great discussion so far! 
I see some common myths still being argued though!
I thought I would bring up some things I had to learn myself, and this information is based on actual things I had to learn for a previous job as a welding supply center service tech. Most of the handling, crash,and leak information related to my getting certified to be a delivery truck driver. ( Has Mat stuff plus strict company rules)
The information I had to learn showed Hydrogen is actually very safe when compared to the common fuels we dont even think about and use every day.
It dissipates extremely rapidly. If you were to dump a 500 gallon container of liquid hydrogen on the ground, in less than 3 minutes you could throw a match at that spot and have nothing happen!
Dump 500 gallons of gasoline on the ground and you have to worry about a spark for days!
Plus as the lightest of all gases, it rises in the atmosphere at nearly 40 mph assuming the turbulence from its own rising does not dissipate it first! Its upward travel rate is even faster than air bubbles rising in a column of water!
Trying to keep air and hydrogen mixed is like trying to keep air and water mixed. Every chance it gets it tries to rise and float away!
It’s hard to actually produce a natural combustion situation with it being able to dissipate so extremely fast!
Like air in water it will dissipate or get absorbed into the surrounding area but at a very low concentration. The majority of it tries to rise until it gets mixed with the air it’s in.
The actual effort it does take to keep it mixed with a contained air source makes it very hard to keep its air to fuel combustion ratios uniform. It wants to rise to the top of the container and that tends to disrupt the mix ratios.
As far as common dangerous gasses Acetylene, propane and natural gas are many many times more dangerous! That’s why they put the scenting agents in them! SO you can be aware if there is a buildup!
It is very hard to get a tank of hydrogen to spill. They are very well built! You wreck a hydrogen powered vehicle with a certified high pressure fuel tanks and I will guarantee the tanks full of hydrogen will be the last solid piece intact!
Also in an unconfined leak and ignition situation hydrogen does not actually explode with great force. It sort of just puffs up and rises away quickly. The actual thermal energy is not all that great either. Think of a big steam cloud more or less. It’s has far lower heat and less violent expansion than propane or even gasoline vapor combustion when unconfined!
Ever seen the myth busters’ episode where they try to shot a hole in a propane tank? It took a fair sized rifle to do it! And propane tanks are only rated at around 325 PSI venting pressure. The high pressure tanks are typically 3500 PSI or more at actual safety venting release pressures.
In my certification safety classes for work I had to watch several videos of the standard high pressure cylinders being placed in actual crash and abusive conditions. (It helps make new employees feel more confident and safer while handling and working around the high pressure tanks)
A truck load of high pressure cylinders (at working Pressures) was hit by a train on one video. (safety regulations test crash analysis) Two vented slightly out of something like 50 units. The rest survived and most were still certified as safe to use!
The truck however looked like it went through a hammer mill shredder!
It’s why I am rather on the less concerned side when it comes to working around it. I still respect it but I don’t fear every interaction with it.
I am not trying to make hydrogen sound like it’s completely harmless by any means. I am just trying to get more people to realize that it is actually a fair amount safer that what we commonly use every day!
Lack of familiarity and proper knowledge is what most of the hydrogen horror myths are really about.
With some good honest on-line searching you can find all of this information too!
I see some common myths still being argued though!
I thought I would bring up some things I had to learn myself, and this information is based on actual things I had to learn for a previous job as a welding supply center service tech. Most of the handling, crash,and leak information related to my getting certified to be a delivery truck driver. ( Has Mat stuff plus strict company rules)
The information I had to learn showed Hydrogen is actually very safe when compared to the common fuels we dont even think about and use every day.
It dissipates extremely rapidly. If you were to dump a 500 gallon container of liquid hydrogen on the ground, in less than 3 minutes you could throw a match at that spot and have nothing happen!
Dump 500 gallons of gasoline on the ground and you have to worry about a spark for days!
Plus as the lightest of all gases, it rises in the atmosphere at nearly 40 mph assuming the turbulence from its own rising does not dissipate it first! Its upward travel rate is even faster than air bubbles rising in a column of water!
Trying to keep air and hydrogen mixed is like trying to keep air and water mixed. Every chance it gets it tries to rise and float away!
It’s hard to actually produce a natural combustion situation with it being able to dissipate so extremely fast!
Like air in water it will dissipate or get absorbed into the surrounding area but at a very low concentration. The majority of it tries to rise until it gets mixed with the air it’s in.
The actual effort it does take to keep it mixed with a contained air source makes it very hard to keep its air to fuel combustion ratios uniform. It wants to rise to the top of the container and that tends to disrupt the mix ratios.
As far as common dangerous gasses Acetylene, propane and natural gas are many many times more dangerous! That’s why they put the scenting agents in them! SO you can be aware if there is a buildup!
It is very hard to get a tank of hydrogen to spill. They are very well built! You wreck a hydrogen powered vehicle with a certified high pressure fuel tanks and I will guarantee the tanks full of hydrogen will be the last solid piece intact!
Also in an unconfined leak and ignition situation hydrogen does not actually explode with great force. It sort of just puffs up and rises away quickly. The actual thermal energy is not all that great either. Think of a big steam cloud more or less. It’s has far lower heat and less violent expansion than propane or even gasoline vapor combustion when unconfined!
Ever seen the myth busters’ episode where they try to shot a hole in a propane tank? It took a fair sized rifle to do it! And propane tanks are only rated at around 325 PSI venting pressure. The high pressure tanks are typically 3500 PSI or more at actual safety venting release pressures.
In my certification safety classes for work I had to watch several videos of the standard high pressure cylinders being placed in actual crash and abusive conditions. (It helps make new employees feel more confident and safer while handling and working around the high pressure tanks)
A truck load of high pressure cylinders (at working Pressures) was hit by a train on one video. (safety regulations test crash analysis) Two vented slightly out of something like 50 units. The rest survived and most were still certified as safe to use!
The truck however looked like it went through a hammer mill shredder!
It’s why I am rather on the less concerned side when it comes to working around it. I still respect it but I don’t fear every interaction with it.
I am not trying to make hydrogen sound like it’s completely harmless by any means. I am just trying to get more people to realize that it is actually a fair amount safer that what we commonly use every day!
Lack of familiarity and proper knowledge is what most of the hydrogen horror myths are really about.
With some good honest on-line searching you can find all of this information too!
