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Wind zones map - France

What are the French wind zones according to Eurocode 1 ?

On the map of the national annex, the French metropolitan area is divided into four wind zones identified from 1 to 4. Amendment A3, published in April 2019, replaces the division by cantons into a division by municipalities.

Zone 1 2 3 4
Fundamental value of the basic wind velocity vb,0 22m/s 24m/s 26m/s 28m/s
Eurocodes - Wind zones map - Metropolitan France (2019-2021) Wind zoning of Metropolitan France (2019-2021)
The French overseas departments, overseas territories and overseas collectivities each have a specific basic wind velocity.
Zone French Guiana Mayotte Island Martinique Island Reunion Island Guadeloupe Island
Fundamental value of the basic wind velocity vb,0 17m/s 30m/s 32m/s 34m/s 36m/s
Basic wind velocity for overseas departments
Zone New Caledonia Wallis and Futuna Saint Martin Saint Barths Saint Pierre and Miquelon
Fundamental value of the basic wind velocity vb,0 36m/s 41.2m/s 36m/s 36m/s 36m/s
Basic wind velocity for overseas territories and overseas collectivities

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


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

When the wind comes from a direction where the probability of occurrence of strong winds is less, a reduction can be considered with the directional factor cdir.

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 France ?

Particularity concerning New Caledonia

The terrain categories have been transposed to Caledonian landscapes. The reference to terrain category IV is removed and categories 0 to III of standard NF EN 1991-1-4 are illustrated by the photographs below :

Source: RCNC

Example of results given by the software

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

B1 - Localization

French flag
3.5332° , 45.7153°
741482m , 6512993m
Large map
Simple map
D 304A, 63120 Sauviat, Auvergne-Rhône-Alpes

B2 - Elevations

Elevation map to calculate orography factor
Distances / Direction At the place of construction 500m 1000m
North 436 m 360m 407m
Northeast 405m 465m
East 456m 473m
Southeast 419m 446m
South 449m 476m
Southwest 432m 411m
West 360m 468m
Northwest 403m 452m

B3 - Building

monumental building
100years
15.0m
80°

B4 - Terrain categories

Terrain map
Sectors 1 2 3 4
Categories IIIa IV IV IV
Radius R of the angular sector : 593m

C1 - Snow NF EN 1991-1-3/NA (may 2007) + A1 (july 2011)

A2 (sk,0 = 0.45kN/m2)
PUY-DE-DOME (63)
sk,436m = 0.686 kN/m2

s100ans = 0.774 kN/m2

sad = 1.0kN/m2

C2 - Wind NF EN 1991-1-4/NA (march 2008) + A1 (july 2011) + A2 (september 2012) + A3 (april 2019)

2 (vb,0 = 24.0m/s)
PUY-DE-DOME (63)
1
Sectors 1 2 3 4
Sector definition from 35° to 125° from 125° to 215° from 215° to 305° from 305° to 35°
Fundamental value of the basic wind velocity vb,0 24.0m/s
Shape parameter K 0.2
Exponent n 0.5
Annual probability of exceedence p 0.01
Probability factor cprob 1.038
Directional factor cdir 0.7 1.0 1.0 1.0
Basic wind velocity vb 17.4m/s 24.9m/s 24.9m/s 24.9m/s
Reference roughness length z0,II 0.05m
Roughness length z0 0.2m 1.0m 1.0m 1.0m
Terrain factor kr 0.209 0.234 0.234 0.234
Height above ground z 15.0m
Minimum height zmin 5.0m 15.0m 15.0m 15.0m
Roughness factor cr(z) 0.904 0.635 0.635 0.635
Orography factor* co(z) 1.0 1.0 1.0 1.0
Mean wind velocity vm(z) 15.8m/s 15.8m/s 15.8m/s 15.8m/s
Turbulence factor kl 0.97 0.854 0.854 0.854
Standard deviation of the turbulence σv 3.544m/s 4.989m/s 4.989m/s 4.989m/s
Turbulence intensity Iv(z) 0.225 0.315 0.315 0.315
Air density ρ 1.225kg/m3
Exposure factor ce(z) 2.102 1.292 1.292 1.292
Peak velocity pressure qp(z) 392.0N/m2 491.5N/m2 491.5N/m2 491.5N/m2
Peak wind velocity for Serviceability Limit States vp(z),SLS 91.1km/h 102.0km/h 102.0km/h 102.0km/h
Peak wind velocity for Ultimate Limit States vp(z),ULS 111.5km/h 124.9km/h 124.9km/h 124.9km/h
* Here, the orography factor is calculated according to Procedure 1, for an orography consisting of obstacles of various heights and shapes. This type of orography is the most frequently encountered.However, if the building is in a case of orography consisting of well individualized obstacle (isolated hills and ridges or cliffs and escarpments) the orography factor must be calculated according to the procedure 2. According to EN 1991-1-4 §4.3.3(1), the calculated orography factor (1.018) is not taken into account because it does not increase wind velocities by more than 5%.

C3 - Seism Code of the Environment - Article D563-8-1 (09/01/2015) + JORF n°0248 of 24/10/2010 text N°5

3 (1.1m/s2)
Sauviat, Puy-de-Dome (63)
A seismic analysis is required for this building.