3 ms·

The bricks contain polyethylene, but a large part, probably most of it, is sand. Also, it is not foam in enclosed spaces, but a full hard material. A non-flamm

by labawi 6y ago

The bricks contain polyethylene, but a large part, probably most of it, is sand. Also, it is not foam in enclosed spaces, but a full hard material. A non-flammable coating would perhaps be a layer of plaster or paint? I think you are seriously overestimating the flammability of the product. Have you seen rooms with vinyl floors, PVC windows, foam / fake leather couches? Each of those will burn more easily a viciously than the bricks. My concern would be with possible structural failure at high temperatures and some fires may be able to pass through walls of these bricks. However, I don't think they are building apartment buildings from these bricks.

robocat 6y ago
From article: “In his report to the public inquiry, Professor Luke Bisby said evidence ‘strongly supports’ the theory that the polyethylene material in the cladding was the primary cause of the fire's spread.” and “The ACM (aluminium composite material) product on Grenfell Tower incorporates a highly combustible polyethylene polymer filler which melts, drips, and flows at elevated temperature.”. I am not a materials engineer, but it looks to me that bricks with more than 10% of polyethylene are likely to be flammable in the case of a house fire. I don’t know whether the Grenfell tower cladding had filler, but it is common for the polyethylene core to be mixed with filler within the cladding to help protect against fire, for example the ALPOLIC A2 product mentioned in [1] has an image showing a table with: ALPOLIC fr: Combustible ingredients < 30%. < 13 MJ/kg ALPOLIC A2: Combustible ingredients < 10%. < 3 MJ/kg And [1] says “Its calorific value is given as something less than 13 MJ/kg, more than four times the value considered to be of ‘limited combustibility’ in the UK”. Above facts are why I think even a large percentage of sand might still leave flammable bricks (polyethylene is like solid petroleum, until it melts and behaves more like a liquid or wax with a viscosity depending on multiple factors). [1] http://theriveroflife.com/2018/02/08/grenfell-tower-is-the-core-of-acm-panels-a-filler-material/ http://theriveroflife.com/2018/02/08/grenfell-tower-is-the-c...
LegitShady 6y ago
PE has a melting point around 100-150c. In house fires, flashover (the point where fires become widespread because hot gasses created by smaller fires self ignite) are in the realm of 3-4x this (~500-600c). Your bricks would literally be loose sand by that point. You need space shuttle aerogel tiles not paint.
- labawi 6y ago
  I'm well aware a sustained fire will melt and burn the bricks. The question is how fast and how easy it is to ignite. Sand has a lot of thermal mass, so with some insulation against surface fires (PE surface is easy to ignite) - say a proper coat of paint, or maybe some plaster - a lone kindling would not ignite the bricks. A proper fire will, but then you should be running away anyhow. Still, if I were a firefighter, I would not approve of such building materials, unless the shoddy construction is well known, so noone dares go inside, mainly because it's likely to collapse and turn in to a bunch of hot burning goo. Luckily, they seem to use it for pavement.
  - LegitShady 6y ago
    > a lone kindling would not ignite the bricks again, far before a fire reaches a point where it's widespread the heat of the gasses created by a small fire are already 4x what these bricks can stand before the binder involves melt. So long before you're worried about thermal mass, there would be nothing holding these bricks together and you have a mass of loose sand and melted plastic. You could paint it with intumescent paint but I doubt it would be effective given the low melting temperature, and would probably end up costing as much or more as the brick.
    - labawi 6y ago
      I dare you to take a thick PE panel/plate, paint the surface with regular non-flammable interior paint (enough so you can't see through), and then light it with a match or a cigarette. Preferably in a vertical position through the painted side. If unconvinced, try the same with a piece of old sofa, fake leather or vinyl flooring (with or without paint).
      - LegitShady 6y ago
        I actually studied fire engineering, so rather than a dare, I've actually burned loaded concrete/steel beams, and connections in giant furnaces that get a lot hotter than your match to evaluate their fire performance. I don't think you're listening to what I'm saying about the common air temperature around small fires (auto-ignition of hot gasses at ~600°C is common) and the melting temperature of the binder in these bricks (150°C max). It's not about ignition of the PE, its about cohesion of the brick PE binder (and thus the sand) at higher temperatures. Your painting this brick that will lose cohesion will do exactly nothing for the performance of the brick. I dare you to think about it critically, instead of making useless dares that don't address what the other person is saying.

