MASTER
Digital Anemometer An anemometer measures the speed of moving air, most often wind speed. You will be using it to calculate the speed of air moving through a vent.
Operating Instructions 1. Turn the anemometer on by depressing and holding the “mode” button. The device should power up in a few seconds. 2. To change the units for measuring wind speed, depress and hold the “mode” button until the speed unit flashes. 3. Depress “set” to get the desired wind speed unit. 4. To change from ºC to ºF or vice -versa, remove the yellow cover from the device, turn it over, and use a push-pin or straightened paper clip to depress the “C/F” button on the back. 5. The device will also show the Beaufort Scale for the wind speed, as a series of pointed blocks stacking upon each other.
BEAUFORT NUMBER
NAME OF WIND
LAND CONDITIONS
WIND SPEED (MPH)
0
Calm
Smoke rises vertically
Less than 1
1
Light air
2
Direction of wind shown by smoke drift but not by wind vanes
1-3
Light breeze
Wind felt on face, leaves rustle, ordinary wind vane moved by wind
4-7
3
Gentle breeze
Leaves and small twigs in constant motion, wind extends light flag
8 - 12
4
Moderate breeze
Wind raises dust and loose paper, small branches move
13 - 18
5
Fresh breeze
Small trees and leaves start to sway
19 - 24
6
Strong breeze
Large branches in motion, whistling in wires, umbrellas used with difficulty
25 - 31
7
Near gale
Whole trees in motion, inconvenient to walk against wind
32 - 38
8
Gale
Twigs break from trees, difficult to walk
39 - 46
9
Strong gale
Slight structural damage occurs, shingles and slates removed from roof
47 - 54
10
Storm
Trees uprooted, considerable structural damage occurs
55 - 63
11
Violent storm
Widespread damage
64 - 63
12
Hurricane
Widespread damage, devastation
What is the Beaufort Scale? In 1805, Sir Francis Beaufort of the Royal Navy developed the scale to help sailors estimate wind speed for settings sails based on visible effects of winds. The scale describes wind effects seen on land or at sea and assigns a value of 0 to 12 according to the force applied by the wind. The higher the number, the stronger (faster) the wind.
Greater than 72
Portrait by Stephen Pearce of Sir Francis Beaufort; c. 1855-1856, oil painting
26
©2021 The NEED Project Wonders of Offshore Wind Teacher Guide
www.NEED.org
