Why create and use chemicals that become volatile/dangerous/deadly when not kept cool? Electricity goes out, KABOOM?

With electricity out in Texas due to Harvey a chemical plant can do nothing but wait for the explosions and concomitant fires. There are 8 structures or were and I think two have already exploded due to the heat. The drift will be contaminated of course. Thank you for your reply Malizz and Happy Friday.

Seriously?

Other way round. Flood kills electrics, out go lights. Try backup electric, gone as well. Too late to move chemicals which warm up and KABOOM KABOOM. 

But gasoline can be stored without air conditioning. 

If a car overheats it will explode? I did not know that. I am specifically referring to the situation in Texas with that chemical company. The chemicals are exploding and the structures catching on fire because they need to be kept at a specific temperature. With electricity out there is nothing they can do but wait for the explosions and fires. There were eight or structures and I believe several have already exploded. They had folks within a 1-1/2 mile radius leave their homes because of that. They sit by watching and waiting. What the  chemical drift will do to the air and health of the folks there I don't know. Thank you for your reply.

 I'm not sure I understand the answer Durdle. Thank you for your reply and Happy Saturday! :)

These chemicals are either intended to be volatile and combustible - i.e. fuels - or are that by their nature, but are necessary in making all manner of materials that may or may not be particularly hazardous, but which we rely on in daily life, such as plastics, paints, adhesives and so on.

What I don't understand is why the structures containing these volatile fluids exploded - it suggests they were not designed to cope with the plant shutting down in an unplanned manner. Nor do I know how they "exploded" - simple bursting by over-pressure, or some form of ignition. If a tank holds only a volatile substance combustible in both liquid and vapour form, mere overheating in the sun will not cause the fluid to ignite.  It can only do that if oxygen is also present in appropriate quantities. If the tank were to burst by over-pressure, then the vapour could indeed burn but only if something ignites it; possibly explosively with a risk of rupturing the plant and literally adding fuel to the flames.

For such an uncontrolled burst, the tank and/or pipes and fittings would have to be too weak to hold the fluid at its new pressure; and, just as importantly, it has no relief valves that would release some of the fluid in a controlled, reasonably safe manner. 

The problem then is NOT why do we have these hazardous materials.

It is whether the systems made for processing and storing them are made to fail safely - why an unplanned loss of cooling system leads to a situation dangerous because the processing plant itself cannot respond appropriately.

 Essentially, the fault lies with those who failed to consider all eventualities and consequences despite the wealth of experience available to help them do so. Look at other major industrial disasters...

The Tay Bridge Disaster. The bridge used metals good for their usual purposes but not for big structures; and then only if used properly. Here they were the wrong choice, the design failed to consider wind-loads, and the workmanship in building the bridge was very poor indeed. Remedy? Use appropriate materials, proper quality-control and supervision; and learn how bridges actually "work" before designing them.

A litany of collisions on the early railways. Why? Flawed signalling systems operated by sometimes-inexpert staff under pressure, in a system still in its infancy. Remedy from tragic experience - not always entirely fool-proof but far, far better than previous practice? Interlocked points and signals - something apparently missing from German railways judging by that collision on a single-track line a year or so ago.

The Titanic. The ship was built above contemporary standards, but there was not yet the experience to consider all possibilities, like a rupture of several water-tight compartments at once - but we cannot expect the builders to think of reckless ship-handling in hazardous waters, given the regulations etc. governing maritime skills. The latter echoed a few years ago by the Costa Concordia disaster despite even more regulations.

Three Mile Island reactor failure. The control desks were mirror-imaged for aesthetics not function, so when something went wrong, the operators were confused into making serious mistakes in the stress of the moment. Yet similar nuclear power-plants were already in operation elsewhere around the world, in as near safe conditions as can be obtained; so the cause was NOT "nuclear power" but irrational human error (in the layout, made in calm conditions) compounding understandable human error (under great stress).

Fukushima: nothing at all wrong with the plant. The safety systems all operated properly - or would have done if someone had thought better of placing the emergency generators next to, and only just above, the sea in a region prone to tsunamis. 'Tsunami' is the Japanese word for them, after all.

Always look beyond the obvious! Very often, it is not the thing or stuff that is the problem, but people not fully appreciating its behaviour and its surroundings.

