High Guard erratum

[mccambjd]

In High Guard Update 2022 on p. 134 in the side bar on fuel systems, it says [emphasis mine]:

In vacuum, fuel explosions inflict 8D damage with Blast 10, which typically consumes an entire compartment in a starship of under 1,000 tons...If the compartment does not have its oxygen evacuated, the explosion is much more severe...

Liquid hydrogen doesn't explode without an oxidizer (which is part of the reason why you're evacuating the air during combat).

What's the thinking here?

 

[MongooseMatt]

I think the presumption was that it was held under pressure rather than sloshing about (although I really like that idea!).

 

[Condottiere]

Directional.

It's why you have blow out panels.

 

[mccambjd]

No reason to hold liquid hydrogen under pressure--you can't really pack any more in per ton that way. Even if it were under pressure, a hole in the fuel tank or line would lead to a jet of cyrogenic liquid (which is plenty dangerous), but no explosion. Unless the "explosion" is meant to capture the effects of cyrogenic liquid flooding the compartment?

 

[Geir]

It wouldn't be pressurized - that's the problem with liquids, you can't crush them and hydrogen is, well, only as dense as the displacement ton lets it be. I can't remember enough chemistry to figure out how much energy a phase change (hydrogen steam explosion??) would cause if the hydrogen was introduced into an environment that was too warm for it to stay liquid, but it would not be zero and at the very least there would be an expansion of volume.

 

[mccambjd]

It wouldn't be pressurized - that's the problem with liquids, you can't crush them and hydrogen is, well, only as dense as the displacement ton lets it be. I can't remember enough chemistry to figure out how much energy a phase change (hydrogen steam explosion??) would cause if the hydrogen was introduced into an environment that was too warm for it to stay liquid, but it would not be zero and at the very least there would be an expansion of volume.

If you're wearing a vacc suit, cold expanding gas probably isn't a big problem. Cryogenic liquids filling the compartment might be, but I would hope fuel tanks are self-sealing against the kind of holes made by slug throwers or small energy weapons.

 

[Condottiere]

Relief is at hand.