Wikipedia:Reference desk/Archives/Science/2014 June 16

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June 16

Chemical leak

What's the safest way to stop a leak of concentrated sulfuric acid from a ruptured tanker truck? Thanks in advance! 24.5.122.13 (talk) 03:05, 16 June 2014 (UTC)

Although this question isn't specified as one that is not allowed (see top of page), any question that giving the wrong answer could result in dead people should not be answered here!  =8^O  :71.20.250.51 (talk) 03:27, 16 June 2014 (UTC)

Ya know, if the emergency responders are looking this up on Wikipedia, I think there is some risk of death in any circumstance. Wnt (talk) 04:41, 16 June 2014 (UTC)

The problem is people giving their own opinions, there is no problem referring to authorative sources or to a Wikipedia article on the subject is the query is straightforward to interpret. Dmcq (talk) 13:15, 16 June 2014 (UTC)

Not technical advice -- this is for novel research (see my earlier Q's about hazmat cleanup, avalanche debris, etc.) 24.5.122.13 (talk) 07:42, 16 June 2014 (UTC)

Perhaps some sort of carbohydrate foam, gel or paste that that can be sprayed or slathered on? The dehydrating ability of concentrated sulfuric acid should carbonize the foam, gel or paste, creating a water-tight, acid-resistant seal that should last long enough for the tank to be emptied. In theory, a very sweet dense meringue could work. Plasmic Physics (talk) 04:02, 16 June 2014 (UTC)

Maybe epoxy resin would work? I'm thinking either that, or weld the rupture shut. 24.5.122.13 (talk) 07:48, 16 June 2014 (UTC)

How does epoxy resin behave under the circumstances? Welding temperatures will produce toxic sulfur oxides, not sure that is such a practical idea, considering the precautions necessary. Plasmic Physics (talk) 11:31, 16 June 2014 (UTC)

I forgot, sulfuric acid vapour is virtually just as toxic as sulfur oxides, so precautions are needed in either case. However, I don't think that welding is a relatively safe option. Plasmic Physics (talk) 13:07, 16 June 2014 (UTC)

Epoxy will self-polymerize on contact with any sort of acid. As for welding, I agree that it can be dangerous. So epoxy it will be in my scenario. 24.5.122.13 (talk) 22:52, 16 June 2014 (UTC)

First step is to list some incidents to see if there's a state of the art. Searching "sulfuric acid" "tanker truck" "leak" I see lots of stuff like May 8 in Carson Feb 10 in Tulsa Frederick in 1994 Sullivan in 2011 McCool ... it's clear that anyone with a genuine occupational need can get on the horn and quiz them about their procedures. But there should also be publications... Wnt (talk) 04:48, 16 June 2014 (UTC)

These are small-scale leaks -- I'm thinking something much bigger. The scenario I have in mind is, the truck gets swept off the road and down an incline by an avalanche, hits an aboveground gas pipeline with its downhill end (thus rupturing and igniting it at once), and comes to rest against the now-blazing pipeline with a rupture at the lowest point of the tank. (This is an UGLY scenario -- you have not only a major acid spill, but a gas fire in immediate proximity, which in turn causes large quantities of acid aerosol to spread downwind.) Also in this scenario, the tank will partly melt from the heat, greatly exacerbating the leak and creating the risk of a BLEVE. First order of business in this case is to shut off the gas; but with the tank partly melted and leaking fast, what can be done to stop the leak? 24.5.122.13 (talk) 07:58, 16 June 2014 (UTC)

In real life, you would (1) evacuate everybody for several miles around, especially downwind; (2) shut off the pipeline; (3) wait until an airborne tanker can safely fly overhead; (4) dump fire retardant to put out the fire; (5) probably dump a bunch of sodium bicarbonate (baking soda) to neutralize the acid. No human is going to be allowed near that while there is a big fire and a big acid leak. Looie496 (talk) 12:39, 16 June 2014 (UTC)

Dumping baking soda or any other neutralizing agent will cause an exothermic reaction that will create MORE acid aerosol. An adsorbent (like cat litter) would be a better choice -- once the leak is stopped somehow and the spill contained! 24.5.122.13 (talk) 22:52, 16 June 2014 (UTC)

Details of some real acid leaks can be seen here at the aptly named sulphuric-acid.com. Alansplodge (talk) 12:43, 16 June 2014 (UTC)

