if a ship has a barracks and it is holed, becoming depressurized, what happens to the troops? in most of the ship you have crew but the population density is much lower everywhere else. also most troops are use to planetary assaults, do all of them have void suits, or do you have a lot of dead troopers?

also what about fire? again you have a high population density, but these are trained soldiers. do their officers organize them to put out the fire?

the questions i suspose are: do you lose a higher percentage of crew from this hit? does the barracks still function normally? and if it catches fire do the troops try to put it out without being directed, do you get a bonus for directing them because there are so many, do they run away, or are many of them roasted du to lack of exits?

Well, if you're carrying troops in the barracks when it's holed, the standard procedure is for those troops to panic, the officers try and get some control over them but probably get caught up panicking themselves, and everyone tries to evacuate the compartment. You're probably going to lose a fair proportion of your soldiers, and they're definitely going to lose any equipment that would be damaged or destroyed by vacuum (cavalry beasts, for example).

As to crew losses in the affected section- yes crew density is going to be lower than the enginarium or a weapons battery, but so is the level of safety equipment (the crew assigned there as maintenance may not even have been issued with void suits, and if they have, those suits are likely to be stored somewhere they'll have difficulty getting to, thanks to the soldiers milling around). Crew losses are therefore going to remain around the same. (and embarked troops don't count towards crew).

Fire? Depends how good the troops are. Poor quality troops will get in the way, high quality troops will either know to get out of the way, or possibly (really only in the case of Best Quality infantry that've trained for shipboard duty) be able to aid in firefighting efforts. Remember a fire serious enough to be classed as a critical hit is pretty much a "burn this skyscraper to the ground" inferno. Smaller fires, they'll probably manage before the DC crews get to it.

This has cropped up for me, once. Resolved it as per a standard depressurisation, except that damage was dealt to the barracks population first, then to the crew on a 5:1 basis. Barracks population is one of those handwaved figures that's vaguely based on the general ship population.