Any pointers to where a list of what requires repairs/can suffer failures and what cannot? And why does armour increase AFR/IFR?
AFR/IFR is depending on total tonnage/eng. space tonnage. So more armour means more size means more Failure, if you don't add more engineer spaces.
There are components that cannot break since they do not require maintenance. Crew quarters, cargo holds, bridge - basically most of the commercial components. That limits what can break on a ship when it fails the IFR roll.
When I remember right, in one of my 1. 7 Games a Crew Quarter of one survey ship suffers a failure. So I think on a military ship every System can fail. But I could remember it wrong.