Subchapter 7. General Industry Safety Orders
Group 18. Explosive Materials
Article 114. Storage of Explosives

§5252. Quantity and Distances Table for the Storage of Explosives.

(a) The quantity of explosive materials that may be kept or stored in any magazine shall conform to Table EX-1, Table of Distances, which sets forth the minimum distance that a magazine may be located from the nearest inhabited building or other magazine.

(b) The quantity and distance table is not applicable to any magazine if the nearest inhabited building is effectually screened from the magazine by a natural barrier, which:

(1) Is 40 feet or more in height at any point, above a straight line drawn from the top of any sidewall of the magazine to any part of the inhabited building; and

(2) Has a natural thickness of not less than 200 feet at the point where it is intersected by the straight line.

(c) All types of blasting caps in strength through No. 8 shall be rated at 1 1/2 pounds of explosives per 1,000 caps. For strengths higher than No. 8 cap, consult the manufacturer.

(d) For quantity and distance purposes detonating cord up to 60 grains per foot shall be calculated as equivalent to 9 pounds of high explosives per 1,000 feet. Heavier detonating cord shall be rated proportion- ately.

(e) 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 shall 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 cap magazines shall govern in regard to the spacing of said cap 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 side of any magazine of the group, and must comply with the minimum of distances specified from other magazines and inhabited buildings.

TABLE EX-1

AMERICAN TABLE OF DISTANCES FOR STORAGE OF EXPLOSIVES MATERIALS As Revised and Approved by the Institute of Makers of Explosives - June 1991

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TABLE EX-2

Table of Separation Distances of Ammonium Nitrate and Blasting Agents from Explosives or Blasting Agents (1)

Donor Weight		Minimum Separation Distance
		of Acceptor when Barricaded (ft.)
				Minimum Thickness of
Pounds	Pounds	Ammonium		Artificial Barricades
Over	Not Over	Nitrate	Blasting Agent	(in.)
	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

NOTES:

(1) 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 distances of explosives or blasting agents, one-half the mass of the ammonium nitrate should be included in the mass of the donor.

(2) 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 Fertilizer Institute, and ammonium nitrate failing to pass said test shall be stored at separation distances determined by competent persons.

TABLE EX-3 Types of Storage Facilities

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As a result of tests with electric blasting caps, it has been determined that these blasting caps are not subject to sympathetic detonation. Therefore, a Type 4 storage facility meets the necessary requirements for storage of blasting caps that do not mass detonate.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 12006, Health and Safety Code.

HISTORY

1. Repealer and new section filed 10-17-75; effective thirtieth day thereafter (Register 75, No. 42).

2. Amendments filed 7-16-76; effective thirtieth day thereafter (Register 76, No. 29).

3. Amendment filed 9-18-80; effective thirtieth day thereafter (Register 80, No. 38).

4. Amendment of section heading, section and Note, including transfer of section 1938, App B, Plate B-14, table 1to replace former Table EX-1; transfer of section 5253 Table EX-2 to new section 5252 Table EX-2; and transfer of section 1938, App B, Plate B-14ato new Table EX-3, filed 7-11-2003; operative 8-10-2003 (Register 2003, No. 28).