Exactly ! Another good example of the phenomena. Thanks, Quentin.
- Paul North.
Perhaps another example of expansion and heat and pressure involved...and the results: Take an automotive cooling system that is capped with a 15# pressure cap and perhaps it has been running in desert heat with temps above normal boiling point, but not boiling and keeping the cooling system coolant under control...until...one might stop and if....the pressure cap would be removed and of course the 15# of pressure inside the cooling system would immediately drop...the result is a violent "explosion" because the coolant now turns to steam....
Quentin
Paul_D_North_Jr [snips] The portions emphasized by underlining above are common with locomotive boiler explosions. When the crownsheet goes dry due to low water level, it rapidly overheats, loses its strength, and collapses under the boiler pressure. A common example is if a cone-shaped paper cup ('Dixie cup') full of water is held with the outside over an open flame such as a chemistry lab Bunsen burner, the water will boil, but the cup won't burn - the heat is transferred to the water and released by boiling faster than the paper would reach its ignition temperature (or a melting or softening point in the case of steel). However, when and as the water is evaporated and the inside of the cup becomes dry, it will then start to char and burn. The best general explanation is of course this article in Trains - Big bang, no theory Trains, April 1995 page 66 boiler explosions were rare but spectacular ( EXPLOSION, "KING, ED", STEAM, ENGINE, LOCOMOTIVE, TRN ) Also - The night that 4922 blew up Trains, July 1974 page 36 boiler explosion in the roundhouse ( 4-6-2, EXPLOSION, "HERRING, SIMON E.", NYC, STEAM, ENGINE, LOCOMOTIVE, TRN ) That's what happened in the Gettysburg Railroad steam locomotive boiler incident in the mid-1990's - although even that release was akin to a smoky explosion. Steam, steel, and safety Trains, May 2000 page 58 new rules for boiler inspection ( PRESERVATION, SAFETY, STEAM, "WITHUHN, WILLIAM", ENGINE, LOCOMOTIVE, TRN ) [snips]
Big bang, no theory Trains, April 1995 page 66 boiler explosions were rare but spectacular ( EXPLOSION, "KING, ED", STEAM, ENGINE, LOCOMOTIVE, TRN )
Also -
The night that 4922 blew up Trains, July 1974 page 36 boiler explosion in the roundhouse ( 4-6-2, EXPLOSION, "HERRING, SIMON E.", NYC, STEAM, ENGINE, LOCOMOTIVE, TRN )
That's what happened in the Gettysburg Railroad steam locomotive boiler incident in the mid-1990's - although even that release was akin to a smoky explosion.
Steam, steel, and safety Trains, May 2000 page 58 new rules for boiler inspection ( PRESERVATION, SAFETY, STEAM, "WITHUHN, WILLIAM", ENGINE, LOCOMOTIVE, TRN )
[snips]
To complete my portion of the discussion, here's an excerpt from the NTSB report on the Gettysburg RR's boiler explosion -
Special Investigation ReportSteam Locomotive Firebox Explosion on the Gettysburg RailroadNear Gardners, PennsylvaniaJune 16, 1995
NTSB Number SIR-96/05NTIS Number PB96-917008PDF Document (2.1M)
as found at - http://www.ntsb.gov/publictn/1996/sir9605.pdf
particularly, page 19 of the Report (page 27 of 63 of the 'PDF' version) [emphasis added - PDN]:
Postaccident Inspections, Tests, and Research
The flames and hot gases in a locomotive firebox at a temperature of from 1500 °F to 2500 °F heat the firebox sheets [FN
[FN27] The firebox sheets are the metal interior walls of the firebox, which are heated directly from combustion of the coal, wood, or oil.
[FN28] The front section of the crownsheet, which is attached to the rear tube sheet knuckle, usually incurs the initial overheating because it is the highest point in the crownsheet and therefore is the first to be uncovered when the water level drops.
What's really spooky is that Ed Kings' "Big Bang, No Theory" article appeared in the April 1995 Trains - only 2 or 3 months before this accident occurred.
Larry, Harvey, Carl, and others:
While reading in the DOT Library suplement area (ICC/DOT archives) I came across this accident involving a tank car of Nitromethane that suffered what seems to be a spontaneous explosion in MT. Pulaski, IL. June 1958.