I don't have the time to read through the entire link, but thus far, I'm yet to find a single example describing the method used to seal a rupture. There is an abundance of examples stating the occurrence of a sealing, but no actual description. Plasmic Physics (talk) 12:59, 16 June 2014 (UTC)

Really, do you then suppose that it is acceptable to let the entire tanker empty out naturally, and tend to the resulting mess afterwards? Plasmic Physics (talk) 12:59, 16 June 2014 (UTC)

That is probably what would be done. Unless the leak is only an inch or so in diameter, it's going to drain in a matter of minutes. Chances are the first responders don't have anything that wouldn't be on a typical fire trucks. Their tools are generally designed to make holes bigger, not smaller. I doubt they would even have a welder on hand. They certainly wouldn't have time to go out and get some epoxy resin or something. They would presumably go by the book. For a gas pipeline incident, the instructions are to not attempt to extinguish the fire, evacuate the area, move upwind, and contact the pipeline operator to shut it off. For fires involving corrosive, water-reactive liquids (like sulfuric acid), recommendations are to consider evacuating a half mile in all directions. Once the pipeline is shut off, if there is still a fire and the acid is still leaking, then large amounts of water would be used to keep the tank cool. Mr.Z-man 15:21, 16 June 2014 (UTC)

That's a good plan, except for one little thing: In my scenario, there will be people who will need some help evacuating the area -- the trucker, who's been ejected from the cab straight into the pool of acid; a mother and daughter, both badly wounded and trapped in a wrecked car dangerously close to both the pipeline and the truck; and several skiers caught in the avalanche and carried across the road into the acid pool. I believe the rescue team should try to get them away from the area as soon as the gas fire is out, and before dealing with the acid spill, even though it may mean taking their chances with the aerosol? 24.5.122.13 (talk) 23:11, 16 June 2014 (UTC)

That assumes any of them actually survive the fire. Natural gas can burn really hot. If it's hot enough to partially melt the truck, it's hot enough to cause serious burns to people nearby, in addition to the chemical burns, toxic gases they're inhaling, and physical injuries from the accident itself. The MSDS recommends a water spray to manage vapors. That plus a SCBA system would probably be enough for anyone not lying in a pool of acid. For that they'd need full chemical suits. But those people are probably dead, because lying in a pool of boiling-hot acid is not something people would likely survive. Water over 69 C can cause third-degree burns with 1 second of contact. Mr.Z-man 03:44, 17 June 2014 (UTC)

With luck, one can survive third-degree burns to even 80% of his/her skin area. But yes, inhalation of acid vapors will significantly worsen prognosis, as will the blunt trauma from the avalanche itself. I'm rethinking the acid immersion -- maybe only the trucker will be immersed (and will die in surgery), but the skiers will be outside the acid spill but inside the toxic vapor cloud? 24.5.122.13 (talk) 07:35, 17 June 2014 (UTC)

Called to this likely scenario for a 1970s Disaster film the local police chief realizes the only man who can save the little girl trapped in the tanker is Bamro, a Vietnam veteran who has retreated to a Shaolin Monastery in search of absolution as he is haunted by flashbacks to the burning of a village. By the 3rd reel, Bamro is racing to the scene in his Shelby Mustang pursued by black helicopters (firing RPGs inaccurately) sent by agents of the Venusian mafia intent on accelerating acid rain on Earth until its atmosphere matches their own sulphuric acid atmosphere, preparatory to an invasion of Earth by Venus. Bamro arrives at the disaster scene where the police and firemen take cover from the helicopters that continue to fire (inaccurately) on everyone. The police chief has found out that the "accident" was caused deliberately by Venusians but his calls for air force help are ignored because the helicopters are invisible to radar. Bamro alone risks the fire and shooting to climb into the truck. Seeing the little girl provokes a flashback to when he failed to save a girl in the burning village in Vietnam. The truck's fuel tank explodes, trapping them both in the blazing truck. Outside cowering with the police chief we see an Asian lady collapse in tears, she is the girl's mother. Inside the truck, Bamro releases the red-hot parking brake and the truck begins to roll away from the pipeline, gathers speed and plows into a snowdrift at the bottom of the incline. In the closing scene it is evening, the snow is lit by red and blue flashing lights as rescuers dig out badly burned Bamro (he'll live) and the unharmed little girl, both welcomed by the mother whom Bamro recognizes as the girl he thought died in the village. The little girl asks "Are you my daddy?". 84.209.89.214 (talk) 14:07, 16 June 2014 (UTC)

