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Wind zones map - Italy

What are the Italian wind zones according to Eurocode 1 ?

On the map of the national annex, the Italian area is divided by region (and sometimes by province) into nine wind zones identified from 1 to 9. The islands (with the exception of Sicily and Sardinia) and open sea form zone 9.

Zone 1 2 3 4 5 6 7 8 9
Fundamental value of the basic wind velocity vb,0 25m/s 25m/s 27m/s 28m/s 28m/s 28m/s 28m/s 30m/s 31m/s
Increased wind velocity above elevation a0 1000m 750m 500m 500m 750m 500m 1000m 1500m 500m
Eurocodes - Wind zones map - Italy (2010-2023) Wind zoning of Italy (2010-2023)

How to adjust the basic wind velocity for each direction of wind and according to return period in Italy ?


A variation have to be considered with the probability factor cprob.

No reduction can be considered with the directional factor cdir = 1.0.

You should also take in account the effect of the roughness of the terrain (vegetation / urbanization) and the effect of orography (terrain relief) to accurately determine the peak velocity pressure for each wind direction.

Which are the terrain categories in Italy ?

In Italy, the exposure categories are calculated from :

Roughness classes

  • D - Category D - country area Category D - airport Area free of obstacles (open countryside, airports, agricultural areas, pastures, swampy or sandy areas, snowy or icy surfaces, sea, lakes, ...)
  • C - Category C - area with trees, fences Category C - area with houses, walls Areas with widespread obstacles (trees, houses, walls, fences, ...); areas with roughness not attributable to classes A, B, D.
  • B - Category B - wooded areas Category B - urban, suburban, industrial areas Urban (non-class A), suburban, industrial and wooded areas.
  • A - Category A - downtown Area in which at least 15% of the surface is covered with buildings and their average height exceeds 15m.

Exposure categories for each wind zones

Zones 1 to 5
Distance to the shoreline from -2km to 0km from 0km to 10km from 10km to 40km more than 40km
Elevation - from 0m to 500m from 500m to 750m more than 750m
A - IV IV V V V
B - III III IV IV IV
C - * III III IV IV
D I II II II III **
*Category II in zone 1 to 4, category III in zone 5.
**Category III in zone 2 to 5, category IV in zone 1.
Zone 6
Distance to the shoreline from -2km to 0km from 0km to 10km from 10km to 40km more than 40km
Elevation - from 0m to 500m more than 500m
A - III IV V V
B - II III IV IV
C - II III III IV
D I I II II III
Zones 7 and 8 Zone 9
Distance to the shoreline from -2km to -0.5km from -0.5km to 0km on land Distance to the shoreline at sea on land
A - - IV A - I
B - - IV B - I
C - - III C - I
D I II * D I I
*Category II in zone 8, category III in zone 7.

Example of results given by the software

See the features of Eurocodes Zoning for wind analysis in Italy
Available in English/French, otherwise «Google Translate»!

B1 - Localization

Italian flag
10.5188° , 43.7455°
Large map
Simple map
56011 Calci, Toscana

B2 - Elevations

Elevation map to calculate orography factor
Coordinates 10.5181°, 43.7303° 10.5198°, 43.7596° 10.5198°, 43.7596° 10.5179°, 43.7901°
Elevations 60m 798m 798m 109m
Obstacle effective height H 738m 689m
Slope actual length Lu / Ld 3261.4m 3379.8m
Slope angle Φ 22.6% 20.4%
Horizontal distance site/top x 1571.5m
Elevation at the place of construction 216m

B3 - Building

common structure
50years
10.0m
15°

B4 - Terrain categories

Terrain map
Sectors 1 2 3 4
Roughness classes C C B B
Radius R of the angular sector : 1000m
Coastline map of Italy
Sectors 1 2 3 4
Sector definition from 330° to 60° from 60° to 150° from 150° to 240° from 240° to 330°
Distance to shore > 100 km > 100 km 21.3 km 19.5 km
Exposure category III III III III

C1 - Snow UNI EN 1991-1-3 Appendice nazionale 24/09/2010

III (sk,0 = 0.6kN/m2)
Pisa,Toscana
sk,216m = 0.613 kN/m2

s50years = 0.613 kN/m2

C2 - Wind UNI EN 1991-1-4 Appendice nazionale 24/09/2010

3 (vb,0 = 27.0m/s)
Pisa, Toscana
Sectors 1 2 3 4
Sector definition from 330° to 60° from 60° to 150° from 150° to 240° from 240° to 330°
Value of the basic wind velocity from the map vb,0,map 27.0m/s
Elevation above which wind velocity increases a0 500m
Fundamental value of the basic wind velocity vb,0 27.0m/s
Shape parameter K 0.138
Exponent n 1.0
Annual probability of exceedence p 0.02
Probability factor cprob 1.0
Directional factor cdir 1.0 1.0 1.0 1.0
Basic wind velocity vb 27.0m/s 27.0m/s 27.0m/s 27.0m/s
Reference roughness length z0,II 0.05m
Roughness length z0 0.1m 0.1m 0.1m 0.1m
Terrain factor kr 0.2 0.2 0.2 0.2
Height above ground z 10.0m
Minimum height zmin 5.0m 5.0m 5.0m 5.0m
Roughness factor cr(z) 0.921 0.921 0.921 0.921
Obstacle type isolated hills
Exposure type downwind - upwind -
Factor depending on the type and dimensions of the obstacle s 0.444 0.0 0.282 0.0
Orography factor* co(z) 1.181 1.0 1.128 1.0
Mean wind velocity vm(z) 29.4m/s 24.9m/s 28.0m/s 24.9m/s
Turbulence factor kl 1.0 1.0 1.0 1.0
Standard deviation of the turbulence σv 5.4m/s 5.4m/s 5.4m/s 5.4m/s
Turbulence intensity Iv(z) 0.184 0.217 0.193 0.217
Air density ρ 1.25kg/m3
Exposure factor ce(z) 2.706 2.138 2.532 2.138
Peak velocity pressure qp(z) 1233.0N/m2 974.0N/m2 1153.8N/m2 974.0N/m2
Peak wind velocity for Serviceability Limit States vp(z),SLS 159.9km/h 142.1km/h 154.7km/h 142.1km/h
Peak wind velocity for Ultimate Limit States vp(z),ULS 195.8km/h 174.1km/h 189.4km/h 174.1km/h
* The orography factor is calculated for a well individualized obstacle (an emergent zone compared to a general ground without marked relief)