Anyhow, I thought this might be a subject that you all might find of interest. (here is a small excerpt:
"...The explosion blasted a crater approximately 100 feet in diameter and 36 feet deep. The track structure in the immediate vicinity of the crater was destroyed. Cars standing on the main track, the New Storage Track, and the New Pass Track were blown from the tracks. Two cars stopped in the vicinity of the highway bridge and east of the tracks. Another car stopped approximately 300 feet south of the point of accident and 250 feet east of the tracks. The other derailed cars stopped within a radius of 250 feet of the point of accident. GATX 29633 and 17 other cars were destroyed. Twelve cars were heavily damaged by the explosion and some of these cars were further damaged by fire resulting from the explosion. Six other cars were somewhat damaged. The explosion scattered fragments of wreckage over a wide area. Considerable damage was caused to buildings in Mt. Pulaski by the fragments and by concussion. The highway bridge was damaged slightly
The conductor and the swing brakeman of the crew of No. 292 were killed, and the engineer, the fireman, the front brakeman, and the flagman were injured..."
Here is the link to the Report:
http://ntl1.specialcollection.net/scripts/ws.dll?websearch&site=dot_railroads
PNWRMNMThe Kingman incident is unique in that the car was not in transportation. It was spotted at the consignee's for unloading. For reasons that I don't think I ever knew one of the liquid lines came to discharge liquid LPG, probably Propane, and that discharge caught fire. This created the horizontal flame you see along the top of the tank. There are excess flow valves in the liquid and vapor lines that are intended to shut off the flow of product if the valve itself is sheared off, as in a derailment. The excess flow valve did not function in this case perhaps due to the flow resistance of the valve and pipe, perhaps the pipe was "necked down", or perhaps the liquid valve was less than fully open.
There was an article in July 1998 (if I remember correctly) issue of Firehouse. It has been a while since I read the article, but if I remember correctly, here is what happened. The fittings at the lines will sometimes come loose. The procedure when they do is to hit them with a brass tool (no sparks) to tighten them again. The crew unloading the car it the fitting with a steel tool, which caused sparks, with ignited the escaping LPG.
"No soup for you!" - Yev Kassem (from Seinfeld)
Paul_D_North_Jr For example, a tank of liquid carbon dioxide = CO2, or one of liquid nitrogen = N2 (apologies for the lack of proper subscripts, but I don't know if or how that can be done here).
Paul, I think you can do it if you compose your message in Word and copy it to the thread, but I know that if you compose it in WordPerfect, you can use subscripts, superscripts, accent marks, and all sorts of other goodies (I haven't tried Greek or Hebrew, but they may work, also) and copy them to the thread. CO2 H2O 24=16 Montréal 32o F. = 0o C. Such will involve a little more time, but then you will be more accurate in what you are writing.
No, it will not accept the Greek or Hebrew alphabets: áìåí ïîà.
Johnny
Paul,
Waverly was a delayed catastrophic failure of the tank caused by a combination of internal pressure and a cold work fracture on the inside of the tank due to a longitudinal dent to the tank shell. It is a longer, more complex story that I do not want to tell without having reference material in front of me. I also doubt that many here really care.
I disagree as to the causes of your "perfect storm". The most important factor was a series of changes to tank car construction that took place about 1960. They are; introduction of the specification 112/114 tank car, and increase in nominal capacity of tank cars from 50 ton to 100 tons.
Prior to the 112/114 specification, propane and several products with roughly equal boiling points and vapor pressure/temperature characteristics moved in specification 105 tank cars. For Propane these cars were about 12,000 gallon capacity. These cars featured a full length underframe. Most of them were insulated with cork blocks covered by a sheet metal jacket. They were 105A300W cars. The 300 is test pressure in pounds. Safety valve start to discharge pressure was 75% of tank test pressure, or 225 pounds. So long as the product had a vapor pressure of less than 225 pounds at 105 degrees F, it could generally go in such cars. There are a number of exceptions but the 105A300W cars were authorized for Propane, Butane, Vinyl Chloride Monomer, and Anyhdrous Ammonia.
