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Comment by jstalin | Hacker News Reader

Maybe someone in the UK can answer this, but how on earth are fire sprinklers not required?

Originally the tower was built out of concrete & the outer skin of the building was glass, steel (windows & frames) & concrete. The safety case for the building was that no fire could escape a single unit, or worst case a single floor as everything in-between the flats in the building was completely non-combustible. Hence the advice to stay in place until the fire service had put any fire that happened to start in the block.

Originally it was a safe building, even without sprinklers: there have been many fires (inevitably) over the years in similar buildings which have never spread, because it was impossible for them to do so. Sprinkler systems would have made them safer & perhaps saved individual lives in the past but at no time were entire buildings at risk because of the lack of sprinkler systems, because it wasn’t possible for them to burn.

Unfortunately, covering the building in flammable insulation (!) and even more flammable rain cladding (!!) completely broke this safety case, turning the building into a death trap.

The tower block wasn't originally built with the cladding that burnt.

The idea was that the tower is almost all concrete, a fire on any one floor shouldn't spread as there is little to burn. The problem is that later modifications to the heating system and the addition of the cladding have changed the design a lot.

Fwiw regulations actually have been getting more conservative on this. There was more confidence in the 1970s (when this tower was built) that modern concrete construction didn't require sprinklers. With the core construction material itself not flammable, and serving as fireproof separation between units, fires were supposed to be contained by design, with spread unit-to-unit throughout the building (especially so rapidly that it'd happen before fire services could arrive) not being possible due to passive suppression, and therefore not in need of active suppression. Which as you say may even have been true with the original design prior to interior ducting and exterior cladding changes.

In any case, in the past 10 years the consensus has been changing towards it being prudent to just always require sprinklers in high-rise towers. Scotland began requiring them in 2005, and England in 2007, but neither law is retroactive.

From what I understand the apartments were meant to be "self contained" so in the event of a fire it would be contained long enough for the fire service to respond. It spread from the outside cladding

Buildings in the UK usually implement passive fire protection (making sure that fires can't spread easily and that they get contained to small areas of the structure) rather than active fire protection, which is things like sprinklers. They're both pretty effective methods. However, the combustible cladding made sure the fire could spread, rendering the fire protections of the building irrelevant :(

A working fire sprinkler system would have slowed down fire incursion and would have significantly reduced loss of life; as sprinklers have in many other high-rise fires involving flammable cladding. However, even an external cladding fire is dangerous, as burning plastics generate extremely toxic gases: hydrogen cyanide and carbon monoxide.

They are required nowadays, but weren't back in the 1970s when the tower block was built. I don't know exactly when the regulations changed, but existing buildings were not required to retro-fit them. There have been several calls to do so, not just after this fire, but after several previous ones too.

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