DP Rating WIND CONVERSION CALCULATION
Wind Conversion Calculation for DP Rating Follow these simple steps to calculate DP Ratings Step 1 • Choose the Zone. Zone 4 is in the center of the wall and 5 is within 4 ft. of the corner.
h
5
a
5
4
4
a
WALLS
5 5
a
a
a
Step 2 • Choose the size of the unit.
A 23 square foot specimen would be tested to the 20 Sq. Ft. pressure. An 18 square foot specimen would be tested to the 10 square foot pressure, etc... as described in the building code.
Wind Speed
Zone
Sq.Ft.
85 mph
90 mph
100 mph
105 mph
110 mph
4 4 4 4 5 5 5 5 4 4 4 4 5 5 5 5
10 20 50 10 20 50 10 20 50 10 20 50
13.0 12.4 11.6 11.1 13.0 12.4 11.6 11.1 25.9 24.7 23.2 22.0 25.9 24.7 23.2 22.0
-14.1 -13.5 -12.7 -12.2 -17.4 -16.2 -14.7 -13.5 -28.1 -26.9 -25.4 -24.2 -34.7 -32.4 -29.3 -26.9
14.6 13.9 13.0 12.4 14.6 13.9 13.0 12.4 28.1 26.8 25.2 23.9 28.1 26.8 25.2 23.9
-15.8 -15.1 -14.3 -13.6 -19.5 -18.2 -16.5 -15.1 -30.5 -29.2 -27.5 -26.3 -37.6 -35.1 -31.8 -29.2
18.0 17.2 16.1 15.3 18.0 17.2 16.1 15.3 30.4 29.0 27.2 25.9 30.4 29.0 27.2 25.9
-19.5 -18.7 -17.6 -16.8 -24.1 -22.5 -20.3 -18.7 -33.0 -31.6 -29.8 -28.4 -40.7 -38.0 -34.3 -31.6
19.8 18.9 17.8 16.9 19.8 18.9 17.8 16.9 35.3 33.7 31.6 30.0 35.3 33.7 31.6 30.0
-21.5 -20.6 -19.4 -18.5 -26.6 -24.8 -22.4 -20.6 -38.2 -36.7 -34.6 -33.0 -47.2 -44.0 -39.8 -36.7
21.8 20.8 19.5 18.5 21.8 20.8 19.5 18.5 37.8 36.1 33.9 32.2 37.8 36.1 33.9 32.2
-23.6 -22.6 -21.3 -20.4 -29.1 -27.2 -24.6 -22.6 -41.0 -39.3 -37.1 -35.4 -50.6 -47.2 -42.7 -39.3
100
100
150 mph
120 mph
125 mph
130 mph
140 mph
145 mph
40.5 38.7 36.2 34.4 40.5 38.7 36.2 34.4
-43.9 -42.1 -39.7 -37.8 -54.2 -50.5 -45.7 -42.1
100
100
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DP Rating WIND CONVERSION CALCULATION
(CONTINUATION FROM PAGE 1)
Step 3 • Choose your roof height and exposure.
Roof height is dimension H in the photo below and is taken from a point ∏ between the eve and the peak of the roof. Exposure typically, exposure B is 120 MPH and less and exposure C is 130 and higher.
20 MEAN ROOF HEIGHT 25 30 15
EXPOSURE
B
C
1.00 1.00 1.00 1.00 1.05 1.09 1.12 1.16 1.19 1.22
1.21 1.29 1.35 1.40 1.45 1.49 1.53 1.56 1.59 1.62
55 60 35 40 45 50
h
5
a
5
4
4
a
WALLS
5 5
a
a
a
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