The 112 specification was basically an UNinsulated 105. The upper 2/3 of the tank had to be painted white. Spec 114 was a 112 of noncircular tank cross section. Spec 114 cars were rare and I will use 112 to refer to both 112 and 114 from here on,
The direct comparison to the 105A300W was 112A340W. Note the increase in tank test pressure. The internal ambient temperature for checking vapor pressure was raised to 115 degrees as a result of removing the insulation. Also the safety valve start to discharge pressure was raised 10% from the standard 75% of tank test pressure to 87.5% of tank test pressure, or 280.5 pounds.
The first 112A cars were about 14,000 gallons on an underframe and 50 ton trucks. These were built in the late 1950's.
The carriers were under severe competitive pressure from alternate modes. The 100 ton truck was just coming into vogue, think "Big John" covered hopper cars. Someone got the idea to put 100 ton trucks under tank cars and to remove the dead weight of the underframe, both to increase carrying capacity per car. The result was 33,000 gallon 112A tank cars which were built by the thousands starting about 1960.
I will comment on your "perfect storm" below.
Paul_D_North_JrFinally, in retrospect I believe that in the late 1960's and the early 1970's there was a kind of 'perfect storm' of circumstances that caused this rash of tank car explosions and subsequent large number of deaths and other casualties loss among fire service and other emergency responders, railroad personnel, and nearby civilians. Those were - 1) poor track conditions that led to more frequent derailments, such as those on the L&N; 2) lack of protective devices on the tank cars themselves, such as the 'head shields' and perhaps some valving arrangements that you're more familiar with than me; 3) lack of haz-mat placards on the tank cars and other information - such as in the train manifests and MSDS sheets, etc. - to inform and warn the responders; 4) lack of 'blocking' and car placement rules that resulting in some very problematic proximities of different types of haz-mats to each other and risks during transport, such as shifted loads and rear-end collisions, etc.; and 5) lack of training and information among the responders and railroad personnel as to how the BLEVE-type failure and explosion could occur some time after the initial derailment, and is inherently different from some flammable material just exploding. As most of us know, a determined effort and expenditures by the railroads, shippers, and government over the next 2 decades or so addressed and greatly reduced or improved all of those circumstances so that they are much less common, though of course there's still more to be done, and ''It could still happen again''. That's 'the rest of the story'.
I am not sure I would agree to "large number" of casualties. When I was at the Bureau in Wasington DC in the late 1970's the railroads killed NO people most years compared to 30-40 for motor carriers. Both figures are all commodities.
1 There was certainly poor track and 100 ton cars found the weak spots, but this was not a tank car specific issue. I think the L&N had more than its share of memorable haz mat wrecks and I think they had an unusually high proportion of track related ones, but there was a lot of bad track back then.
2. The protective devices came along in the 1970's in response to the problems with 112 cars. Head shields, double shelf couplers, and thermal protection for flammable gas cars.
3. Cars transporting hazardous materials have carried placards since about 1908. Hazardous material were noted on consists, and travelled with waybills that described the contents by shipping name. The railroads and rail crews knew what they had.
4. Blockling rules are same today as they were then. The usual problem was blocks of flammable gas cars. Switching to break up and reassemble blocks of like cars imposes risk and greatly increases transportation costs. I am unaware of any serious push by anybody to make train makeup more complex than it already was/is.
5. This is true. It took a while for the railroads to figure out they had a problem and a lot, lot longer to convey the situation to the fire services.
More about the dent gauges are too much "inside baseball" for this venue.
Mac
I'd have to dig through a lot of (unsorted) copies of "Firehouse" magazine to find the story for more specifics, but...
