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TITLE 3 DIVISION OF INDUSTRIAL SAF—y 68.19 -� dNFIRED PRESSURE VESSEL SAFE •ro-oRDERS (Aaglator 77. No. 13-57.77) (f) All pumps and compressors used for the transfer of anhydrous ammonia shall be suitable for this service and shall be equipped with a pressure-actuated bypass valve and/or other acceptable device to prevent pressure in the transfer equipment of more than 400 psi unless the piping system is specifically designed for higher pressures. In no case shall safety relief valves used for this purpose be set to open at pressures of less than 325 psi or more than 400 psi. (1) Pumps shall be designed for at least 250p.S.i.working pressure. Positive displacement pumps shall have, installed off the discharged port, a constant differential relief valve discharging into the suction port of the pump through a line of sufficient size to carry the full capacity of the pump at relief valve setting, which setting and instal- lation shall be according to the pump manufacturer's recommenda- tions. On the discharge side of the pump, before the relief valve line, there shall be installed a pressuregage graduated from 0 to 400 p.s.i. Plant piping shall contain shutoff valves located as close as practical to pump connections. (2) Compressors used for transferring or refrigerating ammonia shall be recommended for ammonia service by the manufacturer. Compressors shall be designed for at least 250 p.s.i. working pres- sure. Plant piping shall contain shutoff valves located as close as practical to compressor connections. A relief valve large enough to discharge the full capacity of the compressor shall be connected to the discharge before any shutoff valve. Compressors shall have pressure gages at suction and discharge graduated to at least one and one-half times the maximum pressure that can be developed. Adequate means, such as drainable liquid trap, shall be provided on the compressor suction to minimize the entry of liquid into the com- pressor. Where necessary to prevent contamination, an oil separator shall be provided on the discharge side of the compressor. (g) The filling densities for containers that are not refrigerated shall not exceed the following: Percent Percent Type of Container By Weight By Volume Uninsulated................................................................ 56 82 87.5 • Uninsulated (see 509(h) ) ..................................... 57 83.5 Insulated ............................. ...................................... D.O.T. In accordance with D.O.T. Regulations (h) Uninsulated containers may be charged 87.5 percent by volume provided the temperature of the anhydrous ammonia being charged is determined to be not lower than 30° F. or provided the charging of the container is stopped at the first indication of frost or ice formation on its outside surface and is not resumed until such frost or ice has disap- peared.