# What prevents a fuel-cell vehicle from blowing up like the Hindenburg? **URL:** \ **Category:** Factual Questions\ **Created:** [October 12, 2013, 11:42pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103 "2013-10-12T23:42:25Z")\ **Posts on this page:** 19\ **Page:** 2
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 13, 2013, 8:55pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/21 "2013-10-13T20:55:45Z")
Yeah, the hydrogen can get to all of the oxygen it wants, _if it rises up away from the car_. Once it’s up there, I don’t care what it does. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [October 14, 2013, 1:15am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/22 "2013-10-14T01:15:15Z")
> [@Chronos](#): > > It’s actually very difficult to get hydrogen to explode. It’ll burn, sure, and fairly quickly, but it’s also rising away from the source while it’s burning, and so does very little damage. The problem with the Hindenburg wasn’t that the hydrogen was burning; it was the envelope. The envelope of the Hindenburg was treated with a substance that is basically thermite, which behaved about how you’d expect thermite to behave. Yes, most people still have a hard time accepting it but it’s been fairly well proven that it was the zeppelin’s aerodynamic outer skin which ignited. It was painted with a doping agent containing powered aluminum (essentially rocket fuel). NOVA did an episode about this. For the finale they took a small souvenir sample of the Hindenburg’s actual skin and tested it’s flammability to static electricity. It went up like flash paper! > [@Cheesesteak](#): > > Is it inherently worse than a widening pool of flammable gasoline, from a punctured gas tank? Hydrogen, at least, will dissipate faster in an open air environment. In another much older episode of NOVA (maybe 25 or 30 years ago) about hydrogen powered vehicles they did a demonstration where they took a jerrycan of gasoline and a tank of pressurized Hydrogen and shot both with a high powered rifle. The gasoline erupted into a huge fireball which being liquid spread out and burned a large area (and remained burning). The Hydrogen tank didn’t explode, the hole caused it to shoot across the ground a short ways while a jet of burning gas came out. It set nothing else on fire, remained contained to a very small area, and went completely out in only a couple of seconds. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [October 14, 2013, 1:42am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/23 "2013-10-14T01:42:52Z")
Hydrogen storage tanks for vehicle use can be constructed containing [metal hydride granules,](https://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydrides) which render the gas much safer in case of an accident. Here is a[video which demonstrates the technology.](http://www.youtube.com/watch?v=n0a5IXjh8Mg) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 14, 2013, 4:12am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/24 "2013-10-14T04:12:34Z")
Huh, I had understood that the main benefit of the metal hydride was density of storage, not safety. ---
**Author:** ![Glazer](https://avatars.discourse-cdn.com/v4/letter/g/a88e57/32.png) [@Glazer](https://boards.straightdope.com/u/Glazer)\ **Post date:** [October 14, 2013, 4:15am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/25 "2013-10-14T04:15:00Z")
It is, but safety makes a better selling point. ---
**Author:** ![Try2B\_Comprehensive](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/try2b_comprehensive/32/65_2.png) [@Try2B\_Comprehensive](https://boards.straightdope.com/u/Try2B_Comprehensive)\ **Post date:** [October 15, 2013, 2:33am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/26 "2013-10-15T02:33:17Z")
> [@Fear\_Itself](#): > > Hydrogen storage tanks for vehicle use can be constructed containing [metal hydride granules,](https://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydrides) which render the gas much safer in case of an accident. Here is a[video which demonstrates the technology.](http://www.youtube.com/watch?v=n0a5IXjh8Mg) The “sorry, you lost!” at the end was a little extraneous, but otherwise that’s a pretty convincing video, along with the other points. Learn something every day here, thanks, everybody. ---
