7-9 PSID is about right for transport aircraft. The 51000 foot Lears, etc. have PSID's above 10.0.
The best illustration I have heard to describe the forces involved is aircraft pressure vessels is as follows: The folks who design nuclear weapons consider the ring of destruction for (non-hardened) structures to be the .5 PSID overpressure ring surrounding the blast. We are running with differentials up to 20X that in our aircraft. That is why big people/things can go through small holes with a rapid D.