Magazine Locations & American Table of Distances
(A) Outdoor magazines in which high explosives are stored shall be located no closer to inhabited buildings, passenger railways, public highways or other magazines in which high explosives are stored than the minimum distances specified in the American Table of Distances for Storage of Explosive Materials in Table 4-5-1.
(B) Outdoor magazines in which low explosives are stored shall be located no closer to inhabited buildings, passenger railways, public highways or other magazines in which explosives are stored than the minimum distances specified in the American Table of Distances for Storage of Low Explosives in Table 4-5-2. The distances shown therein may not be reduced by the presence of barricades
(C) Outdoor magazines in which blasting agents are stored shall be located no closer to inhabited buildings, passenger railways or public highways than the minimum distances specified in the American Table of Distances for Storage of Explosive Materials in Table 4-5-1.
(D) Ammonium nitrate and magazines in which blasting agents are stored shall be located no closer to magazines in which high explosives or other blasting agents are stored than the minimum distances specified in the American Table of Distances for the Separation of Ammonium Nitrate and Blasting Agents in Table 4-5-3. However, the minimum distances for magazines in which explosives and blasting agents are stored from inhabited buildings, passenger railways or public highways may not be less than the distances specified in the American Table of Distances for Storage of Explosive Materials in Table 4-5-1.
Explanatory Notes Essential to the Application of the American Table of Distances for Storage of Explosive Materials
NOTE 1 “Explosive materials” means explosives, blasting agents and detonators.
NOTE 2 “Explosives” means any chemical compound, mixture, or device, the primary or common purpose of which is to function by explosion. For quantity and distance purposes, detonating cord of 50 grains per foot should be calculated as equivalent to 8 lbs. of high explosives per 1,000 feet. Heavier or lighter core loads should be rated proportionately.
NOTE 3 “Blasting agents” means any material or mixture, consisting of fuel and oxidizer, intended for blasting, not otherwise defined as an explosive provided that the finished product as mixed for use or shipment, cannot be detonated by means of a No.8 test blasting cap when unconfined.
NOTE 4 “Detonator” means any device containing any initiating or primary explosive that is used for initiating detonation. A detonator may not contain more than 10 grams of total explosives by weight, excluding ignition or delay charges. The term includes, but is not limited to, electric blasting caps of instantaneous and delay types, electronic detonators blasting caps for use with safety fuses, detonating cord delay connectors, and non-electric instantaneous and delay blasting caps which use detonating cord, shock tube, or any other replacement for electric leg wires. All types of detonators in strengths through No.8 cap should be rated at 1 1/2 lbs. of explosives per 1,000 caps. For strengths higher than No.8 cap consult the manufacturer.
NOTE 5 “Magazine” means any building, structure, or container, other than an explosives manufacturing building, approved for the storage of explosive materials.
NOTE 6 “Natural Barricade” means natural features of the ground such as hills, or timber of sufficient density that the surrounding exposures which require protection cannot be seen from the magazine when the trees are bare of leaves.
NOTE 7 “Artificial Barricade” means an artificial mound or wall of earth of a minimum thickness of three feet.
NOTE 8 “Barricaded” means the effective screening of a building containing explosive materials from the magazine or other building, railway, or highway by a natural or an artificial barrier. A straight line from the top of any sidewall of the building containing explosive materials to the eave line of any magazine or other building or to a point twelve feet above the center of a railway or highway shall pass through such barrier.
NOTE 9 “Inhabited Building” means a building regularly occupied in whole or part as a habitation for human beings, or any church, schoolhouse, railroad station, store, or other structure where people are accustomed to assemble, except any building or structure occupied in connection with the manufacture, transportation, storage or use of explosive materials.
NOTE 10 “Railway” means any steam, electric, or other railroad or railway which carries passengers for hire.
NOTE 11 “Highway” means any public street, public alley, or public road.
