The four main pedestrian wind comfort assessment methods are NEN 8100, the Lawson criteria, the Davenport criteria, and the Melbourne criteria. In practice, NEN 8100 and Lawson dominate — NEN 8100 is the legal standard in the Netherlands, while Lawson is widely used in the UK, Canada, and on international projects. The choice of method depends on where your project is located and what the permit authority requires. Below, we break down how each method works and when to use which.
How do the four main wind comfort methods differ from each other?
The four main pedestrian wind comfort methods — NEN 8100, Lawson, Davenport, and Melbourne — all assess how often wind speeds at pedestrian level exceed a threshold that makes an activity uncomfortable or unsafe. What separates them is how they define those thresholds, which activities they cover, and how they express the probability of discomfort.
NEN 8100 is the Dutch standard. It measures how often wind speed at eye height (1.75 m) exceeds 5 m/s, then assigns a class from A to E based on that exceedance probability. Class A means wind is rarely a problem; class E means it is uncomfortable most of the time. The standard also has a separate wind danger threshold at 15 m/s.
The Lawson criteria take a different approach. Instead of one speed threshold for all activities, Lawson assigns a specific wind speed to each type of activity — sitting, standing, strolling, walking briskly — and states that this speed should not be exceeded more than 5% of the time. This makes Lawson more granular in how it links wind conditions to the actual use of a space.
The Davenport criteria and Melbourne criteria are older frameworks that follow a similar logic to Lawson but use slightly different speed thresholds and probability limits. They are less commonly required today but still appear in academic research and some international project briefs.
The table below summarises the key differences:
| Method | Primary market | Comfort threshold | Danger threshold |
|---|---|---|---|
| NEN 8100 | Netherlands | 5 m/s, classes A–E | 15 m/s, exceedance probability |
| Lawson | UK, Canada, international | Per activity (4–10 m/s), max 5% | >15 m/s or >20 m/s, 0.025% |
| Davenport | International / academic | Per activity, hourly mean | Varies |
| Melbourne | International / academic | Per activity, gust-based | Varies |
When is NEN 8100 the required standard for wind assessment?
NEN 8100 is the required standard whenever a wind study is part of a permit application in the Netherlands. Dutch municipalities and the Environment and Planning Act (Omgevingswet) reference NEN 8100 as the benchmark for assessing pedestrian wind comfort around buildings and area developments. If your project needs a wind study to obtain an omgevingsvergunning, NEN 8100 is not optional — it is the legal framework.
In practice, NEN 8100 applies to most new high-rise buildings, urban redevelopment projects, and large-scale masterplans in the Netherlands. The standard uses meteorological input data from the NPR 6097 dataset (covering 1963–2002), which is prescribed by law for permit procedures. This means the wind climate used in the calculation is fixed, making results comparable across projects and defensible in front of permit authorities.
One important nuance: NEN 8100 does not distinguish between summer and winter. It produces a year-round average exceedance probability, which means it can sometimes underestimate how uncomfortable a location feels on a cold winter afternoon. That said, the standard’s five-class system (A through E) gives a clear, structured outcome that planners and municipalities can act on directly.
Our team has over 21 years of experience delivering NEN 8100 assessments for projects across the Netherlands, working with municipalities, developers, and architects who need reports that hold up under regulatory scrutiny. We know what permit authorities look for — and we make sure the output is clear enough to present directly to planners without needing a translator.
What are the Lawson criteria and where are they used?
The Lawson criteria are a pedestrian wind comfort framework developed in the UK that links specific wind speed thresholds to specific activities. Each activity has its own limit: wind speeds above 4 m/s should not occur more than 5% of the time in a sitting area, above 6 m/s for standing, above 8 m/s for strolling, and above 10 m/s for walking. If any of these thresholds are exceeded more than 5% of the time, the location is considered uncomfortable for that activity.
Lawson is the dominant standard in the UK and Canada, and it is widely used on international projects where no local norm has been prescribed. For wind danger, Lawson uses two thresholds: speeds above 15 m/s occurring more than 0.025% of the time pose a risk to vulnerable users; speeds above 20 m/s at the same frequency are considered dangerous for everyone.
