There’s some good technical detail about the shell testing & possible shell classification here:
This forum is growing and has some of the pro posters from the defunct pyrofan forum.
The drop testing is of packaged or unpackaged articles. It is part of the series UN series 4 tests to determine suitability for transportation. Here is a link to the UN document that defines these tests.
The series 4 tests are yes/no result tests to determine if an explosive (firework) is safe to transport without the danger of accidental ignition from dropping or heat.
The drop test does not determine classification (EG. 1.4G, 1.3G or 1.1G)
The classification of fireworks to 1.1G, 1.2G, 1.3G, 1.4G is done using the series 6 tests. Series 6 tests are done on packaged articles.
I have had UN series 6 testing done on a number of products that I import into Canada. These products were classified using the UN Default Fireworks Classification Table as 1.1G and upon testing 1.3G classification was the result. I can say from my experience that it is very possible for a 6" shell to test as 1.1G if it had a substantial flash powder burst charge. I am also almost completely certain that a 72/1 box of 3" salutes with 1 color shell in it as is commonly sold in the USA would be 1.1G or 1.2G as long the salute has good quality flash powder in it as most salutes do. Also if the manufacturer cheaped out and used chlorate instead of perchlorate in the salute it is pretty much a certainty that the chlorate salutes would be 1.1G due to the much higher sensitivity of Chlorate compositions. Chlorate is cheaper than perchlorate so the profit motive is there
It is possible to package 3" salutes as 1.3G. This is how salutes are imported into Canada. Unfortunately this requires separation and packing in the box such that 1.3G packaged salutes are 18/1 in a box that is a bit larger than a 72/1 3" shell box. Due to the higher shipping and packaging cost it makes a 3" salute quite a bit more expensive.
If you think about it paying the extra expense and having 1.3G salutes might be a better solution that having a big pile of 3" salutes packed 72/1 accidentally ignite and cause a major accident causing injury and death. You know that is likely to cause regulatory action that would not be good for the fireworks industry. I would say to those guys that have a big pile of 72/1 3" salutes a good safety measure would be to put them in smaller piles in the magazine with other 1.3G or 1.4G products in between them. The nature of a 1.1G explosion is everything goes in one event because the shock of the explosion initiates all of the 1.1G material at once. At least if the salutes were in smaller piles separated by non 1.1G material each 1.1G explosion would be smaller.
I posted the info below recently on a Canadian forum so I thought I would repost it here. I hope this helps keep the 6" shells coming into the USA without extra packaging and the extra shipping expense that come with it.
I just had several hundred cases of 6" shells go through the first step of clearing the new system for inspecting/testing 6" shells. The testing lab selected 4 shells. 2 were Vortex Thunder and Silver Tail to Reports. Both are shell of shells with salutes inside. The other 2 were color shells. All of these shells have substantially less flash powder than the 25% where the UN Default Classification Table rules them as 1.1G. The lab declared over 25% flash powder which is incorrect. We took it up with the manager of the lab by presenting the technical information and the UN6B tests and showing how the lab had calculated the flash powder content incorrectly. The Manager agreed and passed the shells for shipment.
These shells are packaged in the usual boxes 9/1 and 10/1 with no additional cardboard or other packing.
Now the containers will go to Customs where they may be tested again so I will post the result of that when it happens.
It seems that the Chinese are applying the 25% flash powder content rule from the UN Default Fireworks Classification Table. Canada has applied the 25% flash powder rule since 2005. There are some problems with the testing in China. Hopefully the end result will be we can still get 6" shells and the shells that really are 1.1G are classified properly. It would not be good for the industry if one day a container of 1.1G 6" shells blows up at someones storage at 1.3G distances and kills or injures someone. No one wants people to get hurt or killed and the regulatory response to such an incident would likely not be good for the industry.