by labawi 6y ago

robocat 6y ago

From article: “In his report to the public inquiry, Professor Luke Bisby said evidence ‘strongly supports’ the theory that the polyethylene material in the cladding was the primary cause of the fire's spread.” and “The ACM (aluminium composite material) product on Grenfell Tower incorporates a highly combustible polyethylene polymer filler which melts, drips, and flows at elevated temperature.”. I am not a materials engineer, but it looks to me that bricks with more than 10% of polyethylene are likely to be flammable in the case of a house fire. I don’t know whether the Grenfell tower cladding had filler, but it is common for the polyethylene core to be mixed with filler within the cladding to help protect against fire, for example the ALPOLIC A2 product mentioned in [1] has an image showing a table with: ALPOLIC fr: Combustible ingredients < 30%. < 13 MJ/kg ALPOLIC A2: Combustible ingredients < 10%. < 3 MJ/kg And [1] says “Its calorific value is given as something less than 13 MJ/kg, more than four times the value considered to be of ‘limited combustibility’ in the UK”. Above facts are why I think even a large percentage of sand might still leave flammable bricks (polyethylene is like solid petroleum, until it melts and behaves more like a liquid or wax with a viscosity depending on multiple factors). [1] http://theriveroflife.com/2018/02/08/grenfell-tower-is-the-core-of-acm-panels-a-filler-material/ http://theriveroflife.com/2018/02/08/grenfell-tower-is-the-c...

LegitShady 6y ago

PE has a melting point around 100-150c. In house fires, flashover (the point where fires become widespread because hot gasses created by smaller fires self ignite) are in the realm of 3-4x this (~500-600c). Your bricks would literally be loose sand by that point. You need space shuttle aerogel tiles not paint.

labawi 6y ago
I'm well aware a sustained fire will melt and burn the bricks. The question is how fast and how easy it is to ignite. Sand has a lot of thermal mass, so with some insulation against surface fires (PE surface is easy to ignite) - say a proper coat of paint, or maybe some plaster - a lone kindling would not ignite the bricks. A proper fire will, but then you should be running away anyhow. Still, if I were a firefighter, I would not approve of such building materials, unless the shoddy construction is well known, so noone dares go inside, mainly because it's likely to collapse and turn in to a bunch of hot burning goo. Luckily, they seem to use it for pavement.
- LegitShady 6y ago
  > a lone kindling would not ignite the bricks again, far before a fire reaches a point where it's widespread the heat of the gasses created by a small fire are already 4x what these bricks can stand before the binder involves melt. So long before you're worried about thermal mass, there would be nothing holding these bricks together and you have a mass of loose sand and melted plastic. You could paint it with intumescent paint but I doubt it would be effective given the low melting temperature, and would probably end up costing as much or more as the brick.
  - labawi 6y ago
    I dare you to take a thick PE panel/plate, paint the surface with regular non-flammable interior paint (enough so you can't see through), and then light it with a match or a cigarette. Preferably in a vertical position through the painted side. If unconvinced, try the same with a piece of old sofa, fake leather or vinyl flooring (with or without paint).
    - LegitShady 6y ago
      I actually studied fire engineering, so rather than a dare, I've actually burned loaded concrete/steel beams, and connections in giant furnaces that get a lot hotter than your match to evaluate their fire performance. I don't think you're listening to what I'm saying about the common air temperature around small fires (auto-ignition of hot gasses at ~600°C is common) and the melting temperature of the binder in these bricks (150°C max). It's not about ignition of the PE, its about cohesion of the brick PE binder (and thus the sand) at higher temperatures. Your painting this brick that will lose cohesion will do exactly nothing for the performance of the brick. I dare you to think about it critically, instead of making useless dares that don't address what the other person is saying.