Wind Comfort Calculators

Wind Speed & Assessment
Wind Speed at Assessment Height
m/s
Beaufort Description
effects
Dynamic Pressure
Pa
Lawson Comfort Assessment
Overall Comfort Status
Lawson Criteria
ActivityThreshold (m/s)Current SpeedStatus
Beaufort Scale
Forcem/s RangeDescriptionLikely Effects at Pedestrian Level
Lawson Criteria (Lawson 2001, updated Stathopoulos 2009): frequency-based criteria for pedestrian wind comfort in built environments. Wind speed at height z: V(z) = V(10) × (z/10)^alpha. Dynamic pressure: q = 0.5 × 1.25 × V². Wind Microclimate Assessment (WMA) recommended for major developments.
Reference Speed
Assessment Heights
Speed at 1.75m (pedestrian)
m/s
Speed at 10m (standard)
m/s
Power Law Exponent α
exponent
Dynamic Pressure at 10m
Pa
Height Profile
Height (m)Wind Speed (m/s)Dynamic Pressure (Pa)Beaufort Force
Windbreak Specification
Auto from type
Site & Wind
Direction it faces (N=0)
Direction wind comes FROM
Wind Speed at Target
m/s
Effective Shelter Distance
×H downwind
Angle of Incidence
° (0=perpendicular)
Protected Area Estimate
Lawson Comfort Status (Walking)
Shelter Zone Profile
Distance from WindbreakReduction %Speed Remaining (m/s)
Maximum shelter occurs at optimal porosity ~30–40% — solid barriers create turbulence behind them. Maximum shelter extends to 10–20×H downwind. Perpendicular wind (0° incidence) = maximum effect; at 45°, effect reduces ~30%; at 90° (parallel), minimal shelter. MAAS-OSTERLANEY model used.
Structure Parameters
Net Wind Force Fw
kN
Overturning Moment
kNm
Peak Gust Pressure
kPa (×1.5 factor)
Cladding / Fixings Design Pressure
kPa
Eurocode 1 / BS EN 1991-1-4: qp = 0.5 × ρ × vb² × Ce. Fw = Cf × qp × Aref × (1−porosity). OTM = Fw × centre-of-pressure height. Gust factor ≈ 1.5×mean for cladding design. Always verify with structural engineer for permanent/public structures. Fence posts: check foundation moment resistance (see Structural & Safety Calculator).
Canyon Geometry
0=parallel, 90=perpendicular
H/W Aspect Ratio
ratio
Accelerated Speed in Canyon
m/s
Pedestrian Level Speed (1.75m)
m/s
Corner Acceleration Factor
worst-case factor
Flow Regime
Lawson Status (Walking)
Climatic Inputs
Air temp + 5–20°C in sun
Human Factors
UTCI — Universal Thermal Climate Index
°C
Comfort Hours Estimate
hrs/yr
Overall Comfort
status
PET Comfort Category
UTCI Thermal Stress
Recommendation
PET Scale
PET (°C)CategoryPerceptionStress Level
< 4°CVery coldExtreme cold stressVery strong
4–8°CColdCold stressStrong
8–13°CCoolModerate cold stressModerate
13–18°CSlightly coolSlight cold stressSlight
18–23°CComfortableNo thermal stressNone
23–29°CSlightly warmSlight heat stressSlight
29–35°CWarmModerate heat stressModerate
35–41°CHotStrong heat stressStrong
> 41°CVery hotExtreme heat stressVery strong
PET (Hoppe 1999): Physiological Equivalent Temperature — air temperature in a reference environment producing the same thermal body core and skin temperature. Calculated via human body energy balance. UTCI: Universal Thermal Climate Index. Fanger’s PMV model also applicable for controlled semi-outdoor environments. Output is an indicative estimate.