LOx Tank Failure at Toronto hospital

[weeeds]

Anyone have any details about the explosion of the LOx tank at a hospital in downtown Toronto? It looks like the vacuum jacket top head was ripped off but what would cause that to happen in such a catastrophic way?

 

[FacEngrPE]

If the safety system had not worked correctly the tank would be somewhere else and empty of LOX.

The event was most likely started by a leak between the liner and the outer shell. This space is normally filled with loose perlite and then pumped to good vacuum to create the Cryogenic rated insulation.
If this vacuum space gets a small amount of LOX in it the space will overpressure, and blow out the rupture disc. The rupture disc is set to protect the liner from crushing (external pressure). At the time of the video there is still a considerable amount of LOX in the tank, the liner may be torn but if not the boiling lox will be venting out relief valves, so further trouble is unlikely.

It is an expensive failure, as the tank is likely not repairable.

Fred

 

[Sparweb]

Here is what the tank looked like (Google Street-View, screen-capture):

Lots of frozen condensation on the radiator to the right.

http://www.sparweb.ca

 

[davidbeach]

The frozen condensation is a given; seems light given other evaporators I've seen.

 

[waross]

I had to chuckle walking through a SAGD plant. The laggers had insulated everything in sight, including the evaporators for the liquid nitrogen tank.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[EdStainless]

We used to cool drinks in our vaporizers.

LOX does scare me, but this almost a non-event. It is likely that they are using less oxygen these days with less elective surgery going on these days. When the over pressure relief blows it is supposed to vent up a stack, but it looks like the line leaked into the vacuum and blew out some of the vermiculite. MVE (or whoever built the tank) will be able to fix this easily.

I have seen photos of a LOX leak (bottom of tank failure) and the ensuing fire. Cars were reduced to small lumps of ash with only a little iron left and everything else gone. The asphalt parking lot was turned into 6" deep loose gravel. With that much oxygen everything burns.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[djs]

About 15 years ago I installed a control system in a water plant that used ozone. They had two large LOX tanks to supply oxygen to make the ozone. One night a small plane crashed on the plant grounds. The fire ball from the crash got to within 15 ft of the two tanks! Luckily no one was killed.

 

[FacEngrPE]

For anyone planning to work with oxygen pipelines (industrial and medical systems included) ASTM G88 - 13 Standard Guide for Designing Systems for Oxygen Service is strongly recommended. It records many of they impressively scary features of these systems.

During my apprenticeship one of my early encounters with this was watching a Electric Arc Furnace operator using a torch consisting of only 20 ft of 1/2 inch steel pipe, connected to a 150 psig oxygen pipeline. The task was to cut loose some yellow hot steel stuck to the roof of his furnace. The job used up about 5 feet of the torch.