PDFWAC 296-52-69115

Table H-22—Separation distances of ammonium nitrate and blasting agents from explosives or blasting agents.

Table H-22
table of separation distances of ammonium nitrate and blasting agents
from explosives or blasting agents1
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
Note 1:
These distances apply to the separation of storage. Table H-20 must be used in determining separation distances from inhabited buildings, passenger railways, and public highways.
Note 2:
When the ammonium nitrate and/or blasting agent is not barricaded, the distances shown in the table must 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." When ammonium nitrate is stored in a bullet resistant magazine it is recommended explosives or where the storage is protected by a bullet resistant wall, distances, and barricade thickness in excess of those prescribed in Table H-20 are not required.
Note 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 Fertilizer Institute, and ammonium nitrate failing to pass a test must be stored at separation distances determined by competent persons. (Definition and Test Procedures for Ammonium Nitrate Fertilizer, the Fertilizer Institute, formerly the National Plant Food Institute, November 1964.)
Note 4:
These distances apply to nitro-carbo-nitrates and blasting agents, which pass the insensitivity test prescribed in the U.S. DOT regulations.
Note 5:
Acceptable barricades include either natural or artificial barricades as defined in WAC 296-52-60130, Definitions.
Note 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 the location of all potential donors and acceptor materials together with the maximum amount of material to be allowed in the area. (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 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 must 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 must be computed as a weighted distance from the combined masses:
 
(i) 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:
D1(2,3…n) = M2 x D12 + M3xD13 + Mn x Din
M2 + 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) When determining the distances separating highways, railroads, and inhabited buildings from potential explosions (as prescribed in Table H-20), 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, the ammonium nitrate must be included, only 50 percent of its weight must be used because of its reduced blast effects. In applying Table H-21, distances from highways, railroads, and inhabited buildings, distances are measured from the nearest edge of potentially explodable material.
 
(d) When all or part of a potential acceptor comprises explosives Class A as defined in U.S. DOT regulations, storage in bullet resistant magazines is required. Safe distances to stores in bullet resistant magazines may be obtained from the intermagazine distances described in Table H-21.
 
(e) Barricades cannot have line of sight openings between potential donors and acceptors, which permit blast or missiles to move directly between masses.
 
(f) Good housekeeping practices must be maintained around any bin containing ammonium nitrate or blasting agent. This includes keeping weeds and other combustible materials cleared within twenty-five feet of the bin. Accumulation of spilled product on the ground must be prevented.
[Statutory Authority: RCW 49.17.010, [49.17].040, and [49.17].050. WSR 02-03-125, § 296-52-69115, filed 1/23/02, effective 3/1/02.]