DKMA......as resident Structural Engineer, I can appreciate what they are saying about the weight on the floor, however if it's a newish hospital, it will have been designed for much higher loadings than those typically recommended and should, in my professional opinion, be strong enough to take a pool roughly 1.2m diameter, filled up to a depth of about 0.55m. The hygeine shouldn't be an issue if you were to use a liner as they come, I believe, in sterile packs.
You could allways ask them what load the floor has been designed for and I'll do you a calculation to prove it'll be OK!!
Sorry, I'll take my anorak and hard hat off now