Compared to NEN 8100, Lawson uses higher speed thresholds for most activities. Research from Rotterdam’s urban wind study showed that this can lead to more optimistic results in practice — several locations in the city that are clearly uncomfortable in real life were classified as acceptable under Lawson, while NEN 8100 flagged them correctly. This does not make Lawson a poor standard; it simply means that the two frameworks are calibrated differently and are not directly interchangeable.
We apply the Lawson criteria for projects in the UK, Gibraltar, the Middle East, and other international contexts where it is the expected or required framework. Our wind engineering services cover both standards, so you get the right assessment for the right market without having to brief two different consultants.
How does CFD simulation compare to physical wind tunnel testing?
CFD (Computational Fluid Dynamics) simulation and physical wind tunnel testing are both reliable methods for pedestrian wind comfort assessment, but they suit different project types. Wind tunnel testing uses a physical scale model in a controlled airflow environment and is well suited to individual buildings or smaller masterplans. CFD runs the same calculations virtually, using a 3D model built from geodata, and scales far more easily to large urban areas.
For city-wide or district-scale assessments, a physical wind tunnel is simply not practical — the model would need to be enormous, and the cost and time involved would be prohibitive. CFD handles these scales well. In the Rotterdam urban wind study, for example, the CFD model covered a core radius of 500 metres with a total domain diameter of 8,000 metres and included more than 583 million computational cells. That level of detail is only achievable through simulation.
For individual buildings, both methods are valid and produce comparable results. Wind tunnel testing offers a physical reference that some clients and authorities find reassuring. CFD gives you faster iteration — if a design changes, updating the model takes hours rather than weeks. It also produces colour-coded maps and visualisations that are easy to share with clients, planners, and permit authorities without requiring technical interpretation.
The choice between the two often comes down to project scale, timeline, and what the permit authority expects. Increasingly, CFD is accepted as the primary method for both individual buildings and large-scale assessments, provided the simulation setup follows recognised standards such as NPR 6097. You can read more about how we approach this on our CFD simulations page.
Which wind comfort method should be used for a given project?
The right wind comfort method depends primarily on where your project is located and what the local permit authority requires. For projects in the Netherlands, NEN 8100 is the standard — there is no choice to make. For projects in the UK, Canada, or most international contexts, Lawson is the expected framework. If no local standard applies, Lawson is generally the most widely recognised international option.
Beyond geography, a few other factors shape the decision:
- Project scale: Large area developments benefit from CFD-based assessments regardless of which comfort standard applies. Wind tunnel testing is more practical for individual buildings.
- Type of spaces being assessed: If the project includes a mix of sitting areas, pedestrian routes, and public squares, Lawson’s activity-specific thresholds give more targeted guidance. NEN 8100’s class system gives a cleaner overview for permit purposes.
- Stage in the design process: An early-stage feasibility study has different needs than a final permit submission. A quick CFD scan can flag wind risks before they become expensive design problems; a full NEN 8100 or Lawson report is what you need when the design is locked.
- Municipal requirements: Some Dutch municipalities have specific policies on top of NEN 8100 — for example, requiring class A or B in certain public spaces. Knowing these local requirements before you start saves time later.
If you are unsure which method applies to your project, the fastest route is to ask a specialist early. Discovering that you need a different standard — or a more extensive study — after the design is finalised is one of the most common and avoidable causes of delay in permit applications. The Actiflow website gives a good overview of the services and expertise available across different project types.
How Actiflow helps with pedestrian wind comfort assessment
We help architects, developers, structural engineers, and municipalities get the right wind comfort assessment — delivered on time, in the right format, and built to hold up under regulatory review. Whether your project is a single high-rise in Amsterdam or a district-wide masterplan in the UK, we match the method to the project and the permit requirement.
- NEN 8100 assessments for permit applications in the Netherlands, with output that municipalities can act on directly
- Lawson-based assessments for UK, international, and cross-border projects
- CFD simulations that produce colour-coded maps and visualisations — clear enough to present to clients and planners without technical translation
- Wind tunnel testing for individual buildings where a physical reference is preferred or required
- Large-scale urban wind studies, including experience with city-wide assessments like the one we carried out for the city of Rotterdam
- Early-stage design advice to flag wind risks before they require costly revisions
- Fast turnaround — for regular clients, we set everything aside to start the next day if the project demands it
Curious how we can help with pedestrian wind comfort? Feel free to contact us. We would be happy to discuss your project and help you find the right engineering solution. You can also find out more about our team and background on our about us page.