Hmmm, I saw that movie. (spoiler alert!) I think you skipped over the part where the insurance company lawyer insists (against all advice) that the fire truck try to put out the burning truck with a water hose - and performs a perfect Wilhelm scream as he's dissolved down to a skeleton by the resulting spray of boiling acid. I did like the part in the closing scene where Bamro insists on plunging his scorched hand (a rare case of fifth degree burns!) back into the snowdrift to pull out the little girl's Teddy bear. "Can't leave a man behind!" he manages to croak. (Oddly, that's his only line of dialog in the entire movie.) SteveBaker (talk) 22:47, 16 June 2014 (UTC)

That's not a bad plot for a movie, by contemporary standards. But as for the OP's question, I don't understand. You're asking how to seal a leak in a "partly melted" tank that has been broadly ruptured by an avalanche? I don't think that's happening. I mean, you're talking about essentially underwater welding, only it's under sulfuric acid, of a huge hole, in an unstable tank. Wnt (talk) 18:55, 16 June 2014 (UTC)

Not really -- the tanker truck is sitting in a shallow pool of acid, which is flowing downhill (and AWAY from the truck) under its own weight. And on second thought, it won't really be "partly melted" like I thought -- the large volume of acid will act as a heat sink to some extent, keeping the metal temperature down to 300 C or so (but also creating the risk of a catastrophic BLEVE). 24.5.122.13 (talk) 22:56, 16 June 2014 (UTC)

Well, if sulfuric acid is running through a crack or hole, there's going to be at least a lot of fluid behind it and some pouring through. It still seems like it would be hard to weld it, though I'm no expert. And there's just a huge gap in credulity - why would someone hang out next to this bomb, fooling around trying to plug a hole so acid won't leak out, instead of fleeing and waiting for a remote solution? Sulfuric acid going in a watershed would be bad for the fish, sure, but I don't think many people have that kind of commitment to the ecology. Wnt (talk) 08:04, 17 June 2014 (UTC)

See above, per the OPs story some people near and/or in the sulfuric acid are trapped but alive so need to be rescued. (That said, I agree with Mr.Z-man that it seems difficult to have a story line where the parties are still alive in a crash with an outcome like this. And further, even if they were alive but trapped, it seems difficult to have a scenario where it's necessary to close the hole to rescue them as opposed to very carefully extracting them, a scenario where anyone is laying in concentrated sulphuric acid but alive seems particularly unplausible. Although from some of their questions particularly last year, I'm not sure if the OP is aiming for hyper-realism anyway.) Nil Einne (talk) 13:31, 17 June 2014 (UTC)

As a matter of fact, I AM aiming for at least a halfway-plausible scenario -- that's why I'm asking these sorts of questions instead of just writing the first thing that comes to mind. Unlike many of today's writers, I do NOT judge my works by the standards of 1970s disaster films -- I strive to make my work better than those. Which is why I've reconsidered the part about the acid immersion: upon reading your responses, I've decided that any casualties actually immersed in the pool of acid will die, and only those plucked from its path in time will survive. Also note that I did not specify that the hole must be closed in order to save the trapped casualties -- on the contrary, the casualties will be extricated first, and then the hole will be closed with epoxy (NOT welding -- that would be too dangerous, as Plasmic pointed out) to prevent the acid from spreading and endangering other people in the vicinity. 24.5.122.13 (talk) 00:31, 18 June 2014 (UTC)

Seems like a crane or a helicopter would be the easiest way to extricate the victims from the acid flood. But the conditions necessary for this to happen are pretty seriously contrived. Mending the hole in the tanker isn't going to get rid of the flood of acid that has them trapped anyway. Basically, any hole thats big enough to create a flood of acid that you couldn't easily run away from would be much too big to fix - and in any case, the tanker would be empty long before anyone could figure out a way to fix it and get the necessary equipment in there. Personally, I'd bet you could back a pickup truck through the acid, have the victims hop aboard and then drive slowly out again before the tires were destroyed sufficiently to prevent the truck from moving. Even if it's down to the rims, it would move well enough to get out. SteveBaker (talk) 15:13, 17 June 2014 (UTC)

Note as mentioned above, the acid is supposed to be pouring down a hill so possibly shouldn't be too pooled if there is way to stop the leak. (That said, I do agree as I mentioned that there are problems with the scenario in addition to whether it makes any sense to save some one that way even in the scenario.) Nil Einne (talk) 15:22, 17 June 2014 (UTC)