**Author:** ![Aeschines](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aeschines/32/16251_2.png) [@Aeschines](https://boards.straightdope.com/u/Aeschines)\ **Post date:** [October 15, 2013, 9:47am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/27 "2013-10-15T09:47:25Z")
I’ve done translation about fuel cell vehicles quite a bit for a major automaker. It’s mostly all been said above, but hydrogen is a much safer fuel than gasoline: • It floats up instead of pooling on the ground. • It cannot get on you or soak into your clothing. • It’s non-toxic. • It actually doesn’t explode very easily. In the Hindenburg disaster, most of the passengers and crew _survived._ It was on fire, but they dragged it down with the ropes, and people got off. Per Wikipedia ([Hindenburg disaster - Wikipedia](https://en.wikipedia.org/wiki/Hindenburg_disaster)) Passengers 36 Crew 61 Injuries (non-fatal) unknown Fatalities 36 (13 passengers, 22 aircrewmen, one ground crewman) Survivors 62 H2 _cannot_ explode unless it’s thoroughly mixed with oxygen first. Keep in mind that an explosive like gunpowder or dynamite doesn’t _need_ oxygen to explode; it already includes the oxidizing agent within it. • As stated previously, hydrogen in a fuel cell vehicles doesn’t _burn._ It is combined with oxygen in a cold chemical reaction which releases electrons that power the vehicle. It _is_ an electric vehicle. That’s way companies now typically call their H2-powered cars “fuel cell electric vehicles.” How often in a collision does the gas tank rupture and cause problems? A compressed gas tank is much safer than a liquid fuel tank in a collision, so there are even fewer worries to have. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 15, 2013, 5:37pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/28 "2013-10-15T17:37:23Z")
> [@](#): > > It’s mostly all been said above, but hydrogen is a much safer fuel than gasoline: Is that a like-to-like comparison, though? If you have two tanks of the same size and reasonable pressure, then the hydrogen one is going to have a much lower energy content, and so it’s not surprising that it’d be safer. To get the same energy per volume, you’d need to compress the hydrogen pretty far, and that pressure could itself be dangerous. Or if you’re just settling for a lower energy content, you could compare it to a smaller gasoline tank. ---
**Author:** ![Aeschines](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aeschines/32/16251_2.png) [@Aeschines](https://boards.straightdope.com/u/Aeschines)\ **Post date:** [October 16, 2013, 5:03am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/29 "2013-10-16T05:03:00Z")
> [@Chronos](#): > > Is that a like-to-like comparison, though? If you have two tanks of the same size and reasonable pressure, then the hydrogen one is going to have a much lower energy content, and so it’s not surprising that it’d be safer. To get the same energy per volume, you’d need to compress the hydrogen pretty far, and that pressure could itself be dangerous. Or if you’re just settling for a lower energy content, you could compare it to a smaller gasoline tank. Here are the specs for the the FCX Clarity, an actual fuel cell electric vehicle on the road in the US: > **[Honda Motor Co.,Ltd.｜Honda Global Corporate Website](https://global.honda/en/)** > > Visit Honda’s official corporate website for company details including sustainability, investor relations, newsroom, and employment opportunities. Fuel Type Compressed hydrogen gas Storage High-pressure hydrogen tank Tank capacity (L) 171 Max. pressure when full(MPa) 35 Maximum speed (mph) 100 Driving range (miles) 240 That driving range is not amazing, but it is also within a fairly normal range. I am just saying that, personally, I would be less afraid of that H2 tank causing harm to me in a wreck than of a regular gas tank (although I would not be particularly afraid of either). I would also be less afraid of a tanker truck carrying H2 than of one carrying regular gasoline. Time will tell what kinds of safety record these things end up having, but I see no reason to think that H2 is a much safer fuel to handle and use overall. ---
**Author:** ![Aeschines](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aeschines/32/16251_2.png) [@Aeschines](https://boards.straightdope.com/u/Aeschines)\ **Post date:** [October 16, 2013, 5:14am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/30 "2013-10-16T05:14:17Z")
> [@Chronos](#): > > you’d need to compress the hydrogen pretty far, and that pressure could itself be dangerous. This technology is already tried and true. In Japan, I believe that virtually all taxis run on natural gas. The Civic GX, which has been around for awhile, is a natural gas vehicle: [http://automobiles.honda.com/civic-natural-gas/specifications.aspx](http://automobiles.honda.com/civic-natural-gas/specifications.aspx) It lists tank pressure as 3,600 psi, which is 24.8 MPa. So the 35 MPa for the FCX Clarity fuel cell vehicle is hardly anything out of the ordinary at this point. I googled and saw links for 70 MPa storage technology. I am looking at google results for helium tank pressure and am seeing 1,750 psi, which is 12.1 MPa. That’s the pressure of gas tanks just being thrown around on a truck with nobody worrying about an explosion or anything. So I doubt that just 3x that pressure is anything too scary or high-tech. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [October 16, 2013, 6:23am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/31 "2013-10-16T06:23:53Z")