Hi Durdle. My understanding is that the chemicals had to be kept cool. Isn't the same true of nuclear material? Now why they had to be kept cool to remain stable I do not know but it seems like playing Russian Roulette if you have to rely on electricity to do the cool-keeping. It can always go out but why wouldn't they have backup generators that would automatically kick in? You say to always look beyond the obvious. That only works if you are knowledgeable enough about a subject and know what lies  beneath it or above it or around it. It doesn't work if all you have is what you are told with nothing further given. When I read that something is going to explode if it gets too hot I believe it. I stop right there and wonder WHY? Thank you for your thoughtful and informative reply as always and Happy Sunday! :)

You are right- nuclear material has to be kept cool because the fission produces heat, though as far as I understand it, the heat does not increase the rate of fission. It breaks the containment vessel instead if it increases excessively in quantity and temperature.

The problem is not whether you or I understand engineering. Nor even if politician and journalists do - most don't! That understanding is the responsibility of the plant designers and users. They should also understand hazard, probability and risk - three very different things many members of the public, journalists and politicians seem not to realise or understand. 

These things are known to plant and process designers and operators, but many cases of disastrous failure can be attributed to them not thinking far enough about risks, hazards and consequences even when the science and engineering principles themselves are familiar through accumulated experience and learning.

However, many accidents have occurred even when the thinking was as far as could be expected; by simple mistakes, in some cases very small ones that triggered a chain of events and co-incidences leading to catastrophe.

Humans do err, it's natural and should not treated as a crime; but the idea should be that the engineering itself, or those operating it, spot the error in time and respond appropriately so it cannot lead to an accident.

In the German railway accident I cited, I wondered if the line did not have fully-interlocked points and signals. They would have signalled the driver to stay put at the station - like traffic-lights. Instead it appears someone sent the poor driver off with his train onto an occupied line - so they prosecuted the someone as the easy way out. Though found negligent anyway, its own hazard, the real failure was not his but at top level in not ensuring basic engineering (the interlocking) to minimise the risk of such negligence or mistake causing an accident. The driver might have ignored the red light but it's pretty unlikely. This principle was established in the 19C for Heaven's sake!

The breakdown of the nuclear power-plant at Fukushima was due to failures of both main and emergency electricity supplies - the reactors were not damaged by the tidal wave and had shut down as they should but you can't turn off a reactor like you can turn off a diesel engine. Their fuel would still have been undergoing fission so still producing heat, albeit at a lower rate than in full production. The fundamental flaw was in placing the stand-by generators etc within possible reach of a large tsunami. Had they been out of reach, and the equipment around the reactors been able to withstand inundation by salt water, the system may well have coped.

To return the analogy to Texas, given that the area can be affected by major storms, then surely the fundamental problem is not that posed in Rosie's original question - why do we need hazardous chemicals - but instead, is why did the plant designers not ensure it as a whole can cope with power-cuts as well as direct weather damage.  

The early disaster I described - Tay Bridge - could be put down to inexperience. Building large, heavy viaducts across wide estuaries was still a new branch of civil-engineering. The Titanic too, taught that we can't always plan for all eventualities because we are not sooth-sayers and not everything is reasonably predictable (ask an Italian seismologist); but we can plan as far as our collective experience to that point allows.


Nowadays , professional engineers have a collective, world-wide, two centuries' worth of experience, a lot of it tragic. Things will still go wrong. Of course they will, but that wealth of experience should allow the hazards to be known or foreseen to a point, their risks established and the appropriate precautions taken to allow the events or processes to function as safely as possible.

And that is the task of the Engineer, supported by the Scientist - the rest of us can only expect them to act correctly, with the proviso, "as far as reasonably practicable" - to use the term from work-place health & safety law.

Don't blame the event, product or process; blame humans for not learning from past errors in handling them.  

Thank you for another thorough and informative analysis Durdle. "...them thinking not far enough about risks, hazards and consequences".  What is "far enough"? In QC/QA departments who decides what tests are necessary and how many over how long a period of time is required to insure product safety BEFORE a product is released to the public? A question I'm gonna ask. There are constant recalls so the system they are using isn't working. What would? This post was edited by RosieG at September 12, 2017 3:43 AM MDT

No human-made system or endeavour can ever be 100% safe or reliable.

Design, QA and Safety departments do their best but as I say, no-one can foretell the future.

The problem I see is not that, but of failing to take past accumulated experience and where applicable, local knowledge, into sufficient account.  Of the incidents I detailed, the railway collision suggests lack of applying long-established safety practices, while the Fukushima disaster suggests no-one considered that tsunami heights cannot be forecast.  

Recalls do not show the system is failing. The opposite actually!

