Boom

[gridlore]

A hand grenade was found Monday on 19th Avenue near a Shell station at Santiago.

That;s about two blocks from where we used to live, but that's not why I'm posting this. This is (from the story):

Police diverted traffic from several directions and evacuated people from the immediate area before detonating the grenade about 2 p.m., Tully said.

A hand grenade has a lethal radius of about 4 meters. Beyond that, the shrapnel density drops off quickly. (figure the surface area of sphere.. the intact notched-wire fragmentation portion of the device is about 5cm across before it explodes.) Add in the fact that the shrapnel is not very aerodynamic, and you can be a few dozen feet from a grenade and escape harm. The biggest danger is concussion, and that isn't that bad. (about 5kg of C-4) There isn't a hand grenade on Earth that will lift a man off his feet, even if he's standing on it.

Which makes the evacuation bit a little funny. Were they going door to door making people leave homes? How far down did the traffic diversion begin? I think maybe they over-reacted just a little too much.

Comments

[isomeme.livejournal.com]

There are times when overreacting is prudent. First, herding people at least several hundred feet away from the danger space reduces the chance of (e.g.) a fast bicyclist or unnoticed child zipping right in at the last second and catching a fragment. Second, people get panicky when things go boom in a residential neighborhood, so it's good policy to do it without a lot of spectators.

What it really comes down to is CYA, though. You and I both know the weird tricks ballistics can play. If a wire fragment ends up flying 100 feet and putting out somebody's eye -- certainly not beyond the bounds of possibility -- do you want to be the SFPD field commander who decided to let the crowd stay that close to the grenade?

For clarification....

[jarlsberg71.livejournal.com]

(about 5kg of C-4)

I think 11 lbs of C-4 would be a much bigger bang... and also a VERY heavy hand-grenade.. I couldn't throw an 11 pound bowling ball very far.... And I think it might lift me off of what *was* my feet.

I wonder if I can get the explosive force of c4 from googling? I shouldn't since I'm in C class. hmm seems appropriate C... C-4...

Re: For clarification....

[gridlore.livejournal.com]

Argh. it ate the period. .5kg, for a really big grenade.

The M67, which I trained with, has .18kg of C-4.

http://www.fas.org/man/dod-101/sys/land/m67.htm

Threw about ten live grenades during my service. Real big fun.

Re: For clarification....

[fearsclave.livejournal.com]

Heh: a 5-kg hand grenade would likely be in the running for Most Useless Infantry Weapon of All Time, although I suppose that if you could roll it downhill at the enemy...

Re: For clarification....

[jarlsberg71.livejournal.com]

useless yeah, but think of the arms on the guys who'd have to throw them! :)

Ok well atleast that's the reason why *I'm* not allowed in the military....