Some years ago - early motorcar era - a natural gas liquification facility somewhere in the northeast suffered the catastrophic failure of a large insulated ball-shaped tank. The on-rushing LNG covered a fair distance, including entering storm drains, before it found an ignition source. Damage was significant.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Mac, thanks much for your comments and insights. They make a largely theoretical exercise in physics and Boyle's Law a lot more 'real' and interesting, and so easier to understand. Following are some comments and observations that your post has led me to. Please note that I'm not trying to 'hijack' the thread into a discussion of boiler explosions, but they have so much in common that I think they are a convenient point of departure for a discussion and analysis of this, as follows:
PNWRMNM [snip; emphasis added - PDN] The answer is that the horizontal flame is heating the tank shell in a location where it has no liquid in back of it. I always called this the teakettle effect. If you put a teakettle of water on the stove and turn the stove on as high as it will go after a while you get steam. This is the safety valve discharge. If you let the water all boil out, you will melt the teapot because the bare metal gets overheated and looses its tensile strength. At Kingman the tank fails at a pressure of about 300 PSI due the the tank shell near the flame becoming overheated and loosing its tensile strength. [snip] The liquid discharge from the punctured car(s) caught fire and the fire impinged on a nearby intact car(s). In the first part of the fire, the fire was impinging most directly on the bottom of the tank where there was liquid to absorb the heat. So far not much of a problem. The problem was some of the heat went high, into the vapor space. Worse, as the event continued, and as liquid was boiled to vapor and then discharged out the safety valve, the liquid level dropped which made more and more of the tank "bare", that is without liquid. At some point the tanks would fail due to flame impingement and loss of tensile strenth. I do not recall time to failure, but it was almost always long enough for the local responders to get there and expose themselves to a danger they did not understand.
[snip] The liquid discharge from the punctured car(s) caught fire and the fire impinged on a nearby intact car(s). In the first part of the fire, the fire was impinging most directly on the bottom of the tank where there was liquid to absorb the heat. So far not much of a problem. The problem was some of the heat went high, into the vapor space. Worse, as the event continued, and as liquid was boiled to vapor and then discharged out the safety valve, the liquid level dropped which made more and more of the tank "bare", that is without liquid. At some point the tanks would fail due to flame impingement and loss of tensile strenth. I do not recall time to failure, but it was almost always long enough for the local responders to get there and expose themselves to a danger they did not understand.
The portions emphasized by underlining above are common with locomotive boiler explosions. When the crownsheet goes dry due to low water level, it rapidly overheats, loses its strength, and collapses under the boiler pressure. A common example is if a cone-shaped paper cup ('Dixie cup') full of water is held with the outside over an open flame such as a chemistry lab Bunsen burner, the water will boil, but the cup won't burn - the heat is transferred to the water and released by boiling faster than the paper would reach its ignition temperature (or a melting or softening point in the case of steel). However, when and as the water is evaporated and the inside of the cup becomes dry, it will then start to char and burn. The best general explanation is of course this article in Trains -
PNWRMNM I never liked the term BLEVE since it did not address what was really going on which was loss of tank strength due to flame impingent on the vapor space.
I believe I see your point - breaking the event into 2 stages, neither of which is sufficient, and both of which are necessary - as follows:
1. Extreme heat on dry portion of tank ==> loss of tank strength ==> failure of confinement;
The fire/ heat usually does 2 things simultaneously - a) it heats the tank to cause the tank to fail; and, b) it heats the liquid inside, increasing the liquid's pressure and likely evaporating some of the liquid as you describe, which just exposes more of the tank as 'dry' and thereby aggravates the situation.
If there's no fire or heat, there's no pressure increase from that cause, nor accelerated evaporation of the liquid to expose more of the tank as 'dry'. But the tank could also fail 'cold' - from mechanical causes, such as impact and puncture during a derailment - almost instantly, then. See below for more on that.
And then,
2. Failure of confinement ==> loss of pressure ==> liquid transforms into gas phase ==> rapid expansion of the released liquid ==> explosive volume increase.
If the liquid doesn't undergo a huge increase in volume as it transforms into a gas, there won't be much of an explosion from that aspect - though there might well be if the liquid is flammable, of course. But this could also occur with a 'cold' rupture and leak - heat isn't necessary - it's the volume expansion as the phase changes from liquid to gas due to the loss of pressure that creates this explosive force. Otherwise, what that would be instead is a mere low-pressure gas leak and discharge (and maybe some liquid, too) from the ruptured tank. I'm not conversant enough with such materials to think of a good example that we could all relate to - maybe someone else can.
PNWRMNM I participated in circulating the story of Wavery in the railroad emergency response community and still have the Tank Car Dent Gauge that Bureau of Explosives inspector David B. Williams gave me the idea to create. The Bureau gave the gauge to all of its inspectors as did my railroad employer. When I was at Pueblo years ago we taught Waverly and use of the dent gauge. I do not know what they do at Pueblo now. Mac
I have not heard of the 'Tank Car Dent Gauge' before. Can we prevail upon you to explain a little more about it and its use ?
