How To Calculate Your Required DP Ratings?

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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