Air Tank Safety

[mahoak]

Short story first, Junior Program at our local club wants to invest in some air rifles especially for the younger kids due to being available in shorter and and lighter models than our small bore rifles. Board chairman seem deftly afraid of scuba tanks for filling said air rifles. We need to come up with some documentation supporting the safety of using scuba tanks while following guidelines like strapped to racks bolted to wall to prevent falling, and other normal precautions.

The NRA Air Program Director is looking but didn't have any readily available. Anyone have any ideas where to look. Best I found in internet searching was on the Pilkguns site, but doesn't address the issue directly. Anybody gone through this at their club or any other insight or ideas that may help?

Are there any excess liabilities, insurance or otherwise with having compressed air stored on site.

Any help will be appreciated.

Mike

[jhmartin]

The board chairman has seen too many Hollywood movies where the hero causes a massive explosion shooting at a SCUBA tank.

[BigAl]

The Air Rifle/Pistol club I shoot at here in the UK simply keeps the in use tank (we have a couple of 300 bar to allow for refilling) in a small cupboard in the corner of the clubhouse area. The cupboard is locked when not in use. The tank wears a boot so that it stands up on its own. To fill a rifle cylinder you just lift the tank out of the cupboard, as otherwise it is quite difficult to see the fill gauge, and you do not want to fill a 200 bar cylinder to 300 bar. Replace after filling. Pistol cylinders fill OK while in the cupboard. The only rule we have is no juniors to fill cylinders, although most of our juniors who have been shooting for a while are probably more competent than some of the older members. But then seventy to eighty percent of the clubs regular junior shooters are in various national squads, GB or Home Countries.

If treated responsibly then SCUBA tanks are perfectly safe. You only have to look at the environments that they are regularly used in for their intended use, especially commercial diving in say the offshore oil and gas industry such as we have in the North Sea. Coming from one of the main ports for the southern sector we would hear if there were any serious accidents involving this type of equipment. One fellow club member is a Dive Master for one of the offshore oil/gas companies. As jhmartin says too many hollywood films. I have a couple of 207 bar tanks at home and I have no worries about them exploding.

Alan

[peashooter]

Personally I wouldn't fill a 200bar cylinder from a 300bar cylinder without a regulator.

[BigAl]

Personally I wouldn't fill a 200bar cylinder from a 300bar cylinder without a regulator.

If you follow a sensible filling routine then you should have zero issues filling to 200 bar from a 300 bar tank. Even if you were to just open the valve fully and let the cylinder fill it isn't going to explode. All of the cylinders used on guns, fixed or removable, have safety fail systems fitted to ensure that the cylinder simply vents in a safe manner in the event of over filling. OK you will have to replace the cylinder but thats all. I work for an airgun specialist firearms dealer, who has been selling PCP air rifles since Daystate first introduced them commercially to the market in the 1980's. In that time he must have sold in the tens of thousands of rifles. The number of failures due to overfilling can be counted on the fingers of one person. Actually I can only recall one case of a catastrophic failure of a rifle. That was not caused by overfilling with air but filling the gun with Oxygen. This user worked in aviation and so had access to oxygen at work, which when the oxygen at around 200 bar came into contact with the small amount of grease in the gun spontaneously ignited when he fired it, blowing up the gun. The gun was a Theoben Rapid 7, and yes I have seen the pictures which were not pleasant to think about.

Alan

[rmca]

One argument that usually calms people who watch too many hollywood movies is the Olympic aspect of the game.
Mention that that's how they charge the rifles/pistols at the Olympics. That usually calms people down.

As mentioned before, check local regulations on cylinder testing and certification and storage.

A jig bolted to a wall in a closed room or inside a locked cabinet should be enough.
Remember that those thanks are made to be on the back of humans going into (usually) salt water. So they last even a longer time with no contact with water.
If you can, try to get thanks that have a pressure indicator on them. It's the best thing for long term use.

Hope this helps

[mahoak]

Thank you to all who replied. Confirms what I thought. Also found that the NRA has posters available regarding the safe use, filling and handling of both compressed air and Co2. They also provided the source of the fear factor, 2.5 million tanks of an aluminum alloy, out of which 29 tanks burst worldwide. The alloy is no longer used.

[rmarsh]

One thing you might consider is some kind of a strap or stand that secures the scuba tank. I think it would be rather difficult to cause a dangerous leak by knocking one over, but a tether of some kind would remove that worry. I use a nylon strap with dog leash latch which wraps around my tanks and secures them to the wall. That and as another person said, no Jr's filling tanks, and you should be fine.

[mtncwru]

In addition to the risks that come with filling cylinders off the tank, the main danger with SCUBA air tanks is that if the big valve at the top of the tank breaks off, the tank will turn into a ballistic rocket. Mythbusters tried this out a few years back, and managed to punch through a cinder block wall with energy to spare (https://www.youtube.com/watch?v=ejEJGNLTo84). Take care in handling and moving them: two hands on the smaller ones, and use a dolly for the bigger ones; if you are using a dolly, you should use a chain/strap to ensure that the cylinder doesn't flop off the dolly.

I would go a little further than Mr. Marsh's polite suggestion about a strap and say that it, or some kind of rack/bracket, is mandatory for storing your tanks. At my hospital we have a big, heavy-duty, purpose-built, metal rack for our oxygen tanks that won't be flopping over sideways no matter what the San Andreas does this week; I did a quick Google search, and there are plenty of ideas for home brew options that won't run you the $200+ we paid for ours. Wall-mounted brackets with straps work pretty well, too.

[dahigg]

I've been to very few ranges that don't use SCUBA tanks to fill air cylinders. A lot of the time, those SCUBA tanks are just sitting on the ground, not secured by anything...look at most of the NCAA ranges.

[Rover]

It's easy. Just switch to SSP's. (Heh, heh, heh.)

[jhmartin]

Simple - Easy
http://www.usasafety.com/cylinder-brackets-c-21.html

I use these for our CO2 & SCUBA cylinders.

[TerryKuz]

I saw a shark blow up from a air tank and a shot from a M1. It was a big shark, and it blew sky high. I think it was around 1975 in small island community of Amity.

[jhmartin]

Steven, that is completely unbelievable. It can’t happen. A shark does not bite down on a SCUBA tank and explode like an oil refinery.” He said, “I don’t care.” He said, “If I have got them for two hours, they will believe whatever I do for the next three minutes because I’ve got them in my hands, and I want the audience on their feet screaming at the end, ‘Yes, yes! This is what should happen to this animal!’