> [@Chronos](#): > > Is that a like-to-like comparison, though? The answer is not straight forward. Hydrogen has 4 times lower flammability limit but it is prone to leaks. There were also tests to show that a hydrogen fuel source in a car was less prone to explosion compared to a gasoline powered car in a collision scenario. Now leaks while the car stays in the garage is another thing. You can read the above and a lot of other considerations in this good report : [Hydrogen vehicle safety report](http://www.directedtechnologies.com/publications/storage/H2VehicleSafetyReport97-05.pdf) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 16, 2013, 2:04pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/32 "2013-10-16T14:04:52Z")
OK, then, that does look reasonably close. ---
**Author:** ![BrickaBracka](https://avatars.discourse-cdn.com/v4/letter/b/c5a1d2/32.png) [@BrickaBracka](https://boards.straightdope.com/u/BrickaBracka)\ **Post date:** [October 16, 2013, 2:20pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/33 "2013-10-16T14:20:52Z")
> [@Hail\_Ants](#): > > In another much older episode of NOVA (maybe 25 or 30 years ago) about hydrogen powered vehicles they did a demonstration where they took a jerrycan of gasoline and a tank of pressurized Hydrogen and shot both with a high powered rifle. The gasoline erupted into a huge fireball which being liquid spread out and burned a large area (and remained burning). > > The Hydrogen tank didn’t explode, the hole caused it to shoot across the ground a short ways while a jet of burning gas came out. It set nothing else on fire, remained contained to a very small area, and went completely out in only a couple of seconds. WIN! I can’t find that specific episode, do you have a link? Or maybe just some better keywords to search it by than “nova pbs hydrogen fuel cell” But as is expected, in 'Murica, different = scary = bad = evul = kill it dead. I for one hope we find a way to switch to hydrogen powered cars; that we’ll find a way of inexpensively releasing the hydrogen we need for it. ---
**Author:** ![glaeken](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@glaeken](https://boards.straightdope.com/u/glaeken)\ **Post date:** [October 16, 2013, 2:57pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/34 "2013-10-16T14:57:11Z")
Sort of related I guess but I find it was interesting just how difficult it was to shoot down Zeppelin bombers during WW1. You would think a Zeppelin should be very simple to shoot down but it took quite a bit of experimentation to come up with an ammunition type that would actually work. They initially tried incendiary bullets which totally failed to do anything due to the lack of oxygen in the hydrogen bags. They then tried alternate incendiary and explosive bullets which was eventually successful but it was still far from easy. There are some details on this on the below along with quite a few other methods that were tried. > **[BBC - Home](https://www.bbc.co.uk/)** > > The best of the BBC, with the latest news and sport headlines, weather, TV & radio highlights and much more from across the whole of BBC Online. It’s such a counter intuitive thing to think that for a time there was virtually no defence against Zeppelin’s. It’s amazing considering how fragile you would think they would have been. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [October 17, 2013, 3:47am UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/35 "2013-10-17T03:47:18Z")
> [@BrickaBracka](#): > > WIN! I can’t find that specific episode, do you have a link? Or maybe just some better keywords to search it by than “nova pbs hydrogen fuel cell” > > But as is expected, in 'Murica, different = scary = bad = evul = kill it dead. > > I for one hope we find a way to switch to hydrogen powered cars; that we’ll find a way of inexpensively releasing the hydrogen we need for it. I looked too, but couldn’t find it. Like I said, it was a \*long \*time ago, the early 80s or maybe even the very late 70s! ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [October 17, 2013, 4:24pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/36 "2013-10-17T16:24:17Z")
