Burst disks???

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When the cylinders went back to your LDS after hydro, and your LDS VIP'd them, weren't their cylinder-to-valve O-rings replaced and their burst discs replaced, too? Isn't this "normally" done?

I've not heard of a shop that replaces burst disks without direction from the tank owner unless it is a complete valve service. On the other hand the cylinder to valve o-ring has been done every time.

Since I do my own valve service it is not an issue.
 
So tonight I had a burst disk let go while in my hotel room. I had the tank filled at 9am and it let go 14 hours later. The tank is a HP100 and it had hydro and VIP 3 months ago. What concerns me the most is this had also happened with another one of my HP100’s a month ago. Ironically after staying at the same hotel and filled by the same people. The tanks were at 3600 psi after the fill each time. Is it normal to check the burst disk at hydro and VIP? The first tank is 12 years old, and the one today has a born on date of 6 years. After having this happen twice in a month I’m tempted to have all my tanks burst disks replaced. Advice?

This is why you should replace them or have them replaced at hydro. They don't last forever. Personally, valves are currently so cheap, I just replace the valves at Hydro. That way I get not only a new burst disk but entirely new valve. A new valve is about as cheap, possibly cheaper, than what it costs me to pay the shop to do a full valve service plus change the burst disk. I have no interest in doing it myself. Been there, done that.
 
I've not heard of a shop that replaces burst disks without direction from the tank owner unless it is a complete valve service. On the other hand the cylinder to valve o-ring has been done every time.

Since I do my own valve service it is not an issue.
I do. Unless the customer states not to. I am a small minority that doesn't sell air. While the bulk of my fills are 32%, I do a large amount of trimix. Burst discs don't blow at 1000 psi, they blow when they are full or nearly full. Nobody wants to pay for OC trimix costs as it is. It is worse when you pay double because you lost a disc. $5 for a burst disc is very cheap insurance.
 
So tonight I had a burst disk let go while in my hotel room. I had the tank filled at 9am and it let go 14 hours later. The tank is a HP100 and it had hydro and VIP 3 months ago. What concerns me the most is this had also happened with another one of my HP100’s a month ago. Ironically after staying at the same hotel and filled by the same people. The tanks were at 3600 psi after the fill each time. Is it normal to check the burst disk at hydro and VIP? The first tank is 12 years old, and the one today has a born on date of 6 years. After having this happen twice in a month I’m tempted to have all my tanks burst disks replaced. Advice?
Valves should be serviced no less often than the hydro schedule. Burst disc replacement occurs during valve service....

If you want to be pedantic, legally they MUST be replaced within 10 years of the manufacture date of the burst disc itself. Replace at hydro is easier to keep track of and for a part that cheap it's not worth tracking. Per CGA S-1.1
 
Ain't burst discs so archaic and unnecessary? I am glad we don't have them and don't use them in the free world.
 
Ain't burst discs so archaic and unnecessary? I am glad we don't have them and don't use them in the free world.
In the US all pressure vessels over ~500psi are essentially treated the same with regards to pressure relief devices regardless of application. For a breathing application many countries have actually banned the use of a pressure relief device, but I do not see anyone pushing for legislation to change on that front in this country.

Many people break the law every time they drive without a seatbelt or exceed the speed limit, many divers break the law by removing the relief device in their diving cylinders. I'm not advocating for it, but the parts do exist.
 
Many people break the law every time they drive without a seatbelt or exceed the speed limit, many divers break the law by removing the relief device in their diving cylinders. I'm not advocating for it, but the parts do exist.
I'm just saying...
Screenshot 2022-08-26 151830.jpg
 

Thank you for the great information. I find this part the most useful:

"Changing a burst disk that has not actually ruptured can be troublesome, especially if the valve has never been pressurized. When a new disk is installed in a valve, the compression of the disk by the hollow retaining nut can cause the edges of the disk to extrude slightly into the threads of the over-pressure outlet on the valve. When the retaining nut is removed, a disk that has never been pressurized (and even some that have) can be a challenge to dislodge and if that's the case then using a small screw extractor is likely the best approach. An alternative method is to first pressurize the valve to the service pressure of the cylinder or the burst disk, whichever is lower. This will cause the edges of the disk to recede slightly from the threads, then drain the cylinder and remove the hollow retaining nut. Once the nut is removed, wrap a towel on the valve and start rapidly pressurizing the cylinder again... the disk should blow out of the valve and be safely captured by the towel. Look down in the outlet to make sure both the disk and the washer underneath it came completely out. Look carefully, if the small washer underneath the disk was made of clear plastic it can be very difficult to see. You should be able to use a brass o-ring pick to carefully remove any components that remain."
 
https://www.shearwater.com/products/teric/

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