The important part of good air shaft design is making them large enough to fit a squad of marines, and yet small enough not to fit biomechanoid xenomorphic invaders.
Isn't there also an important material selection choice to be made - your ducts (getting a bit Brazil about it) have got to be impervious to angry biomechanoid xenomorphs who can smash through thick steel doors but also easy enough to cut and weld with small handheld tools?