20 CAR § 880-1113 – Dispensing units

(a) All containers mounted on tractors used for dispensing anhydrous ammonia shall be equipped to comply with the rules as described in 20 CAR § 880-1105 with the exception of the requirement for the excess flow check valve in the liquid outlet and the vapor return valve.

(b) Containers used for dispensing purposes shall not exceed two hundred fifty (250) water-gallon capacity. FLOW CHART Minimum required rate of discharge in cubic feet per minute of air at 120 percent of the maximum permitted start-to-discharge pressure for safety relief valves to be used on Anhydrous Ammonia containers.

				Surface
Surface Area	Flow Rate	Surface Area	Flow Rate	Area	Flow Rate
Sq. Ft	C.F.M. Air	Sq. Ft	C.F.M. Air	Sq. Ft	C.F.M. Air
20	258	185	1600	900	5850
25	310	190	1640	950	6120
30	360	195	1670	1000	6380
35	408	200	1710	1050	6640
40	455	210	1780	1100	6900
45	501	220	1850	1150	7160
50	547	230	1920	1200	7410
55	591	240	1980	1250	7660
60	635	250	2050	1300	7910
65	678	260	2120	1350	8160
70	720	270	2180	1400	8410
75	762	280	2250	1450	8650
80	804	290	2320	1500	8900
85	845	300	2380	1550	9140
90	885	310	2450	1600	9380
95	925	320	2510	1650	9620
100	965	330	2570	1700	9860
105	1010	340	2640	1750	10090
110	1050	350	2700	1800	10330
115	1090	360	2760	1850	10560
120	1120	370	2830	1900	10800
125	1160	380	2890	1950	11030
130	1200	390	2950	2000	11260
135	1240	400	3010	2050	11490
140	1280	450	3320	2100	11720
145	1310	500	3620	2150	11950
150	1350	550	3910	2200	12180
155	1390	600	4200	2250	12400
160	1420	650	4480	2300	12630
165	1460	700	4760	2350	12850
170	1500	750	5040	2400	13080
175	1530	800	5300	2450	13300
180	1570	850	5590	2500	13520

Surface Area = Total outside surface area of container in square feet. When 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 X outside diameter in feet X 3.1416. 2. Cylindrical container with semi-ellipsoidal heads: Area = (Overall length in feet + 0.3 outside diameter in feet) X outside diameter in feet X 3.1416. 3. Spherical containers: Area = Outside diameter in feet square X 3.1416. Flow Rate - C.F.M. Air = Cubic feet per minute of air required at standard conditions, 60_ F and atmospheric pressure (14.7 PSIA) The rate of discharge may be interpolated for intermediate values of surface area.