MINIMUM FLOW RATES

Pressure relief valves for excessive heat or fire protection used on containers covered by parts 1513.0300 to 1513.0380 and 1513.1000 to 1513.1070 must be constructed to discharge at not less than the rates required in this part before the pressure is in excess of 121 percent of the maximum allowable working pressure of the container. Relief protection for any other reason, except refrigerated storage, must use ASME UG-125 through UG-136. Surface Area, Sq.Ft. Flow Rate, CFM Air Surface Area, Sq.Ft. Flow Rate, CFM Air Surface Area, Sq.Ft. Flow Rate, CFM Air 20 258 185 1,600 900 5,850 25 310 190 1,640 950 6,120 30 360 195 1,670 1,000 6,380 35 408 200 1,710 1,050 6,640 40 455 210 1,780 1,100 6,900 45 501 220 1,850 1,150 7,160 50 547 230 1,920 1,200 7,410 55 591 240 1,980 1,250 7,660 60 635 250 2,050 1,300 7,910 65 678 260 2,120 1,350 8,160 70 720 270 2,180 1,400 8,410 75 762 280 2,250 1,450 8,650 80 804 290 2,320 1,500 8,900 85 845 300 2,380 1,550 9,140 90 885 310 2,450 1,600 9,380 95 925 320 2,510 1,650 9,620 100 965 330 2,570 1,700 9,860 105 1,010 340 2,640 1,750 10,090 110 1,050 350 2,700 1,800 10,330 115 1,090 360 2,760 1,850 10,560 120 1,120 370 2,830 1,900 10,800 125 1,160 380 2,890 1,950 11,030 130 1,200 390 2,950 2,000 11,260 135 1,240 400 3,010 2,050 11,490 140 1,280 450 3,320 2,100 11,720 145 1,310 500 3,620 2,150 11,950 150 1,350 550 3,910 2,200 12,180 155 1,390 600 4,200 2,250 12,400 160 1,420 650 4,480 2,300 12,630 165 1,460 700 4,760 2,350 12,850 170 1,500 750 5,040 2,400 13,080 175 1,530 800 5,300 2,450 13,300 180 1,570 850 5,590 2,500 13,520 Surface Area = Total Outside Surface Area of Container in Square Feet. If the surface area is not stamped on the nameplate or when the marking is not legible, the area can be calculated by using one of the following formulas: (1) Cylindrical container with hemispherical heads Area = overall length in feet times outside diameter in feet times 3.1416. (2) 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. (3) Spherical container Area = outside diameter in feet squared times 3.1416. Flow Rate--CFM Air = cubic feet per minute of air required at standard conditions, 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 total outside surface area greater than 2,500 square feet, the required flow rate can be calculated using the formula, Flow Rate CFM Air = 22.11 A 0.82 where A = outside surface of the container in square feet. CONVERSION FACTORS: ft 2 x 0.092 903 = m 2 CFM x 0.028 317 = m 3 /min ft x 0.304 8 = m