Finally, in retrospect I believe that in the late 1960's and the early 1970's there was a kind of 'perfect storm' of circumstances that caused this rash of tank car explosions and subsequent large number of deaths and other casualties loss among fire service and other emergency responders, railroad personnel, and nearby civilians. Those were - 1) poor track conditions that led to more frequent derailments, such as those on the L&N; 2) lack of protective devices on the tank cars themselves, such as the 'head shields' and perhaps some valving arrangements that you're more familiar with than me; 3) lack of haz-mat placards on the tank cars and other information - such as in the train manifests and MSDS sheets, etc. - to inform and warn the responders; 4) lack of 'blocking' and car placement rules that resulting in some very problematic proximities of different types of haz-mats to each other and risks during transport, such as shifted loads and rear-end collisions, etc.; and 5) lack of training and information among the responders and railroad personnel as to how the BLEVE-type failure and explosion could occur some time after the initial derailment, and is inherently different from some flammable material just exploding. As most of us know, a determined effort and expenditures by the railroads, shippers, and government over the next 2 decades or so addressed and greatly reduced or improved all of those circumstances so that they are much less common, though of course there's still more to be done, and ''It could still happen again''. That's 'the rest of the story'.
Comments and/ or critiques from anyone ?
P.S. - I take so long to type these up - in the meantime Larry gets in there first and posts much the same thing, only said better and with good examples, yet. So don't take the fact that my post showed up afterwards as contradicting either his or schlimm's in any way . . . Very good discussion, guys. Thanks ! - PDN.
Mac - On re-reading the account on Wikipedia, I'll have to agree with you that Waverly does not appear to meet the requirements of a BLEVE - especially since it appears there was no flame impingement at the time. Methinks it is very possible that some structural damage was sustained during the wreck (considering that the subject tank car was on the bottom of the heap) which resulted in a container failure, probably sudden, which lead to the explosion.
Based on what I've learned in hazmat classes, the tensile strength issue is pretty much at the heart of a BLEVE, as discussed. As I mentioned before, one portion of such a tank will often lay out flat - that would be the part which fails as the result of the flame impingement.
Another possible cause for a container failure would be purely mechanical - as in what often happens when 55 Gallon drums BLEVE, with one end or the other blown off.
This is likely what happened in Kansas City in the 1960's, when a fire at a tank farm resulted in the explosive failure of a horizonal bulk tank (gasoline or fuel oil). The tank remained pretty much in place, but the contents were ejected - toward the street and the firefighters who were trying to deal with the inferno. Five died.
BLEVE's are not limited to the rails. They can, and do, happen with fixed facilities and highway vehicles.
The thing with the 500 GPM - Given the water supply, I can easily put that much water on the point of flame impingement. In most areas, however, getting that much water available will take considerably longer than the 10 minutes or so at which point a BLEVE starts to become a real possibility. In other words, if I know the incident is going to take place, and where, I'll get set up for it now....
Firefighters tend to be a highly motivated lot, who want to get in there and make the fire go away. Sometimes you gotta protect them from themselves.
Paul_D_North_JrA locomotive boiler explosion is a BLEVE with a container of water . . . - Paul North.
A locomotive boiler explosion is a BLEVE with a container of water . . .
Or mixture of water and steam. Ever see footage of a P-47 strafing German steam locomotives in the war? A tremendous blast just from the penetration of the boiler shell by one or more 50 cal. bullets.
C&NW, CA&E, MILW, CGW and IC fan
ericsp A BLEVE does not need to involve a flammable liquid as the boiling liquid (although probably most do). You can have a BLEVE with a container of water.
I was thinking about that this morning, too. For example, a tank of liquid carbon dioxide = CO2, or one of liquid nitrogen = N2 (apologies for the lack of proper subscripts, but I don't know if or how that can be done here). Both are essentially inert - the CO2 is also a fire extinguishing agent - but the BLEVE's sudden expansion effect could occur just the same, only without the fire and any additional explosive effects from the very rapid combustion and that resulting expansion.