NOTE 12 When two or more storage magazines are located on the same property, each magazine must comply with the minimum distances specified from inhabited buildings, railways and highways, and, in addition, they should be separated from each other by not less than the distances shown for “Separation of Magazines,” except that the quantity of explosive materials contained in detonator magazines shall govern in regard to the spacing of said detonator magazines from magazines containing other explosive materials. If any two or more magazines are separated from each other by less than the specified “Separation of Magazines” distances, then such two or more magazines, as a group, must be considered as one magazine, and the total quantity of explosive materials stored in such group must be treated as if stored in a single magazine located on the site of any magazine of the group, and must comply with the minimum of distances specified from other magazines, inhabited buildings, railways, and highways.
NOTE 13 Storage in excess of 300,000 lbs. of explosive materials, in one magazine is generally not required for commercial enterprises.
NOTE 14 This Table applies only to the manufacture and permanent storage of commercial explosive materials. It is not applicable to transportation of explosives or any handling or temporary storage necessary or incident thereto. It is not intended to apply to bombs, projectiles, or other heavily encased explosives.
NOTE 15 When a manufacturing building on an explosive materials plant site is designed to contain explosive materials, such building shall be located from inhabited buildings, public highways and passenger railways in accordance with the American Table of Distances based on the maximum quantity of explosive materials permitted to be in the building at one time.
American Table of Distances
The American Table of Distances covers all commercial explosive materials, including, but not limited to, high explosives, blasting agents, detonators, initiating systems and explosives materials in process. The Table is not designed to be altered or adjusted to accommodate varying explosive characteristics such as blast effect, weight strength, density, bulk strength, detonation velocity, etc.
The American Table of Distances should not be used to determine safe distances for blasting work, the firing of explosive charges for testing or quality control work, or the open detonation of waste explosive materials. The American Table of Distances may be utilized as a guide for developing distances for the unconfined, open burning of waste explosive materials where the probability of transition from burning to high order detonation is improbable.
Notes to Table of Recommended Separation Distances of Ammonium Nitrate and Blasting Agents from Explosives or Blasting Agents
NOTE 1 Recommended separation distances to prevent explosion of ammonium nitrate and ammonium nitrate-based blasting agents by propagation from nearby stores of high explosives or blasting agents referred to in the Table as the “donor.” Ammonium nitrate, by itself, is not considered to be a donor when applying this Table. Ammonium nitrate, ammonium nitrate-fuel oil or combinations thereof are acceptors. If Stores of ammonium nitrate are located within the sympathetic detonation distance of explosives or blasting agents, one-half the mass of the ammonium nitrate should be included in the mass of the donor.
NOTE 2 When the ammonium nitrate and/or blasting agent is not barricaded, the distances shown in the Table shall be multiplied by six. These distances allow for the possibility of high velocity metal fragments from mixers, hoppers, truck bodies, sheet metal structures, metal containers, and the like which may enclose the “donor.” Where storage is in bullet- resistant magazines is recommended for explosives or where the storage is protected by a bullet-resistant wall, distances and barricade thicknesses in excess of those prescribed in the American Table of Distances are not required.
NOTE 3 The distances in the Table apply to ammonium nitrate and ammonium nitrate based materials that show “negative” (-) result in the UN Test Series 2 Gap Test and show “positive” (+) result in the UN Test Series 1 Gap Test. Ammonium nitrate and ammonium nitrate based materials that are DOT hazard Class 1 sensitive shall be stored at separation distances determined by the American Table of Distances.
NOTE 4 These distances apply to blasting agents which pass the insensitivity test prescribed in regulations of the U.S. Department of Transportation and the U.S. Department of the Treasury, Bureau of Alcohol, Tobacco and Firearms.
NOTE 5 Earth, or sand dikes, or enclosures filled with the prescribed minimum thickness of earth or sand are acceptable artificial barricades. Natural barricades, such as hills or timber of sufficient density that the surrounding exposures which require protection cannot be seen from the “donor” when the trees are bare of leaves, are also acceptable.
NOTE 6 For determining the distances to be maintained from inhabited buildings, passenger railways, and public highways, use the American Table of Distances for Storage of Explosives Materials on pages 58 and 59.
*For construction of bullet-resistant magazines see Bureau of Alcohol, Tobacco and Firearms, Department of the Treasury, Publication ATF P 5400.7 (9/00), ATF-Explosives Law and Regulations.
