Davenport Criteria
Davenport (Isyumov & Davenport) Criteria
The Davenport criteria, sometimes referred to as the Isyumov & Davenport criteria, were developed in the mid-1970s by A. G. Davenport and N. Isyumov in Canada.
They were one of the earliest systematic attempts to quantify pedestrian wind comfort and safety, and remain a historic benchmark in wind engineering.
The framework uses the Beaufort wind force scale to set threshold wind speeds and applies an exceedance probability of ~1.5% (roughly “once per week”) as the limit of tolerability for each activity.
Compared to Lawson’s 1978 criteria, Davenport allows higher wind speeds for the same activities, but at a stricter frequency of occurrence.
Davenport Comfort Categories
| Category | Wind Speed Threshold | Exceedance Probability | Typical Activity | Color |
|---|---|---|---|---|
| A | ≤ 3.6 m/s (Beaufort 3) | ≤ 1.5% | Long exposure sitting (cafés, outdoor seating, amphitheaters) | |
| B | ≤ 5.3 m/s (Beaufort 4) | ≤ 1.5% | Short sitting or standing (bus stops, plazas, entrances) | |
| C | ≤ 7.6 m/s (Beaufort 5) | ≤ 1.5% | Strolling, casual walking | |
| D | ≤ 9.8 m/s (Beaufort 6) | ≤ 1.5% | Brisk walking, commuting | |
| E | > 9.8 m/s | > 1.5% | Uncomfortable for most activities |
Davenport Safety Categories
| Safety Class | Wind Speed Threshold | Exceedance Probability | Effect | Color |
|---|---|---|---|---|
| Safe | ≤ 15.1 m/s | ≤ 0.01% (~1 hour/year) | Conditions considered safe for all pedestrians | |
| Dangerous | > 15.1 m/s | > 0.01% (~1 hour/year) | Unsafe – risk of pedestrians being toppled or losing balance |