Hydrogen car leaks/fire not so bad?

What specific type of scenario were they trying to recreate?

The chance of a fire in a car collision is under 1%, and there are safety devices, like a pump cut off switch, to limit the severity if there is a fire. Then many parked car fires are because of something other than the fuel. Recalls for car fires are usually because of faulty electrical switches. The motor oil, transmission fluid, power steering fluid, and brake fluid are also flammable if they get exposed to enough heat. Park a car over dry grass and the heat of the catalytic convertor can start a fire.

I also expect a hydrogen car to be as likely to catch fire as a gasoline one in an accident, and parked fires could occur for reasons besides the fuel.

So what was this study actually studying? Or was it just to make some pretty pictures.

 

Which is basically saying to make propaganda, if there is no expression of the likely hood of either event to happen.
Car fires are already unlikely to happen in the cars available today, and I expect those designing the safety systems on hydrogen cars today are using due diligence in their task.

 

Hydrogen shoots up because it is lighter than air. The flames go up and behaves differently than gasoline or Lithium battery fire.

Hydrogen vs Gasoline



Model S fire:

 

And in an enclose space, like a garage, the battery fire will be no different. Since the vapors are heavier than air, a fire from a gasoline leak would likely also be the same.
If the hydrogen leak happened as it does in the video, then the garage becomes a bomb.

But I am not questioning the fire safety measures on a FCEV. The lobby has more to lose than I do from any bad FCEV fires.

I am questioning the odds of the scenarios presented in the video actually happening out in the field.

Fires happening as a result of a crash are extremely rare now with gas cars. Many of the fires involving parked cars don't involve a fuel leak at all. Most appear to start from faulty electric switches. Does the Mirai have hand crank windows? Then parking with a hot catalytic convertor over some dry gas or leaves could end with the car looking much like the one in the video in the end.

In the video, the hydrogen leak is from the safety pressure release valve. Barring a defective one getting pass QA, that valve will only release when the pressure in the tank gets too high. For that to happen, the tank would have to get overfilled. Not likely to happen with the electronic controls involved in filling the car. Or the hydrogen tank would need to be heated up. Which would likely mean the car is already burning.

When this valve does blow, it does so through a vent line so that escaping gas can't get trapped in the nooks and crannies of the car frame. Then the valve blowing alone isn't enough to actually ignite the hydrogen. There also needs to be a spark or flame nearby. Same with the gasoline leak.

So igniting a jet of hydrogen that is already outside the body of the car isn't telling us anything about how well the fire safety measures for a hydrogen car are working, or even if they are working at all. How well are the fuel lines and tank connections going to hold up in a crash. There are hydrogen sensors that can detect leaks and shut off valves, but some hydrogen had to get out for them to work. Is that enough to pose a serious risk still if it got trapped under the car. Keep in mind hydrogen can ignite under a wide range of air to fuel ratios. The fuel cell and one of the tanks of the Mirai are underneath the passenger cabin. Hydrogen can get trapped in the tunnel they are sitting in, or are their vents to let the hydrogen escape from there in the event of a leak?

Or to make the hydrogen and gasoline fire situations comparable, put a hole in a hydrogen line underneath the car, and ignite the resulting leak.