July 4th - Display Incident in Texas

[Fuse]

I was tracking this incident since I live in Texas. Plano, TX(pop. 280k) is a major suburb of Dallas, TX. It was reported that a 6" shell exploded in the tube and that scattered other tubes containing delay chains all around, including some fairly close to spectators. In the drone video, you can see multiple fires already burning in the grass even before the incident, must have been very dry, but after the incident, grass fires were widespread. I feel for the display crew, what a mess, but no injuries were reported.

Plano Fireworks Show Ends with Accidental Ground Explosions Near Viewers, Brush Fires

The rockets' red glare caused quite a scare during Plano's Fourth of July fireworks show. Some of the rockets in the city's annual fireworks display launched in private fields veered off course and landed very close to some of the spectators. Other fireworks exploded on the field, starting three...

www.dallasobserver.com

 

[Blaster]

Very Interesting video, the perspective from the air of all those Grass Fires, wasn't the ground crew aware? What it must have looked like to them I wonder?

So the shell in the center that went off on/close to the ground didn't seem like the cause of Everything though. I wonder if the grass fires got to some of the set-up first (and then of course So Many more would have started). I can't believe the Fire Marshal would have allowed them to shoot from such a vulnerable site with those conditions. In my neck-of-the-woods, they would have recognized the potential for all that dry grass to get involved

Because that's where I normally am, I really have to ponder on what it all would have looked like from the crews point-of-view...

 

[Fuse]

It's clear to me that the number of fires increased greatly after the tube explosion, you can see in the drone & crowd video delay chained shells exploding in the grass right after it. It's July in Texas, it's not unusual to have small grass fires and have pyro & fire dept. crews fight them during a display. What's unusual is the tube explosion and resulting low breaks that threaten spectators and light alot of fires at once.

 

[Torch]

That is an interesting video. Credit to the city for wanting to give everyone a good show for the 4th. Ironically, they advertised it as "pyrotechnics will be shot off at a higher altitude.... should allow them to be seen from farther away." Sounds like most of it went as planned.

All American 4th | Plano, TX

Seasonal flyer with Plano's 4th of July Fireworks display information (date, time, location)

www.plano.gov

Glad everyone is OK.

Wonder if the agreement with the farm was to let fields burn - it looks like a standout farm being surrounded by suburbia.

 

[DarkPyro]

Awesome video. Thanks for sharing. Glad no one was hurt.

 

[BigTopCanada]

I am also glad that no one was hurt. If the racks were compliant with NFPA 1123 4.5.7 through 4.6.11 the other tubes would not have been scattered causing several shells to explode on the ground. This kind of preventable accident should not be happening. One mortar exploding scattering other mortars causing shells to be propelled in random directions is a major cause of damage, injuries and high insurance premiums that make all fireworks more expensive. The guy that is shooting out of racks that fall over when a shell explodes has an effect on all of us that shoot fireworks. Aside from the basic moral idea that you should not be hurting people and causing damage with your fireworks this kind of incident affects all of us. More accidents equals more regulation and higher insurance costs. It is not hard to build racks that do not fall over. To know if the rack you built will not fall over you have to explode a shell in a mortar in the rack. I also suggest having the adjacent mortars loaded with shells because this is the way it will be when you are using them in a show.

When a shell explodes in a mortar that is all that should happen. It has happened to me and it was a nonevent that had no effect or delay on the show because nothing else fell over. That is the benefit of having racks that can withstand an in mortar explosion and not fall over and scatter mortars.

 

[cduesman]

The farm that hosted the event posted this on their facebook page.

"On behalf of Lavon Farms we would like to report that everything is ok at our Plano Dairy Farm. At no time were any of our family, farm personnel, animals, or structures ever in danger. The Plano Fire Department did a great deal of planning and preparation to ensure that any mishap could be contained. We want to commend the Parks and Recreation department for the great coordination with the world’s finest First Responders to ensure the public’s safety. God Bless America and Happy 4th of July 2020."

I haven't seen any daytime pictures of the event before or after.

