All firework applications submitted for approval to the U.S. Department of Transportation will need to describe the particle (micron) size for any metal composition used in a device. The following chart provides the conversion for standard entries from mesh to microns.
Example : Titanium is required to be larger than 100 mesh in a 1.4G device – the equivalent conversion would be 149 microns.
US MESH
|
INCHES
|
MICRONS
|
MILLIMETERS
|
50
|
0.0117
|
297
|
0.297
|
60
|
0.0098
|
250
|
0.250
|
70
|
0.0083
|
210
|
0.210
|
80
|
0.0070
|
177
|
0.177
|
100
|
0.0059
|
149
|
0.149
|
120
|
0.0049
|
125
|
0.125
|
140
|
0.0041
|
105
|
0.105
|
170
|
0.0035
|
88
|
0.088
|
200
|
0.0029
|
74
|
0.074
|
230
|
0.0024
|
63
|
0.063
|
270
|
0.0021
|
53
|
0.053
|
325
|
0.0017
|
44
|
0.044
|
400
|
0.0015
|
37
|
0.037
|
NOTE(s):
**** Titanium - particle size must be larger than 149 microns
**** Particle size must be provided for all metals in the Fireworks (EX) Approval Application