Originally Posted by
Water pilot
Not to say that building science is anywhere near perfect, the Grenfell Tower fire is a pretty good example of what happens when you don't test the materials that you apply on a large scale.
To my mind the materials testing (although there are still a lot of questions in that area) wasn't the biggest issue with Grenfell. The real problem was grafting new-standard-stuff onto old-standard-design without fully understanding how the old and new interact (in this sense it is very very similar to the MAX saga). Grenfell-style cladding is, and was, known to go up like a match, proven by testing in reality, it has done multiple times in Dubai - but people don't typically die in the fire, and the buildings stay mostly intact with little internal damage, "just" a re-clad needed. Modern skyscrapers are designed with extensive internal fire suppression systems, and typically multiple exit paths, refuge floors, etc. - all stuff Grenfell didn't have. Grenfell was designed to cope with fire the old fashioned way by fire-containment-cell. Over-cladding breaches that containment (IMO)
regardless of materials because there is always, always, an air gap by design, which is a chimney by any other name. Even if the actual cladding was completely non-flammable there would still be debris/rubbish/junk accumulating in the gap, fire-containment is thus breached.
We know, from testing in reality, that containment-cell design works, we know, from testing in reality, that ACM cladding design with modern fire suppression works. This does not mean we can assume that ACM cladding over containment-cell design will work, and it didn't (same goes for steel-cables and FBW on aircraft). Retrofitting cladding on the outside of buildings designed with fire-containment-cells should never ever be allowed, I cannot see how external cladding can possibly be done keeping
within the cell. The only option should be to upgrade the entire building to modern standards including full internal fire suppression - because the containment is gone.
Interestingly UK building standards are written to anticipate this sort of thing. A year or so before Grenfell I looked into a loft refurb/conversion, I was told by a building control inspector that because I was adding new accommodation space I would have to meet current regs. for exit routes and fire suppression, which with a single staircase and more than four floors meant I would have to retrofit sprinkler system and firedoors throughout the house (which made the project a non-starter).
So, where, you ask, was that building control inspector, or his London brethren, when they did the Grenfell refurb (which added extra accommodation floors as well as cladding, and definitely involved more than four floors and no sprinklers)? Well he wasn't involved, because the big guys get to do "self certification" on building projects (which brings us right back on topic again)...