I think the most important battle is educating the customer that the carpets need cleaning frequently. The more frequently they are cleaned, the lighter system you need to clean them and the less risk is involved.
Presuming the carpets aren't heavily soiled, I'd personally use a rotary system for speed and lack of downtime, being as we're talking about corridors that are in use 24/7.
If they are to be extracted, you just need to avoid getting the backing wet. Reduced FLOW rather than psi is the key, but obviously with most machines turning down the pressur results in less flow. If your vacuum performance stays the same but your flow rate is lower, you're running at a higher vacuum-to-flow ratio so therefore you stand less chance of overwetting. In short, if your machine (I presume you're running a portable) has a flow or pressure regulator, back it off a little lower than you'd normally use for something like tufted carpet.
If it's cleaned VERY often it may even be possible to keep maintained with a VLM system like host or envirodri, or any other compound used with a CRB machine. It's probably need a bloody good extraction clean once a year though, to get all that sawdust out
