29 C.F.R. § 1910.109
Current through September 30, 2024
Note 1: Classification of explosives is described by the U.S. Department of Transportation as follows (see 49 CFR chapter I):
Table H-21-American Table of Distances for Storage of Explosives1-5
[As revised and approved by the Institute of Makers of Explosives, June 5, 1964]
| Explosives | Distances in feet when storage is barricaded: Separation of magazines | |
| Pounds over | Pounds not over | |
| 2 | 5 | 6 |
| 5 | 10 | 8 |
| 10 | 20 | 10 |
| 20 | 30 | 11 |
| 30 | 40 | 12 |
| 40 | 50 | 14 |
| 50 | 75 | 15 |
| 75 | 100 | 16 |
| 100 | 125 | 18 |
| 125 | 150 | 19 |
| 150 | 200 | 21 |
| 200 | 250 | 23 |
| 250 | 300 | 24 |
| 300 | 400 | 27 |
| 400 | 500 | 29 |
| 500 | 600 | 31 |
| 600 | 700 | 32 |
| 700 | 800 | 33 |
| 800 | 900 | 35 |
| 900 | 1,000 | 36 |
| 1,000 | 1,200 | 39 |
| 1,200 | 1,400 | 41 |
| 1,400 | 1,600 | 43 |
| 1,600 | 1,800 | 44 |
| 1,800 | 2,000 | 45 |
| 2,000 | 2,500 | 49 |
| 2,500 | 3,000 | 52 |
| 3,000 | 4,000 | 58 |
| 4,000 | 5,000 | 61 |
| 5,000 | 6,000 | 65 |
| 6,000 | 7,000 | 68 |
| 7,000 | 8,000 | 72 |
| 8,000 | 9,000 | 75 |
| 9,000 | 10,000 | 78 |
| 10,000 | 12,000 | 82 |
| 12,000 | 14,000 | 87 |
| 14,000 | 16,000 | 90 |
| 16,000 | 18,000 | 94 |
| 18,000 | 20,000 | 98 |
| 20,000 | 25,000 | 105 |
| 25,000 | 30,000 | 112 |
| 30,000 | 35,000 | 119 |
| 35,000 | 40,000 | 124 |
| 40,000 | 45,000 | 129 |
| 45,000 | 50,000 | 135 |
| 50,000 | 55,000 | 140 |
| 55,000 | 60,000 | 145 |
| 60,000 | 65,000 | 150 |
| 65,000 | 70,000 | 155 |
| 70,000 | 75,000 | 160 |
| 75,000 | 80,000 | 165 |
| 80,000 | 85,000 | 170 |
| 85,000 | 90,000 | 175 |
| 90,000 | 95,000 | 180 |
| 95,000 | 100,000 | 185 |
| 100,000 | 110,000 | 195 |
| 110,000 | 120,000 | 205 |
| 120,000 | 130,000 | 215 |
| 130,000 | 140,000 | 225 |
| 140,000 | 150,000 | 235 |
| 150,000 | 160,000 | 245 |
| 160,000 | 170,000 | 255 |
| 170,000 | 180,000 | 265 |
| 180,000 | 190,000 | 275 |
| 190,000 | 200,000 | 285 |
| 200,000 | 210,000 | 295 |
| 210,000 | 230,000 | 315 |
| 230,000 | 250,000 | 335 |
| 250,000 | 275,000 | 360 |
| 275,000 | 300,000 | 385 |
1 "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.
2 "Artificial barricade" means an artificial mound or revetted wall of earth of a minimum thickness of three feet.
3 "Barricaded" means that a building containing explosives is effectually screened from a magazine, building, railway, or highway, either by a natural barricade, or by an artificial barricade of such height that a straight line from the top of any sidewall of the building containing explosives to the eave line of any magazine, or building, or to a point 12 feet above the center of a railway or highway, will pass through such intervening natural or artificial barricade.
4 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 explosives contained in cap magazines shall govern in regard to the spacing of said cap magazines from magazines containing other explosives. 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 explosives 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.
5 This table applies only to the permanent storage of commercial explosives. 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.
