Ammonium Nitrate

CAS RN: 6484-52-2

Storage Conditions

Closed containers may rupture violently when heated.
Keep well closed.
Separate from acids, alkalies, reducing agents, combustible materials. Store in a cool, dry, well ventilated location.
Fire protection: Ammonium nitrate storage areas should be equipped with an automatic sprinkler system, or have an automatic fire detection and alarm system if the areas are not continuously occupied. This is especially important when the facility in question is close to the public surrounding the facility. Facilities should NOT store more than 2500 tons of bagged ammonium nitrate without an automatic sprinkler system. An automatic sprinkler system, if installed, should be provided in accordance with NFPA 13, Standard for the Installation of Sprinkler Systems. Suitable fire control devices such as hoses and appropriate portable fire extinguishers (ammonium nitrate is an oxidizer and not all fire extinguishers are appropriate) shall be provided throughout the warehouse and loading areas. Water supplies and fire hydrants should be available. Store ammonium nitrate fertilizer in separate buildings or separated by approved fire walls from organic, combustible or reactive materials, such as grains, wood or other organic materials, urea and urea compounds, flammable liquids or gases, corrosive acids, chlorates, chromates nitrites, permanganates or finely divided metals or sulfur. Ammonium nitrate fertilizer should NOT be stored in the same building with explosives or blasting agents unless conditions in ATF's Table of Separation Distances of Ammonium Nitrate and Blasting Agents from Explosives and Blasting Agents, 27 CFR 555.220, are met. Prohibit smoking in ammonium nitrate storage areas.
Storage in bulk: Bins for storing bulk ammonium nitrate should be kept clean and free of materials, which could contaminate the material. Bins should not be constructed of galvanized iron, copper, lead or zinc unless suitably protected. Aluminum or wooden bins should be protected against impregnation by ammonium nitrate. Piles or bins must be adequately sized, arranged and moved periodically to minimize caking. Height or depth of piles shall be limited by pressure-setting tendency of the product, but in no case should pile be higher than 36 inches below roof or supporting beams. Do NOT use dynamite, explosives or blasting agents to break up or loosen caked ammonium nitrate. Protect piles of ammonium nitrate from absorbing moisture from humid air by covering them with water-impermeable sheeting or using air conditioning. Do not store AN with organic chemicals, acids, or other corrosive materials, materials that may require blasting during processing or handling, compressed flammable gases, flammable and combustible materials or other contaminating substances. Ammonium nitrate stores should be separated from incompatible substances by using separate buildings or 1 - hour fire resistant walls, or a minimum separation distance of 30 feet.
Storage in bags, drums or other containers: Piles of bags, drums and other containers should be no closer than 36 inches below the roof or supporting beams. Bags should be stored no less than 30 inches from walls or partitions. Piles of bags, drums, and other containers should not exceed a height of 20 feet, width of 20 feet, and length of 50 feet, unless the building is of noncombustible construction or protected by automatic sprinklers. Maintain aisles of at least 3 feet width between piles.
Building design: Store only in one-story buildings and buildings with no basements, unless the basement is open on one side. Use fire resistant walls within 50 feet of combustible building or materials. Flooring in storage and handling areas should be constructed of noncombustible material or protected from impregnation by ammonium nitrate. Avoid installing, or remove or close off any open drains, traps, tunnels, pits or pockets into which molten AN can flow and be confined in the event of fire. Buildings should be kept dry and free of water seepage through roofs, walls and floors. Have adequate ventilation or be constructed to self-ventilate in the event of a fire to avoid pressurization. Do not place ammonium nitrate into storage when the temperature of the product exceeds 130 deg F (54.4 deg C).
Persons engaged in the handling, management or emergency planning for ammonium nitrate must be aware of the hazards of ammonium nitrate and ensure that the conditions that may lead to an explosion are not present. Measures that facilities should take to ensure the safe storage, use and handling of ammonium nitrate include: 1. Avoid heating ammonium nitrate in a confined space. (Processes involving ammonium nitrate should be designed to avoid this possibility. Avoid localized heating of ammonium nitrate, potentially leading to development of high temperature areas (e.g., ammonium nitrate fertilizer should not be stored near sources of heat such as steam pipes, radiators, hot ducts, light bulbs etc.)). 2. Ensure that ammonium nitrate is not exposed to strong shock waves from explosives. 3. Avoid contamination of ammonium nitrate with combustible materials or organic substances such as packing materials, dust, seed, oils, and waxes. (If possible, do not co-locate ammonium nitrate, especially bulk ammonium nitrate in bins, with dust-producing organics such as grains or seeds.) 4. Avoid contamination of ammonium nitrate with inorganic materials that may contribute to its sensitivity to explosion, including chlorides and some metals, such as aluminum powder, chromium, copper, cobalt, and nickel. (Pay attention to the materials used to build storage areas and cribs. Wood and aluminum or other metals must be specially treated to prevent impregnation if they are going to be in contact with ammonium nitrate. Metal materials can be treated with epoxy tar or chlorinated rubbers to prevent corrosion of the metal and contamination of the ammonium nitrate.) 5. Maintain the pH of ammonium nitrate solutions within the safe operating range of the process. In particular, avoid low pH (acidic) conditions. (If possible, do not co-locate acids in an ammonium nitrate storage area.) 6 Keep molten or solid ammonium nitrate out of confined spaces, especially sewers or drains where it can react with organic materials there.
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