4 ms·

My best friend in high school lost his house to a fire in the mountains of CO. The house was made out of clays and other highly fire resistant materials, to the

My best friend in high school lost his house to a fire in the mountains of CO. The house was made out of clays and other highly fire resistant materials, to the point it was designated the safe house for the fire crew of the area... when the four mile canyon fire swept through it was so hot it even melted all the metals like copper and steel. There was nothing left. I'm sure there are lots of ways to build houses to resist fire more, and we should be doing that, but "basically impervious" is an overstatement.

thaumasiotes 8y ago
> The house was made out of clays > when the four mile canyon fire swept through it was so hot it even melted all the metals like copper and steel. There was nothing left. But exposing clay to really hot fire just hardens it into fired clay. Hence the term. What happened there?
- zhengyi13 8y ago
  Fire resistance would be orthogonal to structural stability, I expect. If the steel beams melt, and they're what's holding up the clay, clay/structure can certainly collapse, even if you can still say nothing burned, as such.
  - deleted 8y ago
    [deleted]
- chrismorgan 8y ago
  FYI, if you expose clay to really really hot fire, it still melts. A mere 4,000°C will even melt everything in https://en.wikipedia.org/wiki/Ultra-high-temperature_ceramics https://en.wikipedia.org/wiki/Ultra-high-temperature_ceramic.... I have no real concept of the sorts of heats involved in fires like the one described above. But even if the clay isn’t melting, it’s fun to know that ceramics aren’t magical non-melting, non-burning things—they just require unusually much, typically impractically much, heat to achieve it.
  - derefr 8y ago
    It surprises me to learn that there are wildfires on the surface of the Earth that get hotter than a rocket nose-cone experiencing re-entry.
  - givehimagun 8y ago
    Looks like wildfires get up to about 1,200°C when really hot. https://nhmu.utah.edu/sites/default/files/attachments/Wildfire%20FAQs.pdf https://nhmu.utah.edu/sites/default/files/attachments/Wildfi...
londons_explore 8y ago
Even in stone/brick houses, they normally still have wooden roof beams. Typically embers set things like guttering and dry leaves in guttering on fire, and that then spreads through vents in the rafters into the rest of the building. A fire suppression water spray to keep the roof wet would probably save most brick buildings. Most fires burn out within half an hour or so, so one wouldn't even need too big a supply of water.
brownbat 8y ago
I'm very sorry to hear that, that's got to be a devastating experience to watch someone you know go through that. Basically impervious was an overstatement for emphasis, you're right. I was trying to draw a stark contrast with the sometimes thoughtless status quo, but I should have been more precise. And to be fair that crown fire study was just looking at thermal ignition, which isn't the whole picture. The strategies to prevent spread through embers are more complex and sometimes not possible in all areas -- vegetation control, standoff zones, irrigation... Still, as I think we both agree, much more can and should be done.

thaumasiotes 8y ago

> The house was made out of clays > when the four mile canyon fire swept through it was so hot it even melted all the metals like copper and steel. There was nothing left. But exposing clay to really hot fire just hardens it into fired clay. Hence the term. What happened there?

zhengyi13 8y ago
Fire resistance would be orthogonal to structural stability, I expect. If the steel beams melt, and they're what's holding up the clay, clay/structure can certainly collapse, even if you can still say nothing burned, as such.
- deleted 8y ago
  [deleted]
chrismorgan 8y ago
FYI, if you expose clay to really really hot fire, it still melts. A mere 4,000°C will even melt everything in https://en.wikipedia.org/wiki/Ultra-high-temperature_ceramics https://en.wikipedia.org/wiki/Ultra-high-temperature_ceramic.... I have no real concept of the sorts of heats involved in fires like the one described above. But even if the clay isn’t melting, it’s fun to know that ceramics aren’t magical non-melting, non-burning things—they just require unusually much, typically impractically much, heat to achieve it.
- derefr 8y ago
  It surprises me to learn that there are wildfires on the surface of the Earth that get hotter than a rocket nose-cone experiencing re-entry.
- givehimagun 8y ago
  Looks like wildfires get up to about 1,200°C when really hot. https://nhmu.utah.edu/sites/default/files/attachments/Wildfire%20FAQs.pdf https://nhmu.utah.edu/sites/default/files/attachments/Wildfi...

londons_explore 8y ago

Even in stone/brick houses, they normally still have wooden roof beams. Typically embers set things like guttering and dry leaves in guttering on fire, and that then spreads through vents in the rafters into the rest of the building. A fire suppression water spray to keep the roof wet would probably save most brick buildings. Most fires burn out within half an hour or so, so one wouldn't even need too big a supply of water.

brownbat 8y ago

I'm very sorry to hear that, that's got to be a devastating experience to watch someone you know go through that. Basically impervious was an overstatement for emphasis, you're right. I was trying to draw a stark contrast with the sometimes thoughtless status quo, but I should have been more precise. And to be fair that crown fire study was just looking at thermal ignition, which isn't the whole picture. The strategies to prevent spread through embers are more complex and sometimes not possible in all areas -- vegetation control, standoff zones, irrigation... Still, as I think we both agree, much more can and should be done.