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View Full Version : AMR car blows up


Walter Suiter
02-21-2018, 05:16 PM
This will be an interesting situation to watch unfold.
https://www.firerescue1.com/fire-attack/articles/375959018-NY-ambulance-fire-explodes-oxygen-tank-sends-shrapnel-flying/?NewsletterID=597628&utm_source=iContact&utm_medium=email&utm_content=TopNewsRelated1Title&utm_campaign=FR1Member&cub_id=[cub_id]

Initial reports are a ruptured O2 cylinder is in the debris, supposedly from the car that burned.
If this turns out to be true, why didn't the safety on the valve let go before the cylinder reached sufficient pressure to rupture?

I'd love to see the dates on that cylinder and know who "inspected" it.

Denny Shira
02-21-2018, 07:26 PM
Walter, Maybe Junior inspected it? Glad no one was seriously hurt. Cause of fire most likely electrical. We lost a couple of rigs that way.:(

John ED Renstrom
02-21-2018, 09:18 PM
so I wounder how the O2 tank blew up. didn't any one tell them O2 dosen't burn

Paul Steinberg
02-21-2018, 10:20 PM
Heat makes compressed gasses expand. Expanding gasses can cause the vessel that the gas is contained in rupture. If that gas supports combustion, then an explosion ensues. Simple 1st year physics.

Chemistry 101: Oxygen is not flammable. High concentrations of oxygen used during surgeries are a potential fire hazard for patients, but that doesn't mean the O2 gas itself catches fire. ... Oxygen makes other things ignite at a lower temperature, and burn hotter and faster. But oxygen itself does not catch fire.

Peter Grave
02-21-2018, 11:40 PM
Oxygen combined with other material present in an ambulance could ignite with a boom. I think I have told the story before of the 1964 Cadillac Superior Hi Top Lansdale Pa. Volentier Medical Service Corps. bought in early 65 the rig was scorch burned around the attendants seat and above it Cabinets ,headliner seat rear right side door panel and squad bench. I was told a Corps Member lit a cigarette with the oxygen on he was badly burned with the flare up.

Walter Suiter
02-22-2018, 01:28 AM
Been pondering on this one all day and there are too many missing pieces in the report. I'm wondering if AMR is using composite cylinders which would more easily explain the rupture.

Initial cause of the fire is of little import to the overall event/explosion.
I've been hands on with oxygen cylinders that went through a damn hot fire in a blacksmith shop, and acetylene bottles as well, and each and every one of them the safety ruptured preventing rupture.

At this point, and until I talk to some AMR people, I just can't account for the rupture of an Qxygen bottle. Best speculation I can do at this point is an initial electrical fire lit off something in the compartment getting the area of the cylinder to above 165f which would melt the alloy of the CGA 3 or 4 over pressure fitting on the valve and allow decompression of the cylinder.

That would definitely lead to an Oxygen rich atmosphere in the compartment rapidly, leading to very high temperatures which probably converted the compartment itself to fuel to combine with available Oxygen. This could have happened within seconds.

We pretty well know the compartment lost all structural integrity early in the event because a cylinder took flight for want of a better term. We also know the ruptured cylinder was found away from the ambulance residue.

Condition of the cab post fire strongly says the cylinder didn't rupture within the vehicle, or left the vehicle in the process of rupturing. My thinking is the vehicle carried 2 cylinders, 1 in service and 1 spare, not connected, and the spare is the one that ruptured and flew. I'm still stuck on why the CGA Safety on that cylinder failed to depressure the cylinder prior to rupture or flight. If the ruptured cylinder was steel, the burst strength should have been over 10,000psi and I question if that happened during the short fire duration before the cylinder flew.

Too many possibles and not enough information. Pretty much my usual starting point.

Denny I doubt Junior ever did more with a cylinder than lean on it, or tap his stupid pen on it. His mother raised him to be an executive. He did once pick up a 10 pound bag of crushed ice all by himself to take to a party, and needed a couple days off to recover.

Denny Shira
02-22-2018, 09:56 AM
Having all this technical expertise available is one of the things that is so great about this club. Having handled oxygen cylinders since the age of 16, i knew about the basic rules for handling them, but the insight and knowledge of other members here is amazing.
thanks to Paul, Peter and Walter for your input. A very scary scenario in Buffalo.
I am extremely grateful that there were no serious injuries. :thumbsup:

Blake Sherwin
02-22-2018, 10:07 AM
On the bright side at least it was in a maintenance bay and not carrying a patient.

John ED Renstrom
02-22-2018, 11:47 AM
Were they carrying compressed gas or liquid O2? My guess is the tank blew first. When it left the side of the rig it caused a electrical fire that got really hot in the rich mix. Nothing in an ambulance to burn except fuel that could get hot enough long enough to melt the safety on the tank,let alone hot enough to blow It would still be in its own compartment with the lines out side. The pt compartment.

Paul Steinberg
02-22-2018, 12:49 PM
Here is another ambulance fire, that destroyed a building....

http://www.nj.com/salem/index.ssf/2018/02/at_least_2m_in_damage_after_fire_tears_through_amb .html

Today, most of the portable oxygen cylinders are aluminum, not steel. As for safety release valves, I have looked at the steel and aluminum ones that I have, and I see no visible safety release valves.

Walter Suiter
02-22-2018, 04:32 PM
Were they carrying compressed gas or liquid O2? My guess is the tank blew first. When it left the side of the rig it caused a electrical fire that got really hot in the rich mix. Nothing in an ambulance to burn except fuel that could get hot enough long enough to melt the safety on the tank,let alone hot enough to blow It would still be in its own compartment with the lines out side. The pt compartment.

Oh contrare, steel, actually the iron component of steel burns in an Oxygen rich atmosphere. That is exactly how Oxy/fuel torches and lasers cut steel. Aluminum, fiberglass, styrofoam and wood burn very quickly when Oxygen enriched.
A slow Oxygen leak in the presence of wood or foam will turn them into rocket fuel speed burns. It was quite fun back in the 60s watching baby nurslings learn how fast a mattress under an Oxygen tent cooked off when ignition was supplied.

Oddly, liquid Oxygen is far less likely to be a culprit in this event, both because liquid is constantly vented leading to a 10% content loss per day in the Dewer unless Oxygen is being drawn from the Dewer. Dewers are essentially LOW pressure insulated bottles without tops.
http://www.airproducts.com/~/media/files/pdf/company/safetygram-6.pdf


The safety rupture disk in a Medical Oxygen valve is built into the base of the valve between the threaded portion that goes into the cylinder and the valve seat. Medical valves may or may not have 165 melt fuses, depending on manufacture.
Lack of a heat fuse may well have led to the rupture of the AMR cylinder. The overpressure disk should have released and depressured, but all components do fail.

John ED Renstrom
02-22-2018, 09:57 PM
in all my years of handling bottled O2 I have never seen a incident with one

Walter Suiter
02-22-2018, 10:54 PM
in all my years of handling bottled O2 I have never seen a incident with one

Ever seen a pair of geniuses trying to remix a cylinder of C-25 welding gas because it separated sitting in storage?

Bill Anderson
04-06-2018, 01:24 AM
It didn't say what size cylinder. Most companies today have gone to aluminum D and E cylinders.

John ED Renstrom
04-06-2018, 10:39 AM
It would be a soldered slug in the brass valve. But even if the tank blew there would have to have all ready been a large fire. The sudden realise of that much o2 would cause the fire to flair up not explode. The tank going threw if it was not secured would appear as if there was an explosion. But it would have been fun to watch the last 30 seconds of the event.