ARM 4.12.743. TABLES

(1) Table A - Rate of Discharge. TABLE A - RATE OF DISCHARGE Minimum required rate of discharge in cubic feet per minute (CFM) of air for safety relief valves. Discharge measured at 60 degrees F and atmospheric pressure (14.7 pounds per square inch) . Surface Area Sq. Ft. CFM Surface Area Sq. Ft. CFM Surface Area Sq. Ft CFM 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. 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 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 semi-ellipsoidal heads. Area = (overall length in feet plus 0.3 outside diameter in feet) times diameter in feet times 3.1416. (c) Spherical Container. Area = Outside diameter in Flow Rate SCFM Air = Cubic feet per minute of air required at standard conditions, 60 degrees F and atmospheric pressure (14.7 psia). The rate of discharge may be interpolated for intermediate values of surface area. For container with total outside surface area greater than 2,000 sq. ft., the required flow rate can be calculated using the formula, Flow Rate SCFM Air = 22.11A degrees .82, where A = Outside surface area of the container in square feet. (2) Table B - Guide for Selection of Materials for Refrigerated Ammonia Storage Tanks. TABLE B - GUIDE FOR SELECTION OF MATERIALS FOR REFRIGERATED AMMONIA STORAGE TANKS (a) Materials for shell and bottom for tanks of all design pressures shall have ductility at low temperatures equal to or superior to those listed in Table C. (b) When austenitic steels or non-ferrous materials are used, the code shall be used as a guide for temperature requirements. (c) Materials for nozzles, attached flanges, structural members which are in tension, and other such critical elements shall be selected for the design temperature. This selection shall be based on impact test requirements, or on probabilities such as used for the plate materials listed in Table C. (3) Table C - Minimum Material Requirements for Shells and Bottoms of Refrigerated Storage Tanks for Various Temperatures and Thicknesses. TABLE C - MINIMUM MATERIAL REQUIREMENTS FOR SHELLS AND BOTTOMS OF REFRIGERATED STORAGE TANKS FOR VARIOUS TEMPERATURES AND THICKNESSES Design Temperature Thickness Material Spec. Qualifications to be Added to the Basic Specification 65 F to 25 F, Incl. (See Note 1) Up to 1/2", Incl. Any approved steel with specified min.T.S. not exceeding 60,000 psi None Over 1/2" to 1", Incl. A-131B (or C) None Case 1256 None A-201 A & B FGP (Fine Grain Practice) Over 1" to 1 3/8", Incl. A-131C, Case 1256 None A-201 A&B None FGP Over 1 3/8" A-131C Normalized Case 1256 Normalized A-201 A & B FGP, Normalized Below 25 F to 5 F, Incl. (See Note 2) Up to 1/2", Incl. Case 1256 None A-201 A & B None Over 1/2" to 1 3/8", Incl. A-131B (to 1" max) FGP A-131C FGP Case 1256 FGP A-201 A & B (to 1" max) FGP, High Mang.* A-201 A & B (over 1") FGP, High Mang., Normalized Over 1 3/8" A-131C Normalized Case 1256 Normalized A-201 A & B FGP, High Mang., Normalized Below -5F to -30F (See note 3) Up to 1/2" Incl. Case 1256 FGP A-201 A & B FGP, High Mang. Over 1/2" to 1 3/8" Incl. A-131B (to 1" max) FGP, Normalized A-131C Normalized Case 1256 FGP, Normalized A-201 A & B FGP, High Mang., Normalized Over 1 3/8" A-300 Class 1 A-201 A & B Only *Manganese content of 0.70% to 1.0% is preferred in lieu of usual content of 0.80% maximum. Note 1: The design temperature shall be taken as the lower of the following: (a) The minimum temperature to which the tank contents will be refrigerated. (b) The minimum estimated tank shell temperature due to atmospheric temperatures, considering effectiveness of the insulation in keeping shell temperatures above expected minimum atmospheric temperature (if expected to be below the refrigerated temperature) . Note 2: For the thickness, temperature category approved steels include all of those listed in the API 12-C and API 620. Materials for vessels must comply with the requirements of the code and any additional requirements of the code and any additional requirements of this table. A-131 steel is not approved by ASME and some code cases have not been approved by local jurisdictions. All specific materials listed in table are satisfactory for all designs based on API 12-C or API 620. Note 3: For vessels constructed under the code with a design temperature below -20F., the impact requirements shall comply with Table B. (4) Table D - Repair Welding. TABLE D - REPAIR WELDING (a) All containers, piping and appurtenances which have contained or have been in direct contact with nitrogen fertilizer solutions containing ammonium nitrate must be thoroughly cleaned and washed with water (or steam) to eliminate all solid ammonium nitrate before welding or torch cutting may be attempted: Extreme caution should be taken before attempting to weld or torch cut any container when. ammonium nitrate could be trapped, for example, in the area between tank shell and a reinforcing plate. (b) All containers, piping, and appurtenances which have contained aqua ammonia (ammonium hydroxide) must be thoroughly vented and thoroughly washed with large quantities of water. After washing, they shall be filled with water to a level higher than area to be welded or repaired. (c) All containers shall be welded in accordance with the code. (5) Table E - Safety Pressure Relief Valves. TABLE E - SAFETY PRESSURE RELIEF VALVES (a) The rate of discharge shall be stamped on the safety relief valve in cubic feet of air per minute at: (1) 60 degrees F, (2) 14.7 pounds per square inch absolute, and (3) 120 percent of the stamped start-to-discharge setting. (b) Safety pressure relief valves in systems utilizing air compressors for the transfer of nitrogen fertilizer solutions shall have a minimum rate of discharge in cubic feet per minute of air of 120 percent of the compressor manufacturer's maximum rated capacity. (c) Safety pressure relief valves in systems utilizing pumps for transfer of nitrogen fertilizer solutions shall have a minimum rate of discharge of 120 percent of the liquid inflow rate. This can be computed as follows: Liquid pump maximum rated capacity in GPM times 0.16 equals vapor flow in CFM.