 

[Blaster]

I am also glad that no one was hurt. If the racks were compliant with NFPA 1123 4.5.7 through 4.6.11 the other tubes would not have been scattered causing several shells to explode on the ground. This kind of preventable accident should not be happening. One mortar exploding scattering other mortars causing shells to be propelled in random directions is a major cause of damage, injuries and high insurance premiums that make all fireworks more expensive. The guy that is shooting out of racks that fall over when a shell explodes has an effect on all of us that shoot fireworks. Aside from the basic moral idea that you should not be hurting people and causing damage with your fireworks this kind of incident affects all of us. More accidents equals more regulation and higher insurance costs. It is not hard to build racks that do not fall over. To know if the rack you built will not fall over you have to explode a shell in a mortar in the rack. I also suggest having the adjacent mortars loaded with shells because this is the way it will be when you are using them in a show.

When a shell explodes in a mortar that is all that should happen. It has happened to me and it was a nonevent that had no effect or delay on the show because nothing else fell over. That is the benefit of having racks that can withstand an in mortar explosion and not fall over and scatter mortars.

For the most part, I agree...

But some of the issue has to do with the power of the shell too. I've had shells that are the exception to what I expect to see in a mortar failure (not sure what was IN them, but have found a Much higher level of destruction in particular shells). I'm not sure ANY rack could withstand what I have pictured (and mine are all NFPA as required by my state).

This was a 5" Flower King shell that turned the mortar inside-out and destroyed many adjacent tubes. (because of it being in my trailer, it could not scatter tubes that fired elsewhere, but again in any rack set-up I do, I'm not confident that it Couldn't have )

 

[CFD902]

I had a 5inch flower king shell go off in a fiberglass tube this year destroying the whole pod of racks. The force of the explosion cause tubes to fly over 250 feet from the blast area and knocked over the pod of 5inch next to it. After the investigation was complete we fired the rest of the show with the lights on in the ball field and watched 2 shells go up, come down and never go off, 2 shells go up come down and go off on the ground.

The show was inspected by the local and state FM before it went off, so we were good.

My outcome is
1 thank god we were efiring cause someone would have gotten hurt
2 will never use fiberglass again
3 flower king products suck cause its not the first time

 

[BigTopCanada]

I know exactly what you mean about some shells being more powerful than others. I have found that non salute shells that have a high content of metal powder (even if the metal powder is in stars) produce a much more powerful in mortar detonation. Of the non salute shells I sell Silver Wave produces the most powerful in mortar detonation because the stars have a high aluminum/potassium perchlorate content. I learned this by chance because over the years I have tested many rack designs. As a result I use the Silver Wave shells when testing. Also shells that have a high flash powder content in the burst will behave like this. This is not a factor for me because the shells I import do not have a high flash powder content. Because of the regulations in my country I have to have very tight control on the chemistry of my fireworks.

In your trailer setup you actually did accomplish no mortar scattering or hazardous redirection of the mortars.

I also have trailers and when mortars are dense packed as close as yours the burst will flatten adjacent mortars causing those shells to be unable to get out. If the shell that can not get out of the mortar and is ignited it will detonate in the mortar. Also with mortars that close together you can get propagation sometime referred to as sympathetic detonation when the shock from an exploding shell causes the shell next to it to explode. This happens because the containment effect of the shell being in the mortar when it explodes increases the burning speed of the shell contents producing a more powerful explosion. I do not allow the use of salute shells in any dense packed mortars and my trailers have 1/8" mild steel walls with the mortars a minimum of 1 1/2 inch from the steel wall. The science behind this is 1.3G fireworks will not blow a hole through 1/8" steel even in a UN6b test where 3 cases of shells buried under a meter of sand are ignited sitting on top of a 1/8" steel witness plate.

If you moved the mortars further apart ( I am thinking another 1/2") it would reduce the effect on the adjacent mortars to the point that they would not be flattened enough to stop shells from shooting out of them as long as the shells are actually 1.3G not 1.1G . I would test it by using the most powerful non salute shell you use. I know the additional spacing is sometime impractical but if the mortars are contained within a wall and they cannot get out the same thing is accomplished, mortars that only shoot up. Also any containment that can be removed from the design will also reduce the effect on adjacent mortars. I have come to think rod is much better than any flat shape like angle or bar. I built all my trailers with steel square tube, bar and angle and I am now rebuilding them to eliminate the flat surfaces that the explosive forces act upon so well. Mortars can be bolted to the floor of the trailer completely eliminating the frame structure in between them.

For salutes the mortar separation needs to be the diameter of the salute otherwise both flattening of adjacent mortars and sympathetic detonation can occur. This means 3 inches mortar separation for a 3" salute. Any closer than this and a good quality 3" salute will flatten the adjacent mortars and possibly cause sympathetic detonation of the adjacent salutes. My 3" salute racks have a separation between mortars of 3 3/4 inches because they are designed to nest into each other for compact storage and transport.

