There are a number of base facilities that you can place in your installations. Some of these are available from the beginning of the game, others are gained through research. With the exception of the Access Lift, and the facilites you start the game with, all require an amount of time to be built and will charge you a monthly maintenance fee on top of the initial construction costs.
All base facilities are linked, either directly or via other base facilities, to the Access Lift - in Apocalypse, because all bases are constructed in pre-exsting corridor layouts. You cannot dismantle a base facility that is in use. Up to now, there are no known methods or confirmed methods of destroying base modules through combat.
Security Stations are available from the start. When building up a new base, make a line of these defenses to separate the Vehicle Repair Bay and lift from the rest of the base. Keep those invaders slamming into those defenses!
Initial Base Facilities:
Researchable Base Facilities: