Dive Cylinder Explodes - Sydney

[Wookie]

Wookie, thanks for the info. I am very surprised that the 8" reinforced concrete tank came apart, but I take your meaning of hydraulic pressure.

In the second example I guess the main reason that the SS tank did not fail was the significant reinforcement via the internally welded bars. So is it the combination of water and reinforced SS, or would just a reinforced SS tank be more effective.

I would assume that anything that directs the force of the explosion up is going to make the operator's (and bystander's) day significantly better. In the second example, It was a piece of "reinforced PVC pipe". Now, I don't know what reinforced PVC pipe is, but I want some. Looks to me like it doesn't take much of a hint to make filling safe, a suggestion of "blow up not out" seems to do the trick, although I am basing that on a single incident.

But I know a little about the Mako fill station discussed earlier. They don't work by containing the blast, they work by directing the blast up not out, and by keeping the shrapnel from getting loose.

 

[Peter69_56]

I would assume that anything that directs the force of the explosion up is going to make the operator's (and bystander's) day significantly better. In the second example, It was a piece of "reinforced PVC pipe". Now, I don't know what reinforced PVC pipe is, but I want some. Looks to me like it doesn't take much of a hint to make filling safe, a suggestion of "blow up not out" seems to do the trick, although I am basing that on a single incident.

But I know a little about the Mako fill station discussed earlier. They don't work by containing the blast, they work by directing the blast up not out, and by keeping the shrapnel from getting loose.

My thought is anything is better if it changes the explosive force upward over a tank sitting the open, even if it only partially changes it..

 

[Diving Dubai]

@Peter69_56

I've just been looking at a Bauer cylinder filling containment cabinet. The Cabinet itself is a steel box without welded seams (as they are a weak point. The cylinder is placed within a PVC tube affixed to a bottom hinged door. All the whips and connects are enclosed when the door is shut.

Although conjecture on my part, I believe the PVC tube as well as locating the cylinder is the first line of defence against a failure that contains or slows fragments down inside the box. The escaping gas from the cylinder will expand inside the box, thus losing some energy as it pressurises the 1 atm air in the box. The steel of the cabinet is sufficiently thick but malleable to allow deformation to control the shockwave, and there is I suspect an OPV which allows the release of pressure in a controlled way.

IF you want to see great examples of destructive over pressure being contained, watch the following video of an A380 blade off test.

 

[Peter69_56]

@Peter69_56

I've just been looking at a Bauer cylinder filling containment cabinet. The Cabinet itself is a steel box without welded seams (as they are a weak point. The cylinder is placed within a PVC tube affixed to a bottom hinged door. All the whips and connects are enclosed when the door is shut.

Although conjecture on my part, I believe the PVC tube as well as locating the cylinder is the first line of defence against a failure that contains or slows fragments down inside the box. The escaping gas from the cylinder will expand inside the box, thus losing some energy as it pressurises the 1 atm air in the box. The steel of the cabinet is sufficiently thick but malleable to allow deformation to control the shockwave, and there is I suspect an OPV which allows the release of pressure in a controlled way.

IF you want to see great examples of destructive over pressure being contained, watch the following video of an A380 blade off test (Skip to 4:00 for the quick version)

Yes I see your point, the germans know their stuff and if thats how they do it, I would bet its a good approach. I understand their logic behind their design

Ok wookie, I stand corrected. Pity I cant afford the Bauer system.

 

[Jack Hammer]

The majority of water baths and protective "containment" systems I've seen at fill stations have been either a big plastic or a big galvanized steel tub, basically a horse trough. I sincerely doubt these would direct energy up and away and believe they would just add more shrapnel in the event of an explosion. I only recall seeing one made of concrete and most the tanks were filled outside of it.

Doesn't really matter if it works or not if they're not really used properly

 

[tbzep]

But I know a little about the Mako fill station discussed earlier. They don't work by containing the blast, they work by directing the blast up not out, and by keeping the shrapnel from getting loose.

Simple physics allows a much smaller and lighter unit to keep people safe, rather than having to fill in a massive bank vault of a station. Our fill station weighs over 1,000 lbs, so I can't imagine the heft of a unit designed to completely contain a blast.

 

[Wookie]

Simple physics allows a much smaller and lighter unit to keep people safe, rather than having to fill in a massive bank vault of a station. Our fill station weighs over 1,000 lbs, so I can't imagine the heft of a unit designed to completely contain a blast.

Ah, but they aren't built to keep someone safe, they are built to meet a government specification, specifically an NFPA rating. I've built my own for far less than a containment fill station costs, and am ready to give it to someone.

 

[Diving Dubai]

Simple physics allows a much smaller and lighter unit to keep people safe, rather than having to fill in a massive bank vault of a station. Our fill station weighs over 1,000 lbs, so I can't imagine the heft of a unit designed to completely contain a blast.

It doesn't need the be massive in mass, it just needs to be designed well. You need materials that have some give and elasticity to absorb the blast and slow the shock wave and dissipate the energy.

Crash a 1950,s car into a modern day car and see which protects the occupants the most

 

[BRT]

It doesn't need the be massive in mass, it just needs to be designed well. You need materials that have some give and elasticity to absorb the blast and slow the shock wave and dissipate the energy.

Crash a 1950,s car into a modern day car and see which protects the occupants the most

2005 Chevrolet Impala/Curb weight


3,465 to 3,606 lbs


characteristic dimensions: outside length: 4968 mm / 195.6 in, wheelbase: 2921 mm / 115 in.
reference weights: shipping weight 1431 kg / 3155 lbsestimated curb weight: 1510 kg / 3330 lbs.
1955 Chevrolet (USA) Bel Air 2-Door Sedan full range spec

There may be another reason too. Less weight spread over more space in the older vehicle.

 

[clownfishsydney]

Some more information about this accident. The tank was aluminium, confirmed as a Sea Hornet brand (Australian dive company). The tank would have been made by CIG Gases (I am reasonably sure) and must have been at least 23 years old as they stopped producing tanks with Sea Hornet name etched/stamped on them about then. I am 99% sure that it was a 6351 alloy tank.

The tank was out of test and was not being used for scuba diving, but for paintball. This information again comes from an impeciable source.