Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-52 - Safety standards for possession, handling, and use of explosives › Part E - STORAGE OF EXPLOSIVE MATERIALS › QUANTITY AND DISTANCE TABLES › Section 296-52-69115 - Table H-22 - Separation distances of ammonium nitrate and blasting agents from explosives or blasting agents

Current through Register Vol. 24-14, July 15, 2024
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 .
						02-03-125, § 296-52-69115, filed 1/23/02, effective
						3/1/02.