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 7 - SYSTEMS UTILIZING STATIONARY, PIER-MOUNTED OR SKID-MOUNTED ABOVEGROUND OR UNDERGROUND

7.1.1. The minimum design pressure for non-refrigerated aboveground containers shall be 250 psig. [See.1.2.1.]

NOTE: U-68 and U-69 ASME Code containers with a design pressure of 200 psig are acceptable if recertified to 250 psig and equipped with safety relief valves set at 250 psig as permitted in 2.7.2.

7.2.1. Each filling connection shall be provided with combination back-pressure check valve and excess flow valve; one double or two single back-pressure check valves; or a positive shut-off valve in conjunction with either an internal back-pressure check valve or an internal excess flow valve.

7.2.2. All vapor and liquid connections, except safety relief valves and those specifically exempt in Rules 2.4.5 and 2.4.6 . shall be equipped with approved excess flow valves; or in lieu thereof, may be fitted with approved quick-closing internal valves which, except during operating periods, shall remain closed.

7.2.3. Each storage container shall be provided with a pressure gauge graduated from 0 to 400 psig. Gauges shall be designated for use in ammonia service.

7.2.4. All containers shall be equipped with an approved vapor return valve.

7.2.5. All containers shall be equipped with a fixed maximum liquid level gauge.

7.3.1. Every container shall be provided with one or more safety relief valves of spring-loaded or equivalent type and shall comply with the following:

7.3.2. The rate of discharge of spring-loaded safety relief valves installed on underground containers may be reduced to a minimum of 30 per cent of the rate of discharge specified in Appendix A of this Rule. Containers so protected shall not be uncovered after installation until the liquid ammonia has been removed. Containers which may contain liquid ammonia before being installed underground and before being completely covered with earth are considered aboveground containers when determining the rate of discharge requirements of the safety relief valves.

7.3.3. On underground installations where there is a probability of the manhole or housing becoming flooded, the discharge from vent lines shall be located above the high water level. All manholes or housings shall be provided with ventilated louvres or their equivalent, the area of such openings equaling or exceeding combined discharge areas of safety relief valves and vent lines which discharge their content into the manhole housing.

7.4.1. Containers installed aboveground shall be provided with substantial reinforced concrete footings and foundations or structural steel supports mounted on reinforced concrete foundations. In either case, the reinforced concrete foundations or footings shall extend below the established frost line and shall be of sufficient width and thickness to support the total weight of the containers and contents adequately. The foundation shall maintain the lowest point of the tank at not less than 18 inches above the ground. Floating type foundations shall also be acceptable providing the foundations are designed to adequately support the tank, contents and pumping equipment. Crushed rock of adequate depth would be acceptable.

7.4.2. Horizontal aboveground containers shall be mounted on foundations in such a manner as to permit expansion and contraction. Every container shall be supported so as to prevent the concentration of excessive loads on the supporting portion of the shell. The bearing afforded by the saddles shall extend over at least one third of the circumference of the shell. Suitable means for preventing corrosion shall be provided on that portion of the container in contact with the foundations or saddles.

7.4.3. Containers buried underground shall be placed so that the top of the container is at least one foot below the surface of the ground. Should ground conditions make compliance with these requirements impracticable, precautions shall be taken to prevent physical damage to the container. It is not necessary to cover the portion of the container to which a manhole and other connections are affixed. When necessary to prevent floating, containers shall be securely anchored or weighted.

7.4.4. Underground containers shall be set on firm foundations (firm earth may be used) and surrounded with soft earth or sand well tamped in place. As a further means of resisting corrosion, the container, prior to being placed underground, shall be given a protective coating satisfactory to the Commissioner. Such protective coating shall be equivalent to hot dip galvanizing, or to two preliminary coatings of red lead followed by a heavy coating of coal tar or asphalt. The container thus coated shall be lowered into place in such a manner as to prevent abrasion or other damage to the coating.

7.4.5. Distance between aboveground and underground containers of over 1,200 gallons capacity shall be at least five feet

7.4.6. Secure anchorage or adequate pier height shall be provided against container flotation wherever sufficiently high flood water might occur.

7.5.1. Containers once installed underground shall not later be reinstalled aboveground or underground, unless they successfully withstand hydrostatic pressure retests at the pressure specified for the original hydrostatic test as required by the code under which the tank was constructed and show no evidence of serious corrosion.

7.5.2. Where containers are reinstalled underground the corrosion resistant coating shall be put in good condition; see 7.4.4. Where containers are reinstalled aboveground, safety relief devices or gauging devices shall comply with 2.7 and 7.3 respectively for aboveground containers.

7.6.1. Each container or group of containers shall be marked on at least two sides with the words "Anhydrous Ammonia" in sharply contrasting colors with letters not less than four inches high and displayed a National Fire Protection Association diamond for anhydrous ammonia in a location that is readily visible to emergency responders.

7.7.1. Valves and other appurtenances shall be protected against physical damage. Main container shut-off valves shall be kept closed and locked when the installation is unattended. If the facility is protected against tampering by fencing or other suitable means, valve locks are not required.

7.7.2. All connections to underground containers should be located within a substantial dome, housing or manhole fitted with a substantial removable cover. Appurtenances shall also be protected during the transit of containers intended for installation underground.

7.7.3. Storage containers need not be grounded.

7.8.1. A sign shall be displayed in a conspicuous place stating the name, address, and phone number of the nearest representative, agent, or owner of the storage system.