1 - S T R E N G T H A N D E F F E C T S O F W I N D O N B E AU F O R T S C A L E
Degree Class*
Load (N/mq)
Knots
Km/h
m/s
Envir. conditions
Effects of wind
0
0
< 40
0-1
0-1
< 0,3
Calm
Smoke rises vertically
1
0
< 40
1-3
1-5
0,3-1,5
Light air
Direction of wind shown by smoke drift, but not by weather vanes
2
0
< 40
4-6
6-11
1,6-3,3
Light breeze
Wind felt on face, ordinary vanes moved by wind
3
0
< 40
7-10
12-19
3,4-5,4
Gentle breeze
Leaves and small twigs in constant motion
4
1
40
11-16
20-28
5,5-7,9
Moderate breeze
Raises dust and loose paper; small branches are moved
5
2
70
17-21
29-38
8-10,7
Fresh breeze
Small trees begin to sway
6
3
110
22-27
39-49
10,8-13,8
Strong breeze
Large branches in motion; umbrellas used with difficulty
7
> 3
> 110
28-33
50-61
13,9-17,1
Strong wind
Whole trees in motion; inconvenience felt when walking against wind
8
> 3
> 110
34-40
62-74
17,2-20,7
Fresh gale
Branches break off trees; generally impedes progress
9
> 3
> 110
41-47
75-88
20,8-24,4
Strong gale
Tiles come off roofs
10
> 3
> 110
48-55
89-102
24,5-28,4
Whole gale
Trees uprooted
11
> 3
> 110
56-63
103-117
28,5-32,6
Storm
Serious damage to buildings
12
> 3
> 110
>64
>118
> 32,7
Hurricane
Immense damage
* According to the UNI EN 13561 standard
TABLES
2 - 04.2011
CORRADI S.P.A. - USER MANUAL - EXYL
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