24 replies to this topic

[David]

I was under the assumption that for a (non-pyromeshed) firework to be class as 1.4G it needed to have less than 5% flashpower per tube.

Is that correct?

The key thing here is "per tube."

Edited by David, 27 July 2009 - 10:35 PM.

[Spyrotechnics]

something now led you to believe otherwise?

[David]

something now led you to believe otherwise?

No.

I'm just thinking, what about single tube fireworks- such as multi-shot bombette candles? A 5% of flash "per tube" rule is effectivly 5% flash per firework in these cases- So, a firework such as this could have a flash finale bang, and still remain in 1.4G limits.

Or am I missing something?

Edited by David, 27 July 2009 - 10:42 PM.

[Rick]

A battery of roman candles or shot tubes is classified as to the candle/tube that presents the greatest hazard.
ie each tube is looked at individually so the <5% flash cannot be applied to the firework as a whole.

[David]

A battery of roman candles or shot tubes is classified as to the candle/tube that presents the greatest hazard.
ie each tube is looked at individually so the <5% flash cannot be applied to the firework as a whole.

Yeah, that much is clear- however, what about multi-shot fireworks fired from a single tube- multi shot roman candles?

[Spyrotechnics]

I would assume the same principle applies, item is classified by the "shot" that represents the greatest hazard.

[Rick]

Sorry David, mis-read your post, thought you were talking about single shot tubes forming batteries.
In regard to Roman Candles (multishot) it is each pyrotechnic unit that is looked at.
Pyrotechnic unit <=25g with <=5% flash composition

[chimp]

Daft question, and probably in the wrong thread, but given that the maximum composition weight for each pyrotechnic unit is now 25g, does this mean that 30mm bore cakes are no longer to be assumed to be more 'pokey' than say 20mm or 25mm products. To put it another way, what is the typical unit weight in a 20mm tube - if it can be 25g then does it follow that 'max' bore size is now a misnomer in terms of judging the 'meatiness' of a cake, as a smaller bore cake is likely to be just as punchy?

[David]

Daft question, and probably in the wrong thread, but given that the maximum composition weight for each pyrotechnic unit is now 25g, does this mean that 30mm bore cakes are no longer to be assumed to be more 'pokey' than say 20mm or 25mm products. To put it another way, what is the typical unit weight in a 20mm tube - if it can be 25g then does it follow that 'max' bore size is now a misnomer in terms of judging the 'meatiness' of a cake, as a smaller bore cake is likely to be just as punchy?

It's an excellent point, and well made.

Anyone know the answer?


......

Also- does the maximum composition weight of 25g apply to 1.3G as well?

[chimp]

It would be interesting to get a manufacturer's clarification on this point......

[David]

It would be interesting to get a manufacturer's clarification on this point......

Yeah, I'll keep an eye out too on stuff I fire, to see if the 30mm bore stuff is producing the biggest effects.

[chimp]

Yeah, I'll keep an eye out too on stuff I fire, to see if the 30mm bore stuff is producing the biggest effects.

Well, some of the new spec 30mm cakes I've tested have certainly not outshone other, smaller bore units............ Maybe the sales pitch will change from 'maximum legal bore size' to maximum 'shot weight'. If it does, then hopefully we may see smaller cakes which cost less to manufacture and therefore carry a lower rrp.......

[David]

Well, some of the new spec 30mm cakes I've tested have certainly not outshone other, smaller bore units............ Maybe the sales pitch will change from 'maximum legal bore size' to maximum 'shot weight'. If it does, then hopefully we may see smaller cakes which cost less to manufacture and therefore carry a lower rrp.......

That said, if 20mm or 25mm bore is enough for the maximum composition limits, what exactly is taking up the space in the tubes that are 30mm bore size?

Does that make sense?

IE presuming that 30mm bore size tubes ARE firing out bombettes that are wider (as per the tube size), then what is being used to make them that size, if not composition?

This suggests it is 28mm bore size, and less than 24g per bombette (sort of.) EIG upload I'm not exactly sure what these slides are.

Edited by David, 02 August 2009 - 01:07 AM.

[chimp]

I was 'informed' a couple of days ago from an importer that the nominal 25g weight can be quite typical for 20~25 bore tubes...

Whether or not this is wholely accurate I do not know, but if it is (to go back to the original point) what is the 'benefit' of larger tubes?

I wonder how many know but choose to keep shtum..

[David]

I was 'informed' a couple of days ago from an importer that the nominal 25g weight can be quite typical for 20~25 bore tubes...

Whether or not this is wholely accurate I do not know, but if it is (to go back to the original point) what is the 'benefit' of larger tubes?

I wonder how many know but choose to keep shtum..

Apparantly one of the benefits of a larger tube is that it allows for the bombette/shot to be less elongated, which makes for a more symetrical burst.

IE a 25g shot could indeed be fired from a 20mm tube, but the burst would be affected (basically, it would look a bit wonky) by the shape of the shot/bombette.

Edited by David, 09 August 2009 - 03:51 PM.