Brisance of commercial salutes:

[RalphieJ]

This has been on my mind for years, but never thought to ask. There's a noticeable difference in the sounds of commercial salutes, what my local plant owners referred to brisance. Some go bang, like a large paper cracker, some go boom, with that delicious 'thud'. What creates the different sound, is it the mix, or is it container?

[Arclight]

It's probably a couple of factors:

1. Black powder vs flash, which has a bunch of different formulas.
2. Better containment of the explosion (ie. a heavier casing)
3. Critical diameter (not all explosives reach their full velocity in a given diameter of confinement). This is a principle from blasting rock that probably applies here.

[PyroJoeNEPA]

Flash formulae have different sounds---IE: TPA flash sounds completely different from 70/30 in the same container with the same weight of powder. Flash with sulfur sounds different than standard 70/30. And there are may, many many different formulae for types of flash.
Brisance is a term used more in the blasting field referring to RDX or C4 and it's explosive power===
Arclight, maybe you can comment on that.
Not a term I have come across in the pyrotechnics manufacturing field.

[Blaster]

And there's the Chlorate ~vs~ PerChlorate thing... ;)

[Arclight]

Flash formulae have different sounds---IE: TPA flash sounds completely different from 70/30 in the same container with the same weight of powder. Flash with sulfur sounds different than standard 70/30. And there are may, many many different formulae for types of flash.
Brisance is a term used more in the blasting field referring to RDX or C4 and it's explosive power===
Arclight, maybe you can comment on that.
Not a term I have come across in the pyrotechnics manufacturing field.

Right, Brisance is a term that describes "shattering power" but there is no standard measure of it. In general, higher brisance means that an explosive is more capable of cutting things like steel or other hard materials. Military users care about this. For rock blasting, you mostly care about VOD (velocity of detonation), and RE (relative effectiveness, usually measured compared to TNT or ANFO). If the RE of TNT is 1.00, C4 would be something like 1.30 and ANFO would be 0.8. It allows you to compare how much explosive is needed to do the same amount of "work" as a different one.

[wingman]

Right, Brisance is a term that describes "shattering power" but there is no standard measure of it. In general, higher brisance means that an explosive is more capable of cutting things like steel or other hard materials. Military users care about this. For rock blasting, you mostly care about VOD (velocity of detonation), and RE (relative effectiveness, usually measured compared to TNT or ANFO). If the RE of TNT is 1.00, C4 would be something like 1.30 and ANFO would be 0.8. It allows you to compare how much explosive is needed to do the same amount of "work" as a different one.

Arclight,

Thanks for your input on this! I've often referred to brisance as the overall pitch as well as concussiveness of the report in a salute/shell. Would a higher pitch indicate a higher VOD? In some countries like India which use nitrate-based report formulae, the pitch seems very, very low, very loud and the concussiveness is rather noticeable compared to standard perc-based formulae, where some seem to have a very sharp report but not quite as concussive.

Either way, I'm not sure why, but over the years I've grown to really admire the deep, cannon-like reports that nitrate-based mixes lend over the sharp, ear-piercing "high order-like" reports or breaks.

[Arclight]

I'm sure VOD. amount of gas produced and maybe peak pressure play into what an explosion sounds like. I can say that detcord (usually PETN based) has a very loud, higher-frequency sound that is kind of like a louder version of a high-powered rifle. Dynamite, on the other hand, has a feeling more like a big rock being dropped from a crane.