Say what you will about american safety regulations in general, but speaking from an architectural experience, our fire codes are actually a bit more strict than in most European countries, mostly due to several tragic early 20th century events.
If this building was properly compliant. The fire should have been contained to the flat the fire started in. I live in a flat block of 4 flats, 2 ground floor and 2 above, and even this will contain fires to the flat it occurs in, flats in every direction can be safely occupied during a fire in the others (although i'd probably do a runner despite that knowledge).
This should have been true for Grenfell, especially considering it was a concrete giant, and concrete is inherently good at containing fires regardless of regulations.
However it was a warm night and many flats would have had their windows open, security isn't a concern for having your windows wide open when you're 50 foot in the air. It's also reported that the fridge 'exploded', this could mean a few things considering peoples opinion. on what exploding is, however a modern fridge that uses the new style environmentally friendly gases can explode with enough ferocity to blow out windows if it was near to them, faulty fridges are fairly common occurence throughout the world and this has been proven many times. So wether the window was open to start with or it was opened through force, it almost certainly spread externally, then through open windows until the fire gained enough ferocity to burn out the windows itself.
Chances are, the building itself was structurally sound and met fire regulations, and the only reason this occured was due to the cladding, which may actually have been banned for UK use anyway for a building of that height (if not entirely), so don't be too sure to blame the safety regulations, chances are they were entirely, possibly willfully, ignored here.