Control of Pyrotechnic Burn Rate

B. J. and K. L. Kosanke

ABSTRACT: There may be many times when a firework manufacturer will want to adjust the burn rate of pyrotechnic compositions. Sometimes this may be for matters of esthetics and other times for safety. For example, all of the following are unacceptable:

• Strobe stars that flash with so low a frequency that they fall to the ground still burning.

• Color stars that burn so rapidly that they occasionally explode when a shell flowerpots.

• Rockets that fail to lift-off because their thrust is too low.

• Rockets that explode upon firing because internal pressures exceed the casing strength.

• Salutes that burn like fountains instead of  exploding with violence.

• Flash powder that explodes when unconfined,  even in small quantity.

In each case, taking action to adjust burn rate should solve the problem. Depending somewhat on how they are counted, there are at least 15 factors that control pyrotechnic burn rate. A  anufacturer that understands how these factors act to affect burn rate may better anticipate when product performance difficulties will occur. Also, such a manufacturer will be better prepared to modify product formulations to correct any problems that do occur. Each of the burn rate control factors act by affecting one or more of the following: activation energy, heat of reaction, and efficiency of energy feedback. In this paper, the 15 factors are presented, explained and examples given.

Ref: Selected Pyrotechnic Publication of K.L. and B.J Kosanke, Part 3, (1993-1994), pp 62-75

© Journal of Pyrotechnics and CarnDu Ltd

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