flags conditions strong enough to be a risk to pedestrians and cyclists.
How It Is Assessed
CFD modelling simulates wind flow around a 3D model of the proposed building and its surroundings for a range of wind directions, combined with local weather data. It is well suited to testing design options early. Wind tunnel testing on physical scale models may be used for very tall or complex schemes.
Typical Mitigation
- Canopies and podiums to deflect downdraughts away from footpaths.
- Recessed entrances and screens on corners.
- Dense, evergreen planting and porous screens in public spaces.
- Changes to massing, such as setbacks or rounded corners.
Frequently Asked Questions
When is a wind assessment needed?
Usually for buildings significantly taller than their surroundings, or large schemes with public spaces, as required by local policy or the planning authority.
Can balconies be assessed?
Yes. Balconies and roof terraces are typically assessed against the sitting or standing criteria for summer use.
This guide gives general information and is not a substitute for project-specific advice. Requirements change, so always check the current regulations, guidance and your planning conditions. Ask our team about your project.
Jon Maguire (BSc Hons MIOA) brings over 8 years of expertise in acoustic consultancy, specialising in environmental acoustics with a focus on 3D modelling, assessments, and detailed design for industrial, commercial, and energy projects. He has lead noise assessments for key clients while thriving in multidisciplinary environments. Jon’s diplomatic communication skills are ideal for stakeholder consultation.
Jack is a Field Engineer at Wave Dynamics, supporting the delivery of environmental monitoring and acoustic consultancy services through detailed on-site fieldwork. He has hands-on experience in noise monitoring, vibration monitoring, and dust monitoring across a variety of infrastructure, construction, and environmental projects. Jack is involved in the setup, operation, and maintenance of monitoring equipment, ensuring accurate data collection in line with relevant standards and project requirements. He works closely with consultants and project teams, providing reliable field support that underpins high-quality assessments and reporting.
Aidan is the Director for all U.K Operations and has worked in multiple industries including for clients in the UK and internationally operating in the residential, industry, healthcare, education, and construction sectors.