| Commodity | Type of marking or placard |
| Explosives, Class A, any quantity or a combination of Class A and Class B explosives | Explosives A (Red letters on white background). |
| Explosives, Class B, and quantity | Explosives B (Red letters on white background). |
| Oxidizing material (blasting agents, ammonium nitrate, etc.), 1,000 pounds or more gross weight | Oxidizers (Yellow letters on black background). |
Table H-22-Table of Recommended Separation Distances of Ammonium Nitrate and Blasting Agents From Explosives or Blasting Agents1-6
| Donor weight | Minimum separation distance of receptor when barricaded2 (ft.) | Minimum thickness of artificial barricades5 (in.) | ||
| Pounds over | Pounds not over | Ammonium nitrate3 | Blasting agent4 | |
| 100 | 3 | 11 | 12 | |
| 100 | 300 | 4 | 14 | 12 |
| 300 | 600 | 5 | 18 | 12 |
| 600 | 1,000 | 6 | 22 | 12 |
| 1,000 | 1,600 | 7 | 25 | 12 |
| 1,600 | 2,000 | 8 | 29 | 12 |
| 2,000 | 3,000 | 9 | 32 | 15 |
| 3,000 | 4,000 | 10 | 36 | 15 |
| 4,000 | 6,000 | 11 | 40 | 15 |
| 6,000 | 8,000 | 12 | 43 | 20 |
| 8,000 | 10,000 | 13 | 47 | 20 |
| 10,000 | 12,000 | 14 | 50 | 20 |
| 12,000 | 16,000 | 15 | 54 | 25 |
| 16,000 | 20,000 | 16 | 58 | 25 |
| 20,000 | 25,000 | 18 | 65 | 25 |
| 25,000 | 30,000 | 19 | 68 | 30 |
| 30,000 | 35,000 | 20 | 72 | 30 |
| 35,000 | 40,000 | 21 | 76 | 30 |
| 40,000 | 45,000 | 22 | 79 | 35 |
| 45,000 | 50,000 | 23 | 83 | 35 |
| 50,000 | 55,000 | 24 | 86 | 35 |
| 55,000 | 60,000 | 25 | 90 | 35 |
| 60,000 | 70,000 | 26 | 94 | 40 |
| 70,000 | 80,000 | 28 | 101 | 40 |
| 80,000 | 90,000 | 30 | 108 | 40 |
| 90,000 | 100,000 | 32 | 115 | 40 |
| 100,000 | 120,000 | 34 | 122 | 50 |
| 120,000 | 140,000 | 37 | 133 | 50 |
| 140,000 | 160,000 | 40 | 144 | 50 |
| 160,000 | 180,000 | 44 | 158 | 50 |
| 180,000 | 200,000 | 48 | 173 | 50 |
| 200,000 | 220,000 | 52 | 187 | 60 |
| 220,000 | 250,000 | 56 | 202 | 60 |
| 250,000 | 275,000 | 60 | 216 | 60 |
| 275,000 | 300,000 | 64 | 230 | 60 |
1 These distances apply to the separation of stores only. Table H-21 shall be used in determining separation distances from inhabited buildings, passenger railways, and public highways.
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 container, and the like which may enclose the "donor". Where storage is in bullet-resistant magazines recommended for explosives or where the storage is protected by a bullet-resistant wall, distances, and barricade thicknesses in excess of those prescribed in Table H-21 are not required.
3 The distances in the table apply to ammonium nitrate that passes the insensitivity test prescribed in the definition of ammonium nitrate fertilizer promulgated by the National Plant Food Institute*; and ammonium nitrate failing to pass said test shall be stored at separation distances determined by competent persons. (*Definition and Test Procedures for Ammonium Nitrate Fertilizer, National Plant Food Institute, November 1964.)
4 These distances apply to nitro-carbo-nitrates and blasting agents which pass the insensitivity test prescribed in the U.S. Department of Transportation (DOT) regulations.
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.
6 When the ammonium nitrate must be counted in determining the distances to be maintained from inhabited buildings, passenger railways and public highways, it may be counted at one-half its actual weight because its blast effect is lower.
NOTE 7: Guide to use of table of recommended separation distances of ammonium nitrate and blasting agents from explosives or blasting agents.
(a) Sketch location of all potential donor and acceptor materials together with the maximum mass of material to be allowed in that vicinity. (Potential donors are high explosives, blasting agents, and combination of masses of detonating materials. Potential acceptors are high explosives, blasting agents, and ammonium nitrate.)
(b) Consider separately each donor mass in combination with each acceptor mass. If the masses are closer than table allowance (distances measured between nearest edges), the combination of masses becomes a new potential donor of weight equal to the total mass. When individual masses are considered as donors, distances to potential acceptors shall be measured between edges. When combined masses within propagating distance of each other are considered as a donor, the appropriate distance to the edge of potential acceptors shall be computed as a weighted distance from the combined masses.
Calculation of weighted distance from combined masses:
Let M2, M3 . . . Mn be donor masses to be combined.
M1 is a potential acceptor mass.
D12 is distance from M1 to M2 (edge to edge).
D13 is distance from M1 to M3 (edge to edge), etc.
To find weighted distance [D1(2,3 . . .n)] from combined masses to M1, add the products of the individual masses and distances and divide the total by the sum of the masses thus:
D1(2,3 . . .n)=M2 * D12 + M3 * D12 . . . + Mn * D12M2 + M3 . . . + Mn
Propagation is possible if either an individual donor mass is less than the tabulated distance from an acceptor or a combined mass is less than the weighted distance from an acceptor.
(c) In determining the distances separating highways, railroads, and inhabited buildings from potential explosions (as prescribed in Table H-21), the sum of all masses which may propagate (i.e., lie at distances less than prescribed in the Table) from either individual or combined donor masses are included. However, when the ammonium nitrate must be included, only 50 percent of its weight shall be used because of its reduced blast effects. In applying Table H-21 to distances from highways, railroads, and inhabited buildings, distances are measured from the nearest edge of potentially explodable material as prescribed in Table H-21, Note 5.
(d) When all or part of a potential acceptor comprises Explosives Class A as defined in DOT regulations, storage in bullet-resistant magazines is required. Safe distances to stores in bullet-resistant magazines may be obtained from the intermagazine distances prescribed in Table H-21.
(e) Barricades must not have line-of-sight openings between potential donors and acceptors which permit blast or missiles to move directly between masses.
(f) Good housekeeping practices shall be maintained around any bin containing ammonium nitrate or blasting agent. This includes keeping weeds and other combustible materials cleared within 25 feet of such bin. Accumulation of spilled product on the ground shall be prevented.
29 C.F.R. §1910.109