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42 WISCONSIN ADMINISTRATIVE CODE
<br /> Ind 8
<br /> and emergency venting devices shall be not less than that derived from
<br /> Table 8.19-8 except as provided in par. (f) or (g).Such device may be a
<br /> self-closing manhole cover,or one using long bolts that permit the cover ,
<br /> to lift under internal pressure,or an additional or larger relief value or .
<br /> values.The wetted area of the tank shall be calculated on the basis of 55 .
<br /> percent of the total exposed area of a sphere or spheroid,75 percent of
<br /> the total exposed area of a horizontal tank and the first 30 feet
<br /> abovegrade of the exposed shell area of a vertical tank.
<br /> Table 8.19-8
<br /> Wetted Area Versus Cubic Feet Free Air Per Hour* .
<br /> (14.7 psia and 60° F.)
<br /> Sq.Ft. CFH Sq.Ft. CFH Sq.Ft. CFH
<br /> 20 21,100 200 211,000 1,000 524.000
<br /> 30 31,600 250 239,000 1,200 557,000 •
<br /> 40 42,100 300 265,000 1,400 587,000
<br /> 50 52,700 350 288,000 1.600 614,000 .
<br /> 60 63,200 400 312,000 1.800 639,000
<br /> 70 73,700 500 354,000 2,000 662.000
<br /> 80 84,200 600 392,000 2,400 704,000 -
<br /> 90 94,800 700 428,000 2,800 742,000
<br /> 100 105,000 800 462.000 and over
<br /> 120 126,000 900 493,000
<br /> 140 147,000 1,000 524,000
<br /> 160 168.000
<br /> 180 190,000
<br /> 200 211,000
<br /> 'interpolate for intermediate values.
<br /> Table 8.19-9
<br /> Wetted Area Versus Cubic Free Air Per Hour
<br /> Wetted Area Over 2,800 Sq. Ft.and Pressures Over 1 psig
<br /> (14.7 psia and 60° F.)
<br /> Sq.Ft. CFH Sq.Ft. CFH
<br /> 2,800 742,000 9,000 1,930,000
<br /> . 3,000 786.000 10,000 2,110,000 •
<br /> 3,500 892.000 15,000 2.940,000
<br /> 4,000 995.000 20,000 3,720,000 •
<br /> 4,500 1,100.000 25,000 4,470,000 •
<br /> 5,000 1,250,000 30,000 5,190,000
<br /> 6,000 1,390.000 35.000 5,900,000
<br /> 7,000 1,570,000 40.000 6,570,000 •
<br /> 8,000 1,760,000
<br /> (e) [2-2.5.5] For tanks and storage vessels designed for pressures over
<br /> 1 psig,the total rate of venting shall be determined in accordance with
<br /> Table 8.19-8 except that when the exposed wetted area of the surface is
<br /> greater than 2,800 sq.ft.,the total rate of venting shall be in accordance
<br /> with Table 8.19-9 or calculated by the following formula:
<br /> CFH = 1,107 A 0.82
<br /> Where CFH = venting requirement, in cubic feet of free
<br /> air per hour.
<br /> A = exposed wetted surface, in square feet.
<br /> Register,March,1982,No.315
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