Not being able to open on safety grounds is a bit of a joke when you look at how unsafe other teams grounds are.
There's no way the ground in it's current condition is less safe than Selhurst Park, they aren't being judged on the same criteria imo.
It's the same for all building work. New builds have to 100% be to the current codes, any renovation work isn't unless you change it's use (business to residential etc)