Safety radius?

[Richtee]

What is an acceptable distance from the firing area for spectators? I will be using no more than 3" shells. Have some fountains and a rack of red/white/blue flag I hope works, but nothing too hot in those.

 

Is there standards on this? My gut tells me somewhat over the height of the 3's... 300-400 feet. But that seems a long way.

[jacob]

Here's the NFPA guidelines for minimum display site radius,

 

 

< 3 in. 140 ft.

3 in. 210 ft.

4 in. 280 ft.

5 in. 350 ft.

6 in. 420 ft.

7 in. 490 ft.

8 in. 640 ft.

10 in. 700 ft.

12 in. 840 ft.

> 12 in. AHJ approval

 

Personally I'd want an audience as far back as they can get and still see the show, which should be more then 210'.

[Richtee]

Here's the NFPA guidelines for minimum display site radius,

 

 

< 3 in. 140 ft.

3 in. 210 ft.

4 in. 280 ft.

 

Personally I'd want an audience as far back as they can get and still see the show, which should be more then 210'.

Why thank you Sir! I have 300 foot available easy. That's what it'll be then.

[ST1DinOH]

i'm not a big fan of the under 3 inch guidelines...

 

the way i read that chart it's 70 feet per inch ID of tube. so a 1 inch tube means you should be back 70 feet.

 

viewing a front of color pearls from 140 feet away is dumb.

[Richtee]

viewing a front of color pearls from 140 feet away is dumb.

I was not clear... The shells will be launched from 300 feet. The fountins and etc... 100 foot is safe. There's nothing in the comps that even on a bad day could cause harm...well from a hundred feet anyway.

[MrW]

Hi all, sorry to drag this one up.... I'm just chasing some info on site setup (that includes 2", 3", 4" & 6" ball shells + 4oz &3lb rockets-all home made).

I know the minimum site radius as stated above, but that means I need 4 setups at various distances. What is the normal for setting a display of various sizes? As a look on the various internet shows it seems they lump then together in one site. I know I can't shoot the 2" & 6" at the same distance, but would be a happy medium (or keep to these guidelines to ensure 100% crowd safety)? Thanks in advance.

[Mumbles]

The site radius as given above are minimum distances. There is no reason that shells can not be shot farther away. In the displays I've worked on, most of the shells (3-6") are in one area at a distance suitable for 6" mortars. Anything larger is generally fired electronically, and placed farther back, isolated from where the shooters are.

[nater]

For our shows, the setup depends on the site. We have a few sites large enough we can place 3s 300' from the crowd and 6s at 600'. We handlight most shows, so the distance means a few things. It is harder on the lead and lead safety to keep an eye on everyone, but radios help. It is also means we needs to have enough shooters because the racks are spread out more. The flip side, is that the extra distance between racks makes it much safer for the shooters. An malfunction on one station is less likely to affect another station. Also, done right you can use the depth to your advantage to get the most out of small shells and frontage. You can also use the depth for some neat effects.

 

We have other sites that are smaller and the setback is placed at the distance for the largest shells. This makes the small shells appear even smaller. However setup and tear down are easier.

 

Once you know your minimums, the rest depends on your site. Please keep in mind, the 70-100' per inch of mortar only applies to shells fired out of vertical mortars. Angles change the requirements and rockets need much, much more room to be fired safely. 3lb and up especially since the falling stick and tube can cause major damage to property and might be fatal if it hit someone.

[MrW]

Cheer Mumbles & Nater for the input. I will base it on the advice, my 2" rack will be easier to shift so I will maintain min site distance, but will keep the others at the required distance. My site is 500acres of paddocks on one of our properties and will be for my old mans birthday, so only a crowd of about 50-100 people max. Will keep the advice on the rockets, what's a good angle of declination for the rocket racks? I was thinking 15-20 degrees off vertical. And current weather forecast is the wind is blowing away from the crowd, as a added bonus.

[nater]

I usually fire rockets about 10 degrees off vertical. The wind blowing away from the crowd is good for general fallout, but bad for rockets. Stick rockets will shift to fly into the wind. Proper stick length and fast rockets suffer from this less, but it is something to keep an eye on. 500 acres is plenty of space, so be extra careful with the large rockets and enjoy yourself.

[MrW]

Cheers Nater, I will probably launch from the 6" shell area. I didn't even think about the fact that it would act as a wind vane and head into the wind. Thanks for bringing up a good point. Thanks again.

[Arthur]

In the UK we usually group similar tube diameters at similar distances. So 6mm pearls are much closer than the shells.

 

We make a good attempt to use 1 meter of distance per millimeter of bore diameter..

[MrW]

That makes more sense , and an easier way to remember 1m/1mm of bore diametre. Thanks Arthur.