Re: "scientific testing" of safety is done by the manufacturing companies
For Grenfell Tower, an architect signed off on the fire safety without even checking. They stuck in some words copied from a computer program, and signed it, since "that's what everyone did".
They were not prosecuted.
If we actually wanted safe buildings, the best and easiest way to do that would have been to throw him in prison for 20 years for fraud and manslaughter. And then go back through building applications and throw lots of other people in prison for a month each for fraudulent statements. That would have made architects actually check the buildings are safe before signing off.