Has anyone tried this for their heat riser insulation?

Up to 5" diameter - http://www.vermiculitecoated.com/high-temperature-heat-resistant-thermal-insulation-sleeve-tape-rope-fabric-firesleeve.html

1500°F / 815°C: Braided Vermiculite Coated Fiberglass Sleeve: Premium
Grade. Very High Temperature & Heat Resistant
FlameShield™ braided fiberglass sleeve with
specialty coating of Vermiculite.
 Available in thin wall (1/16 in. / 1.6mm.) and
thick wall (1/8 in. / 3.18mm.).
 1500°F / 815°C continuous exposure with
excursion to 2000°F / 1093°C.
1500°F / 815°C continuous rating, high insulation value & excellent personnel protection
The Vermiculite coating adds abrasion resistance and higher temperature capabilities which makes this sleeve a good
insulator for hose, cable and copper or aluminum tubing.

Dave Jersey: This is meant more for protection against accidental contact, think about the Internal Combustion Engine Exhaust, at 1500 f a mechanic can brush up against it
with little danger of serious burns ! It needs to survive higher temperatures to continue to function as a heat shield or barrier ! I personally doubt it would hold up in a R.M.H.
Heat Riser, and the largest size 5'', would make a marginally performing system due to friction loses in the laminar flow and turbulence !

I expect that it has been tried as a gasket material to help seal the type of 55 gal drums with removable tops, that should be a safe use with a wide enough heat range spread.

What we are looking for is something that will do a better job of resisting the transfer of heat energy though itself until the Temperatures are closer to 2500 - 3000 degrees f,
our combustion chamber should be glowing red hot and a small piece of dry wood dropped into the feed hole bursts into flame - a ceramic blanket material - Pricey!

For the Good of the Craft, as always, your comments and questions are solicited and Welcome, Think like fire, flow like /gas, PYRO - Logically Big AL!

Could you not use ceramic insulation? it comes in many thickness and grades and is used to protect kilns will last for years and is rated for constant use.