355 IAC 3-9-1 Minimum rate of discharge for pressure relief valves

Sec. 1. The minimum required rate of discharge in cubic feet per minute of air at one hundred twenty percent (120%) of the maximum permitted start-to-discharge pressure for pressure relief valves to be used on containers other than those constructed in accordance with DOT specifications shall be as follows: Surface Area Flow Rate Square Feet CFM Air 20 258 25 310 30 360 35 408 40 455 45 501 50 547 55 591 60 635 65 678 70 720 75 762 80 804 85 845 90 885 95 925 100 965 105 1,010 110 1,050 115 1,090 120 1,120 125 1,160 130 1,200 135 1,240 140 1,280 145 1,310 150 1,350 155 1,390 160 1,420 165 1,460 170 1,500 175 1,530 180 1,570 185 1,600 190 1,640 195 1,670 200 1,710 210 1,780 220 1,850 230 1,920 240 1,980 250 2,050 260 2,120 270 2,180 280 2,250 290 2,320 300 2,380 310 2,450 320 2,510 330 2,570 340 2,640 350 2,700 360 2,760 370 2,830 380 2,890 390 2,950 400 3,010 450 3,320 500 3,620 550 3,910 600 4,200 650 4,480 700 4,760 750 5,040 800 5,300 850 5,590 900 5,850 950 6,120 1,000 6,380 1,050 6,640 1,100 6,900 1,150 7,160 1,200 7,400 1,250 7,660 1,300 7,910 1,350 8,160 1,400 8,410 1,450 8,650 1,500 8,900 1,550 9,140 1,600 9,380 1,650 9,620 1,700 9,860 1,750 10,090 1,800 10,330 1,850 10,560 1,900 10,800 1,950 11,030 2,000 11,260 2,050 11,490 2,100 11,720 2,150 11,950 2,200 12,180 2,250 12,400 2,300 12,630 2,350 12,850 2,400 13,080 2,450 13,300 2,500 13,520 (1) Surface Area = Total outside surface area of a container in square feet. When the surface area is not stamped on the name plate or when the marking is not legible, the area can be calculated by using one (1) of the following formulas: (A) Cylindrical container with hemispherical heads: Area = overall length in feet times outside diameter in feet times 3.1416 (B) Cylindrical container with other than hemispherical heads: Area = (overall length in feet plus 0.3 outside diameter in feet) times outside diameter in feet times 3.1416 (C) Spherical container: Area = outside diameter in feet squared times 3.1416 (2) Flow Rate CFM Air = Cubic feet per minute of air required at standard conditions, sixty (60) degrees Fahrenheit and atmospheric pressure (14.7 psia). The rate of discharge may be interpolated for intermediate values of surface area. For containers with a total outside surface area greater than two thousand five hundred (2,500) square feet, the required flow rate can be calculated using the formula, Flow Rate CFM Air = 22.11 A0.82, where A = outside surface area of the container in square feet.