A helicopter is precisely what I plan to use to extricate the casualties (in any case, the avalanche has blocked the only road, so only a helicopter or a bulldozer can get there anyway). And the hole is pretty small, so the acid is coming out slowly -- but the casualties CAN'T run away because they're too badly hurt (concussions, broken bones, shock, that kind of thing). 24.5.122.13 (talk) 00:31, 18 June 2014 (UTC)

(un-indent) OK, let's see if I got the main points right: (1) Epoxy is a fairly safe and effective way to seal the hole in the tanker truck, whereas welding is dangerous; (2) The victims will have to be extricated first, before dealing with the leaking acid (but not until the gas fire is out); and (3) Those casualties which were immersed in acid will almost certainly die. Is that correct? 24.5.122.13 (talk) 23:52, 18 June 2014 (UTC)

Well, that's not very plausible. So you mix up your epoxy, which you happen to have lying around someplace nearby. Then you smear a big goop of it over this hole - while the acid is still pouring out...but won't the pressure of all that liquid just force the not-yet-set epoxy away from the hole? What holds the epoxy in place against all that pressure for the five or so minutes it takes to set? A liquid-carrying tanker probable has a tank that's a couple of meters tall - so the pressure at the bottom (where, I suppose the leak is at) will be pretty high. Conc. sulphuric acid has a density close to twice that of water - so at the bottom of the tank, the pressure will be really quite high. It might be like trying to fill the end of a garden hose with epoxy while the water is turned on. Added to which, if you don't cover the hole just right, you're going to have the stuff squirt out in all directions - which is bad news for the person applying the epoxy.

Honestly, this story has BOGUS written all over it. SteveBaker (talk) 05:11, 19 June 2014 (UTC)

OK, what then? Should the rescue crew try to offload the acid from the leaking tanker truck into, say, a portable storage tank of some kind, and just hope that not too much acid leaks out in the meantime? (That would also take care of the BLEVE hazard.) Or maybe they could try to jack up the leaking end so that the rupture is above the level of the acid (is that even possible?) 24.5.122.13 (talk) 05:35, 19 June 2014 (UTC)

If the goal is simply to get some people out alive without a BLEVE going off in the meanwhile, couldn't you just open whatever normal valve or relief valve is available and let the stuff pour out? Why do you need to stop the leak at all, when you're worried the whole thing is going to blow up from the pressure??? (But if there's pressure, how big a hole can it really be?) Or empty your service revolver into the furthest end of the truck? (not sure it will penetrate) In general, if you can't stop the heat from building up, you don't want to stopper the bottle better. I think you should reevaluate the scenario from first principles...

Oh, and please consider carefully before aiming your fire hose into the truck... what was that rhyme, water to acid keeps things placid... :) Wnt (talk) 16:37, 19 June 2014 (UTC)

OK, I've made up my mind -- they'll offload the acid from the leaking tanker truck into another, intact, tanker, and thus contain the leak. (Not sure where they'll find the other tanker, though, or how they'll get it to the site, given that the avalanche has cut the only road; they might have to sling it all the way from Edmonton.) As for the BLEVE hazard, simply putting out the gas fire (and the forest fires which it had ignited) will prevent it by removing the source of heat. (On second thought, I think they'll first try the epoxy trick as a desperate measure, only to have it promptly blow out due to the hydrostatic pressure -- as Steve Baker pointed out will happen in real life.) 24.5.122.13 (talk) 00:03, 20 June 2014 (UTC)

Why can't people bring dead people back to life?

Cartoon of a galvanised corpse 84.209.89.214 (talk) 22:07, 16 June 2014 (UTC)

In Frankenstein, the titular science nerd makes a monster out of dead body parts. It's unclear how he did it, but he did it. Although his scientific methods aren't the main point of the story, what is the difference between life and non-life? 140.254.226.242 (talk) 17:30, 16 June 2014 (UTC)

It isn't clear how he did it because he didn't do it. Remember that that story is fiction. Mary Shelley didn't have to specify how he did it. The genre that we call science fiction hadn't yet been defined (being invented decades later by Jules Verne and H. G. Wells), but she followed the rules of science fiction in not specifying things that she didn't have to specify. Robert McClenon (talk) 18:09, 16 June 2014 (UTC)

