4 ms·

I heard that fly ash can be radioactive - I hope these bricks are not. >The recipe incorporates large amounts of fly ash -- a fluffy, powdery residue of burned

by DTrejo 17y ago

I heard that fly ash can be radioactive - I hope these bricks are not. >The recipe incorporates large amounts of fly ash -- a fluffy, powdery residue of burned coal at electric plants, that can otherwise wind up as a troublesome pollutant.

stuff4ben 17y ago
A good pros/cons view of Fly Ash in concrete. http://findarticles.com/p/articles/mi_gx5204/is_2003/ai_n19124302/?tag=content;col1 http://findarticles.com/p/articles/mi_gx5204/is_2003/ai_n191... And if it is radioactive (which I haven't seen referenced anywhere) then we're screwed because FA is used everywhere.
jerf 17y ago
Everything is radioactive. It's a question of levels, not whether or not it is or is not radioactive. Popping "fly ash radioactive" into Google gave me http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html, "Radioactive Elements in Coal and Fly Ash: Abundance, Forms, and Environmental Significance", the most relevant sentences being: "Fly ash is commonly used as an additive to concrete building products, but the radioactivity of typical fly ash is not significantly different from that of more conventional concrete additives or other build-ing materials such as granite or red brick. One extreme calculation that assumed high proportions of fly-ash-rich concrete in a residence suggested a dose enhancement, compared to normal concrete, of 3 percent of the natural environmental radiation." As that says, there are other mildly radioactive materials already in use, with insignificant increases over natural environmental radiation. Everything is radioactive. Furthermore, when used in a brick, the only significant type of radioactivity that would matter is gamma rays, as alpha and beta radiation would largely be block by the brick itself, and, since you're likely to have drywall or something between you and the bricks, the drywall. (Which is way more than you need to block beta.) I'm not sure how much gamma rays there are in the uranium breakdown path, but it may not be as much as you'd think. Bonus link: http://www.keystonegranite.com/radiation.php http://www.keystonegranite.com/radiation.php ("Trace amounts of uranium are sometimes incorporated into materials used in construction. These include, but are not limited to concrete, brick, granite, and drywall.") Well, so much for the drywall shield. :)
- ars 17y ago
  There was a big hoopla recently about granite used for kitchen counters sometimes being radioactive.
  - lief79 17y ago
    Sure, most people hear radioactive, and think of Chernobyl, cancer, and Godzilla. In reality, radiation is everywhere, and it's a question of levels and risk. I doubt the radiation in bricks would compare to the exposure to radon in the typical house.
thwarted 17y ago
Heh, puts the "Chronic Low-Level Radiation Good for Us? Taiwan Housing Accident Suggests So" ( http://news.ycombinator.com/item?id=833662 http://news.ycombinator.com/item?id=833662 ) story from a few days ago in a new light.

by DTrejo 17y ago

stuff4ben 17y ago

A good pros/cons view of Fly Ash in concrete. http://findarticles.com/p/articles/mi_gx5204/is_2003/ai_n19124302/?tag=content;col1 http://findarticles.com/p/articles/mi_gx5204/is_2003/ai_n191... And if it is radioactive (which I haven't seen referenced anywhere) then we're screwed because FA is used everywhere.

jerf 17y ago

Everything is radioactive. It's a question of levels, not whether or not it is or is not radioactive. Popping "fly ash radioactive" into Google gave me http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html, "Radioactive Elements in Coal and Fly Ash: Abundance, Forms, and Environmental Significance", the most relevant sentences being: "Fly ash is commonly used as an additive to concrete building products, but the radioactivity of typical fly ash is not significantly different from that of more conventional concrete additives or other build-ing materials such as granite or red brick. One extreme calculation that assumed high proportions of fly-ash-rich concrete in a residence suggested a dose enhancement, compared to normal concrete, of 3 percent of the natural environmental radiation." As that says, there are other mildly radioactive materials already in use, with insignificant increases over natural environmental radiation. Everything is radioactive. Furthermore, when used in a brick, the only significant type of radioactivity that would matter is gamma rays, as alpha and beta radiation would largely be block by the brick itself, and, since you're likely to have drywall or something between you and the bricks, the drywall. (Which is way more than you need to block beta.) I'm not sure how much gamma rays there are in the uranium breakdown path, but it may not be as much as you'd think. Bonus link: http://www.keystonegranite.com/radiation.php http://www.keystonegranite.com/radiation.php ("Trace amounts of uranium are sometimes incorporated into materials used in construction. These include, but are not limited to concrete, brick, granite, and drywall.") Well, so much for the drywall shield. :)

ars 17y ago
There was a big hoopla recently about granite used for kitchen counters sometimes being radioactive.
- lief79 17y ago
  Sure, most people hear radioactive, and think of Chernobyl, cancer, and Godzilla. In reality, radiation is everywhere, and it's a question of levels and risk. I doubt the radiation in bricks would compare to the exposure to radon in the typical house.

thwarted 17y ago

Heh, puts the "Chronic Low-Level Radiation Good for Us? Taiwan Housing Accident Suggests So" ( http://news.ycombinator.com/item?id=833662 http://news.ycombinator.com/item?id=833662 ) story from a few days ago in a new light.