> [@Try2B\_Comprehensive](#): > > And I can see the buoyancy of hydrogen causing it to come into contact with all the oxygen it needs to combust quickly, instead of just sitting there in an air-excluding liquid form like gasoline. In an accident, isn’t there the potential to burn a whole lot of hydrogen really, really fast, possibly in a way that might as well be an explosion? Maybe this is piling on, but I’ll go ahead and point out that gasoline doesn’t just sit there in an air-excluding form; it creates a lot of (flammable) vapor quickly. So if there’s some kind of accident that creates an enclosed space with just the right proportion of air (oxygen) and flammable gas and adds a spark, a pool of gasoline at the bottom of the space is just as dangerous as a slowly leaking hydrogen tank, as far as potential explosions go. ---
**Author:** ![Try2B\_Comprehensive](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/try2b_comprehensive/32/65_2.png) [@Try2B\_Comprehensive](https://boards.straightdope.com/u/Try2B_Comprehensive)\ **Post date:** [October 18, 2013, 2:15pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/37 "2013-10-18T14:15:36Z")
This board is all about piling onto ignorance, so go for it. As for hydrogen vs. gasoline in an enclosed space, isn’t hydrogen actually more flammable? That is really at the bottom of my question here- I have the impression that hydrogen is especially flammable and explosive under the right conditions, more so than other fuels. It seems settled that the hydrogen tanks aren’t especially dangerous, but under ‘ideal explosion conditions’, doesn’t hydrogen still go KABOOM more than most things? ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [October 18, 2013, 2:50pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/38 "2013-10-18T14:50:38Z")
> [@Try2B\_Comprehensive](#): > > This board is all about piling onto ignorance, so go for it. > > As for hydrogen vs. gasoline in an enclosed space, isn’t hydrogen actually more flammable? That is really at the bottom of my question here- I have the impression that hydrogen is especially flammable and explosive under the right conditions, more so than other fuels. It seems settled that the hydrogen tanks aren’t especially dangerous, but under ‘ideal explosion conditions’, doesn’t hydrogen still go KABOOM more than most things? What’s your scale? If we compare [heat of combustion](http://en.wikipedia.org/wiki/Heat_of_combustion), hydrogen gets nearly three time the energy of the closest competitor (methane) when the scale is energy per mass of fuel. But hydrogen molecules are tiny, so if we look at energy per mole, the numbers reverse. Methane of course would require more oxygen per mole, so estimating explodiness gets complicated fast. Without drawing any conclusion on whether hydrogen is more kaboomy, I’ll hazard the guess that your impression that it is so stems from its prevalence as a science experiment. But that has its roots in the relative ease of producing suitable amounts of hydrogen, and how safe the resulting explosion is, rather than in inherent bangitude. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [October 18, 2013, 3:59pm UTC](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103/39 "2013-10-18T15:59:43Z")
> [@Try2B\_Comprehensive](#): > > As for hydrogen vs. gasoline in an enclosed space, isn’t hydrogen actually more flammable? **NO**. Consider Ignorance fought. The LEL/LFL (Lower Explosivity Limit / Lower Flammability Limit) (in % by vol of air) for Gasoline is 1.4. For Hydrogen, it is 4/18.3. Simply put, you need a lot less gasoline in air for it to be flammable. > [@Try2B\_Comprehensive](#): > > I have the impression that hydrogen is especially flammable and explosive under the right conditions, more so than other fuels. That impression is incorrect. Check this link for[flammability in Wikipedia](http://en.wikipedia.org/wiki/Lower_explosive_limit). You will find lots of other fuels more flammable (i.e. lower LEL/LFL). > [@Try2B\_Comprehensive](#): > > …but under ‘ideal explosion conditions’, doesn’t hydrogen still go KABOOM more than most things? **Again, NO.** If you are reading still, you know why. [Previous page](https://boards.straightdope.com/t/what-prevents-a-fuel-cell-vehicle-from-blowing-up-like-the-hindenburg/671103.md?page=1)