Separation is used in the design of 500 gram cakes in the USA. A 1/2 separation is required between tubes. back about the late 1990s or early 2000s I was involved in some testing of tubes with the original 1.75"Rambo Kid cylinder shells. The tubes were cardboard glued into a particle board base. At 5/16 of an inch or less an in mortar detonated shell would blow apart the adjacent tubes. At 1/2" there was no damage to the adjacent tubes.

Over the 20 years that I have operated my business my racks have been used by my many customers. There have been several in mortar detonations usually caused by operator error loading a shell. None of them have resulted in a rack falling over or mortars scattering. One badly executed fireworks show resulted in a 6" shell exploding in the mortar. The rack was still intact and they shot the remaining shells out of it. In another incident a 6" shell detonated in a rack and the only effect on the fireworks show was that a firing module was blown across the barge disconnecting a few Ematches. I have seen all of the results of in mortar detonations described above because I have seen them when testing racks and trailers.

The main points are sturdy construction, mortar separation and reducing containment around the mortars. The most important thing is testing the design of your racks to know that shells won't shoot into the audience if a shell detonates in a mortar. I have tried and failed more than once designing a rack. You know what will result from an in mortar detonation when you test your rack. It is also important that the rack design does not produce any shrapnel. I once tried to make a really strong rack and blew the head off a 7/16" grade 5 bolt that was a very hazardous piece of shrapnel.

For materials steel and aluminum both work. You can also build racks from wood that will not blow apart or fall over but it must be good solid strong wood. Hardwood pallet lumber is an economical source of strong wood. You can buy it rather than get it by taking apart pallets. Also if you have SPF lumber (Spruce, Pine Fir) and you can select the really heavy dark heartwood boards that will work too. Fir plywood is very strong and useful in rack design. The light white and wide grained boards will not work. Wood should be glued and screwed together. Once again you must test your design.

I have to know this information because in my country we have what we refer to as the indestructible rack standard. Racks must be able to handle an in mortar detonation and still function without dangerous redirection of the mortars. This of course means no blowing apart or falling over. if your racks do not meet this standard we must triple the legal distances to shoot shells. Because I sell ship shows and supply the racks to shoot them my racks must meet this standard. It would appear that the same standard has been added to the most recent version of NFPA 1123.

I am taking the time to share this information because it would be a great thing if we stopped racks falling over and blowing apart.

Fireworks are supposed to be a spectacular happy time not an accident.

 

[Jeff D]

Very Interesting. Only thing I could think of for delays being placed into shell chains in racks is because a lack of enough firing system to fire it electronically. No reason for hand lit shows in these days. Deadman/Pause/STOP doesn't work once the fuse is lit!

 

[BobinNC]

Delay chains are common in large electrically fired shows, due to the time and challenge of having every shell be individually e-matched. They add some inherent danger, as pointed out, so best to do them carefully, like salutes. Best is to use 3" chains when you have larger shells as well, as then they will be much further from the audience, as distance is your friend. And strudy racks are good, as is the ways groups of racks are placed and connected, but a large shells can do a lot of damage, no matter what. And while tubes spaced further apart does help, having moved some SC type racks (1.5" between tubes rather than 3/4"), I am not sure that for smaller (3"), color shells it is needed. In many shows, I have never seen a 3" color shell CATO damage the tube and rack enough to change the aim of any tubes. For larger shells, I try to keep the pods of racks smaller and more stable (squares are good), so that they will withstand a CATO. But distance is really the key, if you have 100 or more feet /inch, you will minimize the rsik to the crowd, I have not seen many cases of crowd injuries when that was done, but quite a few at 70 foot/inch.

As for the fires, anyone who has been to MAFF knows that they can be common, but most of the time, you try to fire the show and then put the fires out afterwards or take a break to do it. Not sure where the in show timing this was, but if near the end of the show, I would likely just wait until after the fanale to put them out if not unsafe to the crew or crowd. I have seen finales start 10 to 20 fires if the conditions are bad, due to the amount of burning paper, just from the launch, much less the shell stars. We once started a fire almost a mile away from a show when the wind picked up right at the end of the finale. The fire was not seen until almost an hour after the show. But it was within the display site property, and we had good fire controls crews, although they were not in much of a hurry to put it out. I think we disturbed their post show party.

Bob