Our article on life points to one definition in the opening paragraph: "Life is a characteristic distinguishing objects having signalling and self-sustaining processes from those that do not, either because such functions have ceased (death), or because they lack such functions and are classified as inanimate". Several other definitions of what constitute "life" are listed under definitions in the same article. WegianWarrior (talk) 17:40, 16 June 2014 (UTC)

In general, necrosis involves a loss of cell membrane integrity, i.e. the cells physically break down in a way that makes it very difficult to restart them. For example, a neuron with even a small hole in it is not going to be sending any signals, because those are charges on opposite sides of the membrane. Now tissue death does occur over a period of time, and some people are hopeful that current practices in resuscitation can be improved on, but no bolt of lightning is going to unscramble an egg. This leaves the remaining hope that somehow you can "forensically" resurrect a person by some kind of brain scan that tracks every neuron and figures out (somehow) what synapses and long-term potentiation they had, and makes a reasonably accurate duplicate. But whether such a duplicate would be that person, or whether anything but a true tissue printer generated flesh and blood duplicate even could be any person, is philosophically very debatable. Wnt (talk) 18:32, 16 June 2014 (UTC)

if you take the time backword and change the corse , it call " the next world " thanks water nosfim — Preceding unsigned comment added by 192.116.142.154 (talk) 19:09, 16 June 2014 (UTC)

Frankenstein doesn't hold together for any number of reasons that were not understood when it was written (how about organ rejection in a body sewn together from 30 different cadavers!) - so let's just discount that.

One major problem is the cause of death in the first place. In order for someone to have died, something fairly bad must have happened to their body systems - and repairing that would obviously have to take place before one could even consider reviving them. That said, there has been a recent application for human trials of a technique where severe trauma patients would have all of their blood replaced with chilled saline - stopping all of their life signs completely - and then reviving them after an hour or so once the trauma team have patched up whatever needed fixing. Since the lack of all clinical signs of life means "death", they will (technically) be reviving the recently dead. SteveBaker (talk) 19:20, 16 June 2014 (UTC)

Imagine a volume like a cubic foot filled with water. Then imagine that somehow at the start of the process the water had small areas with higher temperature. Another point is that this volume is absolutely isolated from the outside world. What would happen after a while? The water's heat, thermal energy from areas with higher temperature will flow to the areas with lower energy and soon the whole volume will assume equal temperature. Can this system go back in time and internally recreate the difference in energy across the volume without outside intervention? No, it contradicts the Second Law of Thermodynamics. The same is with the human/animal body. Any animal body contains billions of cells with membranes with electrical gradient across them. It is maintained by ion pumps that pump sodium out of the cells into the inter-cellar medium and potassium the other way around. Aside from those two ions dozens of other substances are moved across the membranes all the time. When a person dies the pumps stop and the gradients get equalized. Restarting them contradicts the Second Law of Thermodynamics therefore bringing dead people back to life will never happen. --AboutFace 22 (talk) 21:49, 16 June 2014 (UTC)

you can take back only information , change the corse of the dead one ,it statistic ocar in flaktation , and you can stabilize on the write superposition . thanks water nosfim — Preceding unsigned comment added by 192.116.142.154 (talk) 04:30, 17 June 2014 (UTC)

Mary Shelley wrote Frankenstein in 1818 when the mainstream vitalist notion was that a living organism differs from the non-living in that it posesses a unique "vital spark", associated in Western medicine with Hippocrates' Four temperaments and humours, and called its Élan vital by Bergson in 1901. The pre-Christian Stoic philosopher Posidonius postulated that such a "vital force" emanates from the sun to all living creatures. Shelley built her story on this thinking (that could not be seriously challenged in the scientific world until synthesis in 1828 of Urea CO(NH₂)₂ previously thought to be only a by-product of life) and on the effects of electricity on dissected animals reported by Galvani. While she makes no direct mention of electrical reanimation in the novel Frankenstein, film adaptations typically show electrical laboratory equipment and the monster's awakening is brought about by an electrical storm. The OP is correct that Victor Frankenstein's scientific methods aren't the main point of Shelley's seminal "soft" science fiction story. Its subtitle The Modern Prometheus refers to a Latin myth of Prometheus who makes man from clay and water, like Victor rebelling against the laws of nature (how life is naturally made) and as a result is punished by his creation. 84.209.89.214 (talk) 22:07, 16 June 2014 (UTC)

The description of temperature equalizing in a volume of water is a great statement about the laws of thermodynamics - but the analogy is seriously flawed.

