Support Wind Loading Data

Wind Loading Data

The UK map shows Basic Mean Hourly windspeeds with the contour lines defining areas A,B,C and D.                  
Windspeeds are shown at sea level and for every 100m increase in altitude, the Basic Mean Hourly windspeed increases by 10%, then giving the Site Mean Windspeed.

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Explanation of Town Location and Country Location used in the foundation sizes table in each product Foundations and Bolting Details page/PDF

Definition of 'Town location' - Town locations are locations within built up areas, with at least 15% of the surface built on, and/or on which the average height of buildings exceed 15m - for locations on outskirts that do not comply with this, 'Country location' for foundation sizes should be used.

Definition of 'Country location' - All areas, both coastal, up to 100m ASL and inland up to 200m ASL, that are not 'Town locations' (see table for higher altitudes).

  STANDARD FOUNDATIONS AREA A & B FOUNDATIONS UPTO 200m ASL AREA A,B & C FOUNDATIONS UPTO 350m ASL
Area Max Basic
Mean Hourly
Windspeed		 Height above
sea level for
foundation design		 Site mean
wind speed		 Actual wind velocity Height
above sea
level for
foundation
design		 Site
mean
wind
speed		 Actual
wind
velocity		 Height above
sea level for
foundation design		 Site mean
wind speed		 Actual wind velocity
A 22 m/s 100m 24.2 m/s 41.8 m/s (93 mph) 200m 26.4 m/s 45.6 m/s (102 mph) 350m 29.7 m/s 51.4 m/s (115 mph)
B 24 m/s 100m 26.4 m/s 45.6 m/s (102 mph) 200m 28.8 m/s 50 m/s (111 mph) 350m 32.4 m/s 56 m/s (125 mph)
C 25 m/s 150m 28.8 m/s 50 m/s (111 mph) N/A N/A N/A 350m 33.75 m/s 58.3 m/s (130 mph)
D 27 m/s 250m 33.75 m/s 58.3 m/s (130 mph) N/A N/A N/A N/A N/A N/A

Our standard designs are based on a mean hourly wind speed of 28.8 m/s (metres per second).This table shows the conversion from this mean hourly wind speed, to other internationally recognised wind speed measurements. Conversions are taken from the International Code Council 'International Building Code'.

Mean Hourly 3 Sec Gust 10 Min Average Fastest Mile
28.8 m/s 43.6 m/s 30.1 m/s 34.9 m/s
64.4 mph 97.5 mph 67.3 mph 78 mph
104.4 kph 158 kph 109 kph 126 kph


The actual wind velocity for a 28.8 m/s mean hourly wind speed = 50 m/s, 111 mph, 180 kph.