NEN 8100 (Netherlands)
Back to Pedestrian Wind Comfort and Safety
NEN 8100 (Netherlands) uses a fixed wind-speed limit and classifies how often it is exceeded. Comfort uses the hourly mean wind speed. Safety uses a gust-adjusted wind speed.
Pedestrian Wind Comfort
Comfort uses a single 5 m/s hourly-mean wind-speed threshold. Classes A–E depend on how frequently that speed is exceeded. Walking means passing through; strolling means walking slowly or lingering.
| Category | Threshold wind speed (hourly mean) | Exceedance probability | Activity | Color |
|---|---|---|---|---|
| A | 5 m/s | < 2.5% | Good for walking, strolling and sitting | |
| B | 5 m/s | ≥ 2.5% and < 5% | Good for walking and strolling; moderate for sitting | |
| C | 5 m/s | ≥ 5% and < 10% | Good for walking; moderate for strolling; poor for sitting | |
| D | 5 m/s | ≥ 10% and ≤ 20% | Moderate for walking; poor for strolling and sitting | |
| E | 5 m/s | > 20% | Poor for all three activities |
Pedestrian Wind Safety
ArchiWind assesses NEN 8100 pedestrian wind safety using how often a gust-adjusted wind speed exceeds 15 m/s. The exceedance probability bands below define its three risk classes.
The gust-adjusted speed is U_NEN = U_mean + 1.5 × σ_u, where U_mean is the local mean wind speed and σ_u ≈ sqrt(2k/3) is the standard deviation of the wind-speed fluctuations, estimated from the simulated turbulent kinetic energy k in the same way as for the Lawson gust estimate. This is more conservative than the mean wind speed alone. The factor 1.5 is the gust allowance ArchiWind uses for this check.
| Category | Threshold wind speed (gust-adjusted) | Exceedance probability | Meaning | Color |
|---|---|---|---|---|
| A | 15 m/s | < 0.05% | No risk | |
| B | 15 m/s | ≥ 0.05% and < 0.30% | Limited risk | |
| C | 15 m/s | ≥ 0.30% | Dangerous |
No risk is the map label for results below the defined NEN risk threshold. Limited risk is acceptable only for passing through, not for strolling or sitting. Dangerous is unsuitable for all three activities.
For an annual result, 0.05% is about 4 hours and 0.30% about 26 hours.