The failure would be if the product is not recalled when it proves unreliable or unsafe. Design and manufacturing tests endeavour to sift out the weaknesses at the start, but they cannot be expected to pick up every last weakness that does not show until the item has been in service for a while. This is more likely when the part that fails is not made by the end-manufacturer.

There is an old adage, that 'The man who has never made a mistake, has never made anything'. The ideal is that the mistake teaches what needs to be improved or changed. 

What do you think about the manufacturers who KNOW their products are defective but cover it up and sell them anyway? They lie. One auto company (I forget if it was Honda or Toyota or another one) LIED about mileage..mpg. I think another one LIED about emissions standards. I don't know whether  Taka or Tanaka or whomever knowingly put out airbags that were defective but I wouldn't doubt it. I KNOW cigarette company executives LIED about the harm cigarettes can do to the human body. I have read about baby food juices being watered down. I doubt that would kill a baby but it certainly is cheating and depriving the child of 100% nutrition. I don't know for sure if  pharmaceutical companies or end users have ever watered down chemo drugs but I've seen movies where that happened and I wouldn't doubt it. Truth in advertising is a joke. Caveat emptor is more likely the truth we should all accept. How do you KNOW whom you can trust when you buy anything? It seems greed is the driver in every business and short cuts save money so they use them. I think some companies gamble that the cost of lawsuits will be less than the cost of making a better product. They get away with whatever they can and weigh the odds of getting caught. SIGH. Thank you for your reply Durdle. Woe is us! :(

Ah, well, deliberate concealment of known defects or effects amounts to fraud, or in UK law, Selling Goods Not Fit For Purpose. That is a very different matter from honest mistakes or events genuinely not being foreseeable - and is totally wrong!

One of the reasons behind the EU's CE-labelling laws, apart from trade-protectionism, may be to try to avoid such fraud. Whether it works in every case is another matter, but under it, samples of each new product have to undergo stringent tests in independent laboratories before being authorised for sale. The indication to the buyer that it is so authorised is the CE mark, and with comes a raft of paper-work full of references to this-that-or-the-other official standards, genuine legalese and bizarre EU jargon. 

This system may not catch everyone, including the makers of fake goods (the CE documents even give a helpful diagram of the logo so you can make an exact copy), but it does help identify counterfeit products, and in investigating genuine manufacturers found to be passing off unfit ones.

But expensive. Electrical cooling is cheaper.
Like the Fukushima designers who failed to build the seawall high enough for a "once in a lifetime" tsunami event, likewise the designers of the Houston plant didn't take hurricanes into account. Storm surges took out the backup generator (which should have been on the roof - putting it on the ground makes it much easier to fuel but leaves it vulnerable to flooding) and the cooling system died.

First of all no, absorption-type chillers are not more expensive, they're actually less expensive to operate. In fact, I know of a number of buildings in NYC that use absorption chiller systems of the lithium bromide exchange type because the operating costs are considerably lower than mechanical compression type chillers. The can even work from directly-collected solar energy. There's even gas-fired versions of mechanical compression chillers available too. (I do note that smaller refrigeration systems like the typical kitchen food refrigerator and gas fired AC chillers and heat pumps in the 5-ton range use the ammonia exchange principle.) The only problem is that the servicing technicians actually have to have a brain. And this solution for the chemical plant was suggested as a much simpler "mission critical" back-up to the main cooling system; a lot fewer parts to fail.

Had the Fukushima nuclear plant been retired at the end of its design life the accident wouldn't have happened. But it was pushed beyond that date by 20+ years. And then there's the fact that it was still making power but lost incoming mains which took out the control and cooling systems. The damned plant was designed to only obtain operating power from the electric grid! Plants in the US have the capability to run off the power that they actually generate as well as power from the electric grid and from their own stand-by gensets. What a novel concept. And yes, the standby generators in Japan should have been mounted up high, not "in the basement". 

Supplying fuel to elevated gensets is not an issue either, done all the time in the States. There are a lot of stand-by gensets around the US that are roof-top mounted. I'm familiar with such installations in NYC, DC and Chicago. The spark-ignited ones run on natural gas that's delivered directly to them at "distribution" pressure and then regulated down to the required equivalent water pressure at the prime mover. The diesel units have pumps adjacent to their main basement storage tanks that fill "day" tanks that are located in close proximity to the genset many stories above. Much easier than dealing with the condenser water in a basement-located chiller system with an open, rooftop-mounted cooling tower.