Have a look at PT&P’s high temperature pipe supports (hot shoes)
Pipe Shields Inc., a division of PT&P, manufactured 215 heavy duty pre-insulated supports for a high temperature application in Oregon. They are 15″ L x 20″ W x 31″ H and are designed to accommodate 14″ – 20″ diameter pipes. The hot shoes have a calcium silicate insulation thickness of 2.5″- 3″. The base, clamps, nuts, jackets and bolts are all fabricated from hot dipped galvanized carbon steel and coated with red oxide paint. Standard Q.C. and dimensional tests were performed prior shipment.