tree68HarveyK400I think it was in Gibson City, IL where a bleve following a derailment destroyed much of the small town in late 60s or early 70s. Couldn't find it on Google. I'm pretty sure it was Gibson City which suffered a catastrophe at a fuel supplier which was caused when the engine of a truck delivering fuel oversped and caused a fire that involved their warehouse and bulk storage tanks. I was at Chanute AFB and heard about it when I heard that Chanute (at the time home of the USAF firefighting school) had sent a crash truck there. It was out when I got there, but not by much. Edit - this would have been in 1974, so the time frame is right... Despite the significant rail presence in town, I don't believe any railroad equipment was involved. Paul - thanks for expanding on my post. I saw an account of a firefighter who was caught within a BLEVE. He escaped the physical portion of the explosion unharmed, but was within the fireball. He said it looked like it was raining fire. Fortunately, he suffered no major injuries. Sam - Thanks for the link. Waverly definitely qualifies for inclusion in my initial list.
HarveyK400I think it was in Gibson City, IL where a bleve following a derailment destroyed much of the small town in late 60s or early 70s. Couldn't find it on Google.
I'm pretty sure it was Gibson City which suffered a catastrophe at a fuel supplier which was caused when the engine of a truck delivering fuel oversped and caused a fire that involved their warehouse and bulk storage tanks.
I was at Chanute AFB and heard about it when I heard that Chanute (at the time home of the USAF firefighting school) had sent a crash truck there. It was out when I got there, but not by much.
Edit - this would have been in 1974, so the time frame is right...
Despite the significant rail presence in town, I don't believe any railroad equipment was involved.
Paul - thanks for expanding on my post.
I saw an account of a firefighter who was caught within a BLEVE. He escaped the physical portion of the explosion unharmed, but was within the fireball. He said it looked like it was raining fire. Fortunately, he suffered no major injuries.
Sam - Thanks for the link. Waverly definitely qualifies for inclusion in my initial list.
1974 was also the year of the horrible N&W explosion in Decatur, Illinois
Mac, thanks for sharing.
I hadn't heard the role of tensile strength failure in these explosions; but it has a parallel in architecture. An Underwriter's Laboratory film showed the effect of an open fire on loaded timber and steel beams. Although burning on the outside, the wood retained most of its structural integrity while the steel lost its strength and deformed first, causing the supported floor to collapse.
Harvey
I was five years with the Bureau of Explosives and eight (1974-1988 total) in the Hazardous Material Control operation of a Class I rail carrier that handled a lot of hazardous materials.
The Kingman incident is unique in that the car was not in transportation. It was spotted at the consignee's for unloading. For reasons that I don't think I ever knew one of the liquid lines came to discharge liquid LPG, probably Propane, and that discharge caught fire. This created the horizontal flame you see along the top of the tank. There are excess flow valves in the liquid and vapor lines that are intended to shut off the flow of product if the valve itself is sheared off, as in a derailment. The excess flow valve did not function in this case perhaps due to the flow resistance of the valve and pipe, perhaps the pipe was "necked down", or perhaps the liquid valve was less than fully open.
The flame shooting straight up is the safety valve discharge. The safety valve of a 112A340W car, the most likely at the time, starts to discharge at 280.5 pounds per square inch. If you have no SV discharge, the internal pressure is less than 280#, if you have SV discharge you have more than 280#. The safety valve is designed to hold a pressure not to exceed about 306 pounds. I say "about" because my books are in boxes so I can not quote to the pound. The tank has a design burst pressure of 850 pounds. The $64,000 question is why did the tank fail?
The answer is that the horizontal flame is heating the tank shell in a location where it has no liquid in back of it. I always called this the teakettle effect. If you put a teakettle of water on the stove and turn the stove on as high as it will go after a while you get steam. This is the safety valve discharge. If you let the water all boil out, you will melt the teapot because the bare metal gets overheated and looses its tensile strength. At Kingman the tank fails at a pressure of about 300 PSI due the the tank shell near the flame becoming overheated and loosing its tensile strength.
Someone in the fire service invented the term BLEVE to describe Kingman and/or the series of accidents including Crescent City and Onienta. Film from Crescent City was widely shown. We had a copy and showed it to on line Fire Departments. All of these accidents involved multiple 112A/114A tank cars moving in a block. The train derailed and one or more cars was punctured low on the tank. The liquid discharge from the punctured car(s) caught fire and the fire impinged on a nearby intact car(s). In the first part of the fire, the fire was impinging most directly on the bottom of the tank where there was liquid to absorb the heat. So far not much of a problem. The problem was some of the heat went high, into the vapor space. Worse, as the event continued, and as liquid was boiled to vapor and then discharged out the safety valve, the liquid level dropped which made more and more of the tank "bare", that is without liquid. At some point the tanks would fail due to flame impingement and loss of tensile strenth. I do not recall time to failure, but it was almost always long enough for the local responders to get there and expose themselves to a danger they did not understand.
