Best thing I have seen is the turnigy lipo bunker.
http://www.hobbyking.com/hobbyking/s...harge_box.html
Slow one is not a fan, but I use one at home, it controls any potential fire better than a sack, but it does vent the fumes, I'm sure the guy in Dave's 1st post would rather have had a house full of fumes over the fire.
Some will follow this with its faults (slow one) but sack or bunker I know which I trust I'm not sure if this bunker is ok for BRCA use, defo worth while for home use.
https://www.youtube.com/watch?v=rusH...e_gdata_player
The biggest failure of a lipo sack is the failure to put the lipo in fully and fully seal the Velcro.