We can easily heat up the water again and restore the original patchy variations of temperature using appropriate heat sources brought in from outside. All that tells us is that a "sufficiently dead" body cannot simply come back to life by itself (although there are energy stores in fat deposits in a dead body - so even that limited interpretation is not prohibited by thermodynamics). The "rules of the game" here are that we can use any reasonable amount of external input in re-animating the dead. (For example: A handy lightning storm - to follow the OP's line of thinking). So the laws of thermodynamics (which apply only to closed systems) are simply inapplicable here. SteveBaker (talk) 22:26, 16 June 2014 (UTC)

SteveBaker, I did not expect you to fight for the lost cause. Had a living body had just 10 cells (compartments with temperature and concentration gradients) it would have been one thing, but a human body has billions of such compartments just in the brain. No lightning will ever help you and no energy stored in fat either. --AboutFace 22 (talk) 01:02, 17 June 2014 (UTC)

I'm not saying that lightning or fat deposits will do the job - what I *AM* saying is that an argument that the second law of thermodynamics is proof that resuscitation is impossible is nonsense. The second law only covers closed systems and that's not what we're talking about here...and even as a closed system, the body has considerable energy reserves - so a thermodynamic argument simply cannot be employed here. Your bucket of water can return to it's former state if there are heating coils and a fully charged battery.

Don't get me wrong though - I agree that there are hard-to-reverse problems with a dead body that would make it insanely difficult to "fix" it. My only beef is that your "proof" of that by reference to the 2nd law is nonsense - and therefore subtracts from the argument instead of adding to it - which is why I feel the need to correct you. SteveBaker (talk) 05:23, 17 June 2014 (UTC)

Ms. Shelley may have been familiar with the 1803 experiment by Professor Giovanni Aldini, Galvani's nephew, who used a powerful battery to produce movements in the dead body of executed murderer George Forster, whose spinal cord had been severed and whose blood had been drained after his hanging. A contemporary account said "On the first application of the process to the face, the jaws of the deceased criminal began to quiver, and the adjoining muscles were horribly contorted, and one eye was actually opened. In the subsequent part of the process the right hand was raised and clenched, and the legs and thighs were set in motion." Edison (talk) 02:05, 17 June 2014 (UTC)

OMFG "one man, Mr Pass, the beadle of the Surgeons' Company, was so shocked that he died shortly after leaving." The salad days of science! But nonetheless, this only works with a fresh corpse where many of the cells are still alive.

As for the thermodynamic argument: it is true that you can unscramble an egg with excess energy input, and some really sophisticated nanotech. I mentioned an approach with a tissue printer, but I suppose there are other ways to try to reform every cell as it was. But if you don't do it precisely as it was, is it the same person? For believers in atman this is an easier question for others, but even then, you have to ask how good it has to be to be a person at all. Which requires understanding of consciousness, which is a paranormal phenomenon. There is no known experiment to show that an arbitrary computational device "really feels something" as opposed to "being programmed to exclaim its discomfort". It is, therefore, necessary to develop a theory of the paranormal in order to answer the question in that case. I've made some comments on this regard in the past here but I fear I may try on the audience's patience to do so again, especially considering it's a Science desk. Wnt (talk) 04:00, 17 June 2014 (UTC)

People have been bringing people back to life for eons, by burying them in soil. They sprout or hatch, they grow, they eat, they breed and age and die again. Return to life isn't what the bereaved in Pet Sematary, "The Monkey's Paw" or Game of Thrones really want. They want to go back in time, and enjoy the same face/personality they remember. That's the hard part, even within one lifespan.

Frankenstein couldn't have convinced the family of the man he got the monster's heart from that its beating meant he was alive again. Neither the brain donor's, even if the monster remembered private moments. Stitching a face onto a complete living stranger and giving him the backstory would be far more likely to fool us (though hopefully still rather unlikely). InedibleHulk (talk) 05:11, 17 June 2014 (UTC)

Blood alcohol content

If water doesn't reduce BAC, why is it that downing a glass of water between drinks or even diluting strong alcoholic drinks with water, reduces the effects of alcohol? — Preceding unsigned comment added by 2.221.70.208 (talk) 20:14, 16 June 2014 (UTC)

