voom

[unixronin]

Up early today (0520) to get the driveway cleared so cymrullewes can get out to make it to Seabrook in time to pick up the paperwork she needs in time to meet with the client in Manchester at 0700.  Between six and eight inches of snow on the ground right now, and still snowing.  Gilford schools are delayed two hours at present, but snowscraper is on the job monitoring for updates.  There's some slush under the snow at the bottom of the driveway that mostly melted yesterday and didn't re-freeze overnight, but with fresh snow to help move it along, the snowblower copes.  It bogs a little when it hits the slush, then it digs in, spits it out and keeps on going.

The snowblower has something in common with Little Cat Z.  Or the contents of his hat, at any rate.  It goes VOOM.  The solid stream of snow blasting out of the discharge chute makes me think of a firefighting water monitor.

Which suddenly leads me to wonder, if it were practical, how good would such a stream of snow be at fire suppression?  One would think it'd suck more heat out of the fire than water, and might be better at smothering it because it'd tend to stick on contact (in the short moments before it melted).  But it'd probably be difficult to generate that kind of quantity of snow on demand in a dense enough stream, and I suspect the jet wouldn't carry as far as a jet of water does.

Comments

[metahacker.livejournal.com]

To knock down fires I was told you want high heat capacity (to reduce the temperature of the system below the point of combustion). IIRC snow is roughly 1/10th as dense as water, so you'd need >10x temperature difference between the burning material and the snow than you get with water. I think this isn't possible, just doing some quick calculations (say the fire is at 800K, water at 300K; snow can't be at -5000K...).

Now, really wet snow might cling better, and have a higher density, but I'm still not sure it is better than cold water.

[unixronin.livejournal.com]

IIRC snow is roughly 1/10th as dense as water, so you'd need >10x temperature difference between the burning material and the snow than you get with water.

No, you'd just need ten times the volume of snow. :)
(Somewhat less, actually, because the extra energy required to melt the snow gives it a higher heat capacity.)

[robbat2.livejournal.com]

I'm not sure how well it would work because of a side-effect that I've seen fire depts complain about: freezing-level weather causing the water on the fire to solidify and not get to the base of the fire.

[unixronin.livejournal.com]

Huh. That's not an effect I'd have ever expected....