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Pedestrian Wind Comfort and Safety
Israeli Pedestrian Wind Comfort and Safety Criteria (IS 5281)

Israeli Pedestrian Wind Comfort and Safety Criteria (IS 5281)

In Israel, analyses of pedestrian wind comfort and safety conditions are mandated for new — and in certain cases, existing — developments. These criteria, part of the Israel Green Building Standards (IS 5281: Sustainable Building), are used to assess the wind environment in the vicinity of developments.

They address both comfort for various pedestrian activities and safety concerns related to excessive gusts. The guidelines assume open-air conditions and that pedestrians are dressed appropriately for the season (thermal comfort is evaluated separately).

IS 5281 Comfort Categories

Wind Comfort CategoryExceedance Frequency @ 6 m/sExceedance Frequency @ 9 m/sDescriptionColor
Seating Zones≤ 20%≤ 5%Calm/light breezes, ideal for outdoor restaurants and seating
Entrances≤ 25%≤ 10%Gentle breezes suitable for entrances, bus stops, waiting areas
Streets & Parking≤ 35%≤ 15%Moderate winds, acceptable for leisurely walking or parking areas
Business / Commercial Areas> 35%> 15%Windy conditions, nuisance for activities, mitigation typically needed

IS 5281 Safety Criteria

Wind Safety RatingWind Speed ThresholdExceedance ProbabilityDescriptionColor
Pass20 m/s< 0.1%Excessive gusts occur rarely. Suitable for sitting and long stays
Limited Risk20 m/s> 0.1%“Danger Zone” for sensitive activities; extended stays problematic
Exceeded20 m/s> 0.2%Unsafe – gusts exceed acceptable limits, affecting balance and footing

Notes

  • Vgust (Gust Equivalent Wind Speed): Calculated using an assumed α (alpha coefficient) of 3.
  • Vmean (Horizontal Mean Wind Speed): Average wind speed measured horizontally.
  • VRMS (Root-Mean-Square of Mean Wind Speed): Captures variability in mean wind.
  • Comfort Criterion: Wind conditions are considered acceptable for a category if the predicted exceedance does not surpass the 6 m/s threshold.