Code of Colorado Regulations
1200 - Department of Agriculture
1202 - Inspection and Consumer Services Division
8 CCR 1202-5 - STORAGE AND HANDLING OF ANHYDROUS AMMONIA
Section 2 - DESIGN OF ANHYDROUS AMMONIA SYSTEMS

2.1.1. Above-ground uninsulated containers shall have a reflective surface maintained in good condition. White is recommended for painted surfaces, but other light reflecting colors are acceptable.

2.2.1. Where concentrations of ammonia in air in excess of 16% by volume are likely to be encountered, electrical equipment and wiring shall be of a type specified by and be installed in accordance with National Electrical Code, NFPA 70 (ANSI-C1), for Class I, Group D locations.

2.3.1. System nameplates, when required, shall be permanently attached to the system so as to be readily accessible for inspection and shall include markings as prescribed in 2.3.2.

2.3.2. Each container or system covered in Sections 7, 9, 10 and 11 shall be marked as follows:

2.3.3. All main operating valves on permanently installed containers having a capacity of over three thousand water gallons shall be identified to show whether the valve is in liquid or vapor service. The recommended method of identification may be legend or color code as specified in 2.3.3.1 or 2.3.3.2.

2.4.1. All appurtenances shall be designed for not less than the maximum working pressure of that portion of the system on which they are installed.

2.4.2. All connections to containers except safety relief devices, gauging devices, or those fitted with a No. 54 drill size orifice shall have shut-off valves located as close to the container as practicable.

2.4.3. The emergency shutoff valve shall be placed in the liquid line internally or externally to the container.

2.4.4. Excess flow valves where required by these Rules shall close automatically at the rated flows of vapor or liquid as specified by the manufacturer. The connections and line including valves and fittings being protected by an excess flow valve shall have a greater capacity than the rated flow of the excess flow valve.

2.4.5. Liquid level gauging devices that require bleeding of the product to the atmosphere and which are so constructed that outward flow will not exceed that passed by a No. 54 drill size opening need not be equipped with excess flow valves.

2.4.6. Openings from containers or through fittings attached directly on containers to which pressure gauge connections are made need not be equipped with excess flow valves if such openings are not larger than No. 54 drill size.

2.4.7. Excess flow and back pressure check valves where required by these Rules shall be located inside of the container or at a point outside as close as practicable to where the line enters the container. In the latter case, installation shall be made in such manner that any undue stress beyond the excess flow or back pressure check valve will not cause breakage between the container and the valve.

2.4.8. Excess flow valves shall be designed with a by-pass, not to exceed a No. 60 drill size opening to allow equalization of pressures.

2.4.9. Shut-off valves provided with an excess flow valve shall be designed for proper installation in a container connection so that the excess flow valve will close should the shut-off valve break.

2.4.10. All excess flow valves shall be plainly and permanently marked with the name or trademark of the manufacturer, the catalog number, and the rated capacity.

2.4.11. Each liquid connection used to fill a permanent storage container shall be fitted with a backflow check valve.

2.4.12. All appurtenances to any permanent storage container shall be protected from tampering and mechanical damage, including damage from vehicles. Each manually controlled valve that, if open, would allow ammonia to be transferred or released, shall be kept locked when unattended and during nonbusiness hours.

2.5.1. All piping, tubing and fittings shall be made of material suitable for anhydrous ammonia service.

2.5.2. All piping, tubing and fittings shall be designed for a pressure not less than the maximum pressure to which they may be subjected in service.

2.5.3. All piping shall be well supported and provision shall be made for expansion and contraction.

2.5.4. Piping used on non-refrigerated systems shall be at least ASTM A-53 Grade B Electric Resistance Welded and Electric Flash Welded Pipe or equal. Such pipe shall be at least Schedule 40 when joints are welded, or welded and flanged. Such pipe shall be at least Schedule 80 when joints are threaded. Brass, copper, or galvanized steel pipe or tubing shall not be used.

2.5.5. All metal flexible connections for permanent installations shall have a minimum working pressure of 250 psig (safety factor of 4). For temporary installations, hose meeting the requirement of 2.6 may be used.

2.5.6. Cast iron fittings shall not be used but this shall not prohibit the use of fittings made specifically for ammonia service of malleable or nodular iron such as specification ASTM A47 or ASTM A395.

2.5.7. Provisions shall be made for expansion, contraction, jarring, vibration, and for settling.

2.5.8. Adequate provisions shall be made to protect all exposed piping from physical damage that might result from moving machinery, the presence of automobiles or trucks, or any other undue strain that may be placed upon the piping.

2.5.9. Joint compounds shall be resistant to ammonia.

2.5.10. After assembly, all piping and tubing shall be tested and proved to be free from leaks at a pressure not less than the normal operating pressure of the system.

2.6.1. Hoses used in ammonia service and subject to container pressure shall conform to the specification set forth in Appendix B of this Rule, which are based on The Rubber Manufacturers Association and The Fertilizer Institute "Hose Specifications for Anhydrous Ammonia".

2.6.2. Hose subject to container pressure shall be designed for a minimum working pressure of 350 psig and a minimum burst pressure of 1750 psig. Hose assemblies, when made up, shall be capable of withstanding a test pressure of 500 psig.

2.6.3. Hose and hose connections located on the low pressure side of flow control or pressure reducing valves on devices discharging to atmospheric pressure shall be designed for the maximum low side working pressure. All connections shall be designed, constructed, and installed so that there will be no leakage when connected.

2.6.4. Where liquid transfer hose is not drained of liquid upon completion of transfer operations, such hose shall be equipped with an approved shut-off valve at the discharge end. Provision shall be made to prevent excessive hydrostatic pressure in the hose. (See Rule 2.7.16.).

