Post by bigtop on Jan 4, 2018 12:15:04 GMT -5
The incident in Terrigal Beach Australia (link below) should be a reminder that we need to test our mortar racks/setups with shells in the mortars adjacent to the mortar that we burst the shell in. In the article it shows a mortar setup by the same company with no space between the mortars. When one shell bursts with no space between the mortars it will initiate the shells adjacent to it by the shock of the explosion causing a chain reaction from loaded mortar to loaded mortar.
www.smh.com.au/nsw/a-freak-thing-exploding-cannister-blamed-for-terrigal-beach-fireworks-mishap-20180101-h0c6de.html
It was fortunate that no one was hurt in the incident and it appears that there was some structure on the barge that stopped the shells from shooting horizontally towards the crowd. The two shooters on the barge were obviously put in great danger by the chain reaction of bursting shells but managed to get off the barge without injury. That is not always the case. As demonstrated in the Simi Valley accident there was a chain reaction with mortars falling over firing towards the crowd. Mortar and rack parts were also projected towards the crowd. The link is below.
www.youtube.com/watch?v=awRBqJDL3h0
We need to work to avoid these kinds of incidents. The indestructible rack standard in the Display Fireworks Manual has helped avoid incidents like this in Canada. The last thing we want is to hurt people and damage property at fireworks displays. Not only is it wrong morally but it causes high insurance costs and is likely to cause more regulatory burden to producing display fireworks shows.
So if you build your own racks you can't know what will happen until you test your racks with shells in the mortars adjacent to the one that you burst the shell in (do it safely and in compliance with the laws and regulations). From experience I have found that you never really know what is going to happen until you blow it up and see what happens.
Just to give some idea of how it works I will give two examples. In the USA I have seen a test where one 1.75" consumer fireworks shell in a mortar initiated another 1.75" consumer shell in an adjacent mortar with no space between them. In testing of my own racks I have seen a 3" salute not initiate another 3" salute with a space of 3.5" between the mortars.
For those that don't know although it is a rare malfunction eventually if you fire enough shells one is going to burst in the mortar. All it takes is a small pinhole in the seal around the time fuse of the shell and the fire from the lift charge will shoot right into the shell bursting it in the mortar. Also far more common is the the possibility of human error of a shell being loaded upside down.
www.smh.com.au/nsw/a-freak-thing-exploding-cannister-blamed-for-terrigal-beach-fireworks-mishap-20180101-h0c6de.html
It was fortunate that no one was hurt in the incident and it appears that there was some structure on the barge that stopped the shells from shooting horizontally towards the crowd. The two shooters on the barge were obviously put in great danger by the chain reaction of bursting shells but managed to get off the barge without injury. That is not always the case. As demonstrated in the Simi Valley accident there was a chain reaction with mortars falling over firing towards the crowd. Mortar and rack parts were also projected towards the crowd. The link is below.
www.youtube.com/watch?v=awRBqJDL3h0
We need to work to avoid these kinds of incidents. The indestructible rack standard in the Display Fireworks Manual has helped avoid incidents like this in Canada. The last thing we want is to hurt people and damage property at fireworks displays. Not only is it wrong morally but it causes high insurance costs and is likely to cause more regulatory burden to producing display fireworks shows.
So if you build your own racks you can't know what will happen until you test your racks with shells in the mortars adjacent to the one that you burst the shell in (do it safely and in compliance with the laws and regulations). From experience I have found that you never really know what is going to happen until you blow it up and see what happens.
Just to give some idea of how it works I will give two examples. In the USA I have seen a test where one 1.75" consumer fireworks shell in a mortar initiated another 1.75" consumer shell in an adjacent mortar with no space between them. In testing of my own racks I have seen a 3" salute not initiate another 3" salute with a space of 3.5" between the mortars.
For those that don't know although it is a rare malfunction eventually if you fire enough shells one is going to burst in the mortar. All it takes is a small pinhole in the seal around the time fuse of the shell and the fire from the lift charge will shoot right into the shell bursting it in the mortar. Also far more common is the the possibility of human error of a shell being loaded upside down.