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Comment by zw123456 | Hacker News Reader

I wonder if it would make a good fire retardant. The water would heat up and make steam and burst out along with some CO2 trapped in it.

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Drywall is used in fire safes for that reason. Drywall is made of gypsum, a mineral with water trapped inside its chemical structure. Heat releases that water, which turns into steam and cools the panel. Note that fire-rated drywall is usually glass fiber reinforced, to keep the panel together during a fire.

It wouldn't be as good as Aerogel [1] which is a similar silica nano-particle based structure. It contains air as opposed to water so conducts very little heat.

[1] http://www.aerogel.org/?p=1929

Sounds like Aerogel would be lighter, too.

Except that aerogel, classically, is incredibly unbelievably fragile.

There's now composites out there that are supposedly better though.

This also comes to mind:

https://en.wikipedia.org/wiki/Starlite

I suspect that would at least partly depend on how hazardous it is to humans, especially under high temperature/pressure or as an inhalation hazard. Is there an MSDS for dry water?

It might be similar to silica dust:

https://louisville.edu/micronano/files/documents/safety-data...

I'm not sure about any differences due to the grain size or the presence of the water. (And maybe something unusual would happen when the water inside each droplet boils due to proximity to the flame -- I don't know what would happen as the droplets rupture.)

A guy I know looked into this as part of his MS thesis:

https://repositories.lib.utexas.edu/handle/2152/28498

Reading the abstract, I don't know if he tested it as a fire retardant or suppressing agent, but that's obviously the idea. I think the challenge was more in making dry water on demand.

I work on an auto repair shop and was just thinking the same thing. We use a high pressure foam for fire suppression currently. The vendor says its a mix of soap, water, and co2. Only used it once but man is it messy!

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