I never liked the term BLEVE since it did not address what was really going on which was loss of tank strength due to flame impingent on the vapor space. Some time in the 1970's a Fire Service author wrote an article that said in essense not to try to fight the fire UNLESS you could get 500 gallons of water per minute on the point of flame impingement. When I asked him the basis for the 500 gallons, expecting a discertation on BTUs from the fire, the heat absorption capability of water, the effectiveness of water delivery systems, the answer I got was "No one can pump that much water". My faith in fire service authors fell a bit that day.
Waverly was an entirely different type of accident which in the interest of time I will not discuss in detail. The Wikaedia article contains the kernal of truth, but as typical of the fire service attaches the term BLEVE to this case as well. After Waverly I became more critical of the term BLEVE, since applying it to the facts of Wavery could only cause confusion. Some of the fire guys got my point, others told me to shut up, Waverly met the fire service definition of BLEVE and who was I, a mere railroader to tell them any different or criticise there use of their word. Fortunately for them there has not been another Waverly disaster.
I participated in circulating the story of Wavery in the railroad emergency response community and still have the Tank Car Dent Gauge that Bureau of Explosives inspector David B. Williams gave me the idea to create. The Bureau gave the gauge to all of its inspectors as did my railroad employer. When I was at Pueblo years ago we taught Waverly and use of the dent gauge. I do not know what they do at Pueblo now.
A BLEVE does not need to involve a flammable liquid as the boiling liquid (although probably most do). You can have a BLEVE with a container of water.
What makes the BLEVE worse than a boiler explosion is the ignition of the expanding gases. The resultant fire ball covers a much larger area and usually results in igniting more fires than does a boiler explosion.
Mike Ball
Thanks for jogging the gray cells. I remember the TP&W was involved; so that fits.
I've seen some films too. Used to represent the regional commission for disaster response planning, facilitated planning for an exercise, and was the transportation chairperson for the county Red Cross chapter. One thing I learned was never go anywhere near a smoke or vapor cloud - like in miles.
CShaveRRHarvey, you might be thinking of Crescent City, on the TP&W. I seem to remember seeing a training video featuring that tank car at Kingman. I think they knew that it was going to blow, but had no idea how bad it was going to be. I recall being told that the men seen working around the car before the explosion were killed.
.
Carl
Railroader Emeritus (practiced railroading for 46 years--and in 2010 I finally got it right!)
CAACSCOCOM--I don't want to behave improperly, so I just won't behave at all. (SM)
I think it was in Gibson City, IL where a bleve following a derailment destroyed much of the small town in late 60s or early 70s. Couldn't find it on Google.
....That Kingman, Az explosion caught my eye......Know just about where that incident took place....Old 66 near by.
I happened to have worked on auto testing work out of that town some years ago and a short time before that happened.
tree68 [snip] Those explosions are known as BLEVE's (blev-vee). It stands for Boiling Liquid Expanding Vapor Explosion. Simply put, if/when fire impinges on a container it causes the liquid inside to heat up, even boil, and of course, expand. Secondly, that same fire combines with the pressure to weaken the container and eventually it fails. With tank cars, the failure often involves one end of the car laying out flat. The other end, still more or less intact, but no longer attached, is still full of liquid - you now have a rocket if the contents are flammable. That can propel the intact end upwards of half a mile. This is why authorities evacuate for great distances around such incidents. I've seen video of the Oneonta incident. People were walking around like they would if a building were on fire. It was this incident that caused one hazmat type to coin the phrase "Go to the top of a hill and watch, 'cause you'll never see anything like it again, and you're not going to do anything about it..."
With tank cars, the failure often involves one end of the car laying out flat. The other end, still more or less intact, but no longer attached, is still full of liquid - you now have a rocket if the contents are flammable. That can propel the intact end upwards of half a mile.
This is why authorities evacuate for great distances around such incidents.