Alternating alcoholic drinks with water can reduce your overall intake of alcohol if you take your time drinking the water, so that would indirectly reduce your blood alcohol content (BAC). But otherwise you're right, just very quickly drinking a glass of water between alcoholic drinks won't affect BAC and intoxication (reduced motor skill, slurred speech, etc.). However, alcohol has other effects besides intoxication. Alcohol consumption causes body dehydration, which produces headache, tiredness, etc., usually several hours later. Drinking water between alcoholic drinks helps prevent dehydration and may reduce some of those effects.--Dreamahighway (talk) 21:16, 16 June 2014 (UTC)

However, drinking a glass of water before using a breathalyser does reduce the reading sometimes. Presumably it flushes some of the alcohol off the surface of the mouth and gullet. Greglocock (talk) 22:43, 16 June 2014 (UTC)

If someone has had enough alcohol to potentially fail a breathalyzer test, they ought not be driving. Tricking the cops into thinking the driver is sober could have fatal consequences. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:36, 17 June 2014 (UTC)

Thank you for the lesson in morals, wrong forum. The instructions for my breathalyser tell you to do that. 23:20, 18 June 2014 (UTC)

This use of water is not a trick. Technically blood alcohol is best measured by blood, yielding a value for what the brain actually experiences. The breathalyzer is merely a surrogate test. Flushing alcohol out of the mouth will, if anything, increase the blood alcohol level; it only removes the spurious contribution of recently consumed alcohol. Now sure you could say that really the cops in a jurisdiction with a .08 ought to run in people who blow .07, .06, .05 just for the principle of the thing - that's how Wikipedia admins tend to act, after all - but that is typically regarded as a matter for politics. I see on reading the article that some states have actually made the BrAC levels legally binding ... which must be interesting when someone has only used mouthwash (as the article details) and can prove it with a negative blood test result.

Followup question: what determines the 2100:1 partition ratio the article says is programmed into the machines? I'm seeing a value of 2300 in the literature and a statement that it is acceptable for use in individuals with "normal pulmonary function" [1]. There must be some people getting badly screwed by the testing procedure, but I'm not sure at this point who. Wnt (talk) 20:19, 17 June 2014 (UTC)

Unless I missed something, there's nothing in our article suggesting mouth wash will cause a significantly false reading in an evidentary breath test 15 minutes after consumption which as per our article, is evidentally the norm before testing.

Actually the time between consumption and testing is likely to be higher, I presume the evidentary breath test machines in the US are like the ones here and are big enough (our article mentions some portable evidentary units but doesn't elaborate they are used and the info would suggest not much if at all) that they are only generally stored in the police station (plus observing the suspect out in the field seems problematic) so unless the suspect is very stupid and secretly drinks mouth wash in the police car on the way to the station, it's probably 25+ minutes (even if the police station is only 5 minutes away it's likely to take 5 minutes at least for processing etc before the suspect is put under observation for the test) before the testing in the mose cases. (There are sometimes mobile units stored in a bus but I don't know what percentage of suspects they process and whether they even follow the same procedure or have extended waiting times.)

Of course this may not help in other cases like belching, but you only mentioned mouth wash.

P.S. Our article suggests most/all? states in the US with evidentary breath tests make it rebutable. In other words if the suspect has a reliable blood alcohol test from the time of the test, it's likely a simple matter of presenting that evidence. It doesn't specifically mention, but I'm presuming in most of the US as in NZ, the blood test is up to the suspect. They can either choose to take the blood test instead of the evidentary breath test or can choose to take the blood test if they fail the evidentary breath test [2], at the financial expense of the government as with the other tests. This doesn't of course help those who have an extreme fear of needles or whatever that will prevent a blood test. But for the rest, it's probably not even normally a case of needing to present the evidence. If you don't trust the breath test, just choose the blood test, it seems unlikely you'll even be charged if you pass regardless of what happened with the evidentary breath test.

Nil Einne (talk) 00:04, 18 June 2014 (UTC)

Today's breathalyzers are sophisticated enough to exclude mouth alcohol or any alcohol other than the blood-gas exchange of the lungs. It's the reason why continuous blowing is required. The machine is looking for a curve that matches lung alcohol. Once that curve is detected, the reading is made. Anything but that curve is invalid. --DHeyward (talk) 05:31, 18 June 2014 (UTC)

Thanks! - I did not have any inkling of that. Wnt (talk) 17:39, 18 June 2014 (UTC)