Perhaps because the earlier tests only required them to be resistant to external fires and these panels were fitted with an airgap between the building and panel and the fire attacked them from their vulnerable side?
So the previous tests, if that was the case were a fudge at best to permit the use of inadequate and cheaper panels.
And should have carried the caveat that there should not be an air gap between the panel and the building.
Sorry but as someone who worked in the design department of a boiler maker, I think heads should roll, including heads at hotpoint.
And in particular whoever they were, the so called designers who thought replacing an inert gas with isobutane .
And then to cover the back of the freezer with an inflammable panel because it's cheaper?
The company should face massive fines and lose its trading licence.
And isobutane banned as soon as a replacement found.
The should-er squad are always quick to appear after such incidents as the Grenfell tower tragedy. Should-er done this, should-er done that etc ect.
The situation is such that we can't protect everyone against every conceivable danger all of the time. It's a case of providing protection against an event, balanced with the probability of that event occurring. For example, a meteorite hit on a tower block could be catastrophic and cause the deaths of thousands of people. We could build in anti-meteorite protection to mitigate the consequences of such an event, but we choose not to. We choose not to on the basis of cost versus the likelihood of such a thing happening.
The same principle will have been applied to the Grenfell tower block. The panels will have been deemed to provide sufficient fire protection against an external ignition source such as a bin fire or car fire. I suspect that no one would have conceived of a situation whereby the ignition source would be applied to the reverse side of the panel. A rather unusual combination of circumstances, with a very low probability of all coming together, have conspired to bring about this terrible incident. Like most disasters, it is never one factor alone which causes it. In this case, we think it was a faulty fridge, AND a path for the fire to breach the fabric of the building, AND an air gap, AND inadequate fire resistance on the reverse of the panel, AND insufficient fire early warning, AND incorrect escape procedures. I've probably missed other factors, but this is just to give you an idea.
Each AND is a probability multiplier as well. So if two events carry a 1 in 1000 probability of occurring and rely on each other to bring about a failing, the overall probability of failure will be 1 in 1 million.
Grenfell tower is an unfortunate tragedy caused by a series of events, just like an airliner crash or similar. There will be a cause or weak link in the chain of events identified and measures will be taken to reduce the probability of a second similar incident. What is not acceptable is for a clown such as John McDonald to use words like "murdered" when talking about those who died in the blaze. This idiotic and contemptible ruse is not helpful and McDonald's only interest in Grenfell tower is to whip up a phoney class war in order to serve his own pathetic purposes.