2.6.5. On all hose one-half inch O.D. and larger, used for the transfer of anhydrous ammonia liquid or vapor, there shall be etched, cast, or impressed at five-foot intervals the following information:

2.6.6. Each hose shall be replaced before or upon the expiration of the manufacturer's removal date.

2.6.7. A hose shall be removed from service prior to the manufacturer's removal date if a visual examination reveals any of the following:

2.7.1. Every container used in systems covered by Sections 7, 9, 10 and 11 shall be provided with one or more safety relief valves of the spring-loaded or equivalent type. The discharge from safety relief valves shall be vented away from the container, upward and unobstructed to the atmosphere. All safety relief valve discharge openings shall have suitable rain caps that will allow free discharge of the vapor and prevent the entrance of water. Provision shall be made for draining condensate which may accumulate. The rate of the discharge shall be in accordance with the provisions of Appendix A of this Rule.

2.7.2. Container safety relief valves shall be set to start-to-discharge as follows, based on the design pressure of the container:

* NOTE: A RELIEF VALVE MANUFACTURER'S TOLERANCE OF PLUS 10% IS PERMITTED.

2.7.3. Safety relief devices used in systems covered by Sections 7, 9, 10 and 11 shall be constructed to discharge at not less than the rates required in 2.7.1 before the pressure is in excess of 120% (not including the 10% tolerance referred to in 2.7.2) of the maximum permitted start-to-discharge pressure setting of the device.

2.7.4. Safety relief valves shall be so arranged to minimize the possibility of tampering. If the pressure setting adjustment is external, the relief valves shall be provided with means for sealing the adjustment.

2.7.5. Shut-off valves shall not be installed between the safety relief valves and the containers or systems described in Sections 7, 9, 10 and 11, except that a shut-off valve may be used where the arrangement of this valve is such as always to afford required capacity flow through the relief valves.

NOTE: The above exception is made to cover such cases as a three-way valve installed under two safety relief valves, each of which has the required rate of discharge and is so installed as to allow either of the safety relief valves to be closed off, but does not allow both safety valves to be closed off at the same time. Another exception to this may be where two separate relief valves are installed with individual shut-off valves. In this case, the two shut-off valve stems shall be mechanically interconnected in a manner which will allow full required flow of one safety relief valve at all times. Still another exception is a safety relief valve manifold which allows one valve of two, three, four or more to be closed off and the remaining valve or valves will provide not less than the rate of discharge shown on the manifold nameplate.

2.7.6. Safety relief valves shall have direct communication with the vapor space of the container.

2.7.7. Each safety relief valve used with systems described in Sections 7, 9, 10 and 11 shall be plainly and permanently marked as follows:

2.7.8. Each pressure-relief valve shall be manufactured for use with anhydrous ammonia and be installed, maintained, and replaced according to the manufacturer's instructions.

2.7.9. Unless otherwise specified by the manufacturer, a pressure-relief valve shall not be used for more than five years after the date of manufacture of the pressure relief device.

2.7.10. Each safety valve shall be replaced if the valve meets any of the following conditions:

2.7.11. If moisture accumulation could occur in a vent, suitable provision shall be made to drain the moisture from the vent.

2.7.12. The flow capacity of the safety relief valve shall not be restricted by any connection to it on either the upstream or downstream side.

2.7.13. Vent pipes or tubing used to channel releases from safety relief valves shall not be restricted or smaller in size than the safety relief valve outlet connection.

2.7.14. Vent pipes may be connected and channeled into a common header if the cross-sectional area of the header is at least equal to the sum of the cross-sectional areas of each of the individual vent pipes.

2.7.15. The manufacturer or supplier of a safety relief valve manifold shall publish complete data showing the flow rating through the combined assembly of the manifold with safety relief valves installed. The manifold flow rating shall be determined by testing the manifold with all but one valve discharging. If one or more openings have restrictions not present in the remaining openings, the restricted opening or openings or those having the lowest flow shall be used to establish the flow rate marked on the manifold nameplate. The marking shall be similar to that required in 2.7.7 for individual valves.

2.7.16. A hydrostatic relief valve shall be installed between each pair of valves in the liquid ammonia piping or hose where liquid may be trapped so as to release into the atmosphere at a safe location.

2.7.17. Discharge from safety relief devices shall not terminate in or beneath any building.

2.8.1. Each container except those filled by weight shall be equipped with an approved liquid level gauging device.

2.8.2. All gauging devices shall be arranged so that the maximum liquid level to which the container is filled is readily determined (See 2.3.2.7).

2.8.3. Gauging devices that require bleeding of the product to the atmosphere such as the rotary tube, fixed tube, and slip tube devices, shall be designed so that the maximum opening of the bleed valve is not larger than No. 54 drill size unless provided with an excess flow valve. (This requirement does not apply to farm vehicles used for the application of ammonia, as covered in Section 11.)

2.8.4. Gauging devices shall have a design pressure equal to or greater than the design pressure of the container on which they are installed.

2.8.5. Fixed liquid level gauges shall be so designed that the maximum volume of the container filled by liquid shall not exceed 85% of its water capacity. The coupling into which the fixed liquid level gauge is threaded must be placed at the 85% level of the container. If located elsewhere, the dip tube of this gauge must be installed in such a manner that it cannot be readily removed.

2.8.6. Gauge glasses of the columnar type shall be restricted to stationary storage installations. They shall be equipped with shut-off valves having metallic hand wheels, with excess-flow valves, and with extra heavy glass adequately protected with a metal housing applied by the gauge manufacturer. They shall be shielded against the direct rays of the sun.