I've seen video of the Oneonta incident. People were walking around like they would if a building were on fire. It was this incident that caused one hazmat type to coin the phrase "Go to the top of a hill and watch, 'cause you'll never see anything like it again, and you're not going to do anything about it..."
A BLEVE is just like a boiler explosion, only by another name and more general. To add/ insert a little bit to Larry's sequence - "if/when fire impinges on a container it causes the liquid inside to heat up, even boil, and of course, expand", the real dangerous part happens just after the liquid inside heats up and wants to boil - but can't, because it is confined in the tank and hence under pressure, but that pressure gradually increases as the heat is added. Then when the tank or vessel eventually fails, the confinement disappears, and the liquid is free to expand. Since the volume of most liquids expands to many times greater when they turn into a gas - it's something like 1,400 times bigger for steam than water, IIRC - the liquid 'flashes' explosively into a gas with a commensurate EDIT: pressure volume increase, and that's what really provides the force that launches the tanks into a sub-orbital trajectory.
A college friend who worked for the D&H at the time of the Oneonta wreck performed the surveying to measure the locations of the tank car wreckage, and to rebuild the main line. Between the wreck and the blast, a considerable distance of the 'sidehill' roadbed was destroyed, and had to be rebuilt with a considerable amount of earthwork, in the dead of winter. It took several weeks, as I recall.
tree68 Kingman, Crescent City, and Oneonta (and some others) changed how the fire service views tank car fires. No one really realized that part of a railroad tank car can travel over half a mile as the result of such an explosion. Those explosions are known as BLEVE's (blev-vee). It stands for Boiling Liquid Expanding Vapor Explosion. Simply put, if/when fire impinges on a container it causes the liquid inside to heat up, even boil, and of course, expand. Secondly, that same fire combines with the pressure to weaken the container and eventually it fails. "...With tank cars, the failure often involves one end of the car laying out flat. The other end, still more or less intact, but no longer attached, is still full of liquid - you now have a rocket if the contents are flammable. That can propel the intact end upwards of half a mile. This is why authorities evacuate for great distances around such incidents. I've seen video of the Oneonta incident. People were walking around like they would if a building were on fire. It was this incident that caused one hazmat type to coin the phrase "Go to the top of a hill and watch, 'cause you'll never see anything like it again, and you're not going to do anything about it..."
Kingman, Crescent City, and Oneonta (and some others) changed how the fire service views tank car fires.
No one really realized that part of a railroad tank car can travel over half a mile as the result of such an explosion.
Those explosions are known as BLEVE's (blev-vee). It stands for Boiling Liquid Expanding Vapor Explosion. Simply put, if/when fire impinges on a container it causes the liquid inside to heat up, even boil, and of course, expand. Secondly, that same fire combines with the pressure to weaken the container and eventually it fails.
"...With tank cars, the failure often involves one end of the car laying out flat. The other end, still more or less intact, but no longer attached, is still full of liquid - you now have a rocket if the contents are flammable. That can propel the intact end upwards of half a mile.
Larry;
Your last two paragraphs are very prophetic, and to the poit of current techniques for handling tanker (rail ro otherwise) fires or their potentials.
Don't know if you recall an incident in 1978 on the L&N RR at wqaverly,Tennessee, but it involved a train wreck in which a 2,000 LPG tanker was wrecked along with an number of other cars in the commercial section of town. It was a horror when it exploded, there were eleven individuals killed in the explosion. Those killed were 'experts' in the fire service and emergency services, as well as railroad wreck clean-up personnel. Parts of the tanker were hrown several hundred feet from point of detonation. There were over 125 people(+,-) evaced to hopsitals as far away as Memphis (about 150 mi away). It too lead to a re-examination of the way's to respond to a potential situation involving large quantities of liquified gases in trucks or rail tankers.
(edit) Found the following link and a good descrription to the Waverly Train Wreck:
http://en.wikipedia.org/wiki/Waverly,_Tennessee_tank_car_explosion
Thought you might find this of interest.
Here are some frighting pictures. The explosion killed 13 people. I think the dark spot a bit above and slightly to the left of the F in the second picture is part of the tankcar.
http://www.firehistory.org/images/front_07-05-2008_kingman-1.jpg
http://www.firehistory.org/images/front_07-05-2008_kingman-2.jpg
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