Fire Resistant Tarp For... a Fire!

[begleysm]

Hey guys,

I've been thinking about carrying an extra tarp to provide a shelter for my fire in rainy environments.

My 1st thought was just to get another WL Tadpole/WB Edge/MacCat Std and pitch it over my fire location hoping I put it high enough to not catch sparks.

Then I started googling for Fire Resistant Tarps. The only thing I found was this:
http://www.bushcraftoutfitters.com/M...T-multicam.htm
It is 5'x7', rectangle, and weighs 16 oz. Not too bad.

Here is a youtube video comparing its fire retardant properties against a urethane tarp (which should be better than a silnylon tarp I believe)
http://www.youtube.com/watch?v=HgUS9lwn0_E

Anyone have any thoughts on the subject of material?

Also, anyone have any thoughts on the shape of the tarp for this application (just to have a fire under and sit under)?

Thanks,
Sean