7 ms·

What is burnt may never burn. See Shou Sugi Ban (焼杉板).

• benj111 8y ago
  Charcoal? Coke?
  • vidarh 8y ago
    Production of charcoal and coke both depend on not fully burning the wood or coal, by constraining the oxygen supply, but by heating/baking it to reduce the water content and volatiles. Older processes burn more of the material, in part to help produce the heat, while newer processes try to fuel it mostly of the off-gassing. But the comment above is referring to a specific treatment of wood by charring the outer layer to make it act as a fire retardant.
    • benj111 8y ago
      My understanding of Shou Sugi Ban is basically to create a charcoal layer on the wood, so its unclear to me how that would prevent it burning, as charcoal is designed to burn. At best I can see it increasing the ignition temperature.
      • chipsa 8y ago
        It's not fully charcoal (fully carbonized). Wood is mostly two compounds: cellulose and lignin. They undergo thermal decomposition at different temperatures. By partially burning the exterior, you decompose the cellulose, and when you attempt to set it on fire again, it's harder to light, because you no longer have the cellulose decomposition to provide fuel, but have to get to a higher temperature for the lignin to decompose. It's charred, but not charcoal. And yes, mostly it just makes the ignition temperature go up. But that's half the battle for fireproofing. You're mostly not trying to stop it from ever burning, but giving people enough time to evacuate, or the firefighters to put it out with water.