Effer 265 - Page 25

Wind
Force
Average wind speed (*)
Characteristics
m/s km/h mph Wind type
2
on the face, while leaves begin to rustle
and weather vanes can start to move.
1.6 - 3.3 6 - 11 4 - 7
3 3.4 - 5.4 12 - 19 8 - 12
Moderate
wind
Leaves and twigs in continuous
movement. Small branches begin to
move. Dust and paper begin to move over
the ground.
4 5.5 - 7.9 20 - 28 13 - 18
5a 8.0 - 10.1 29 - 36 19 - 22 Intermediate conditions between 4 and 5.
5 10.2 - 10.7 37 - 38 23 - 24
Fairly
strong wind
Small leaved branches make swaying
movements; crested waves form on lakes
and canals.
6 10.8 - 13.8 39 - 49 25 - 31 Strong wind
Large branches move; you can hear
the wind whistling in telephone wires;
umbrellas can only be held with difficulty.
7 13.9 - 17.1 50 - 61 32 - 38
Severe
wind
Entire trees move; the wind causes
difficulty when you walk into it.
8 17.2 - 20.7 62 - 74 39 - 46
Stormy
wind
Twigs break off, and walking is difficult.
9 20.8 - 24.4 75 - 88 47 - 54 Storm
Causes superficial damage to buildings
(chimney pots, roof tiles, and TV antennae
are blown off).
10 24.5 - 28.4 89 - 102 55 - 63
Severe
storm
Uprooted trees; considerable damage to
buildings etc (occurs infrequently on land).
11 28.5 - 32.6 103 - 117 64 - 72
Very severe
storm
Causes extensive damage (occurs very
infrequently on land).
12 > 32.6 > 118 > 73 Hurricane
IMPORTANT
Wind force Permitted boom system position and crane configuration
5a Boom system in any position (crane in service and out of service)
5 Boom system below 45° from the horizontal (cranes in service)
6 Boom system below 45° from the horizontal (crane without load and out of service)
NOTE
•
(*) Speed according to EN 13000. Beaufort scale.
•
Refer to the manual of the anemometer for more information about the precise method of measurement.
•
Refer to Table B for crane/load heights over 10 meters (H > 10m).
Safety precautions and warnings
EFFER 265-315-395-525 Progress 2.0 CE 25