Burner's exhaust pipe insulation were worn and burned.
Opened up the old ceramic fire wool.
Then, we inspected the internal pipe condition.
We sealed the flanges with high temp silicone and add in more bolts and nuts.
Next, we wrapped the exhaust with Isowool ceramic fibre blanket 1260 50mm thick.
Lastly, wrap a 0.7mm thick aluminum cladding.
The exhasut now have good layer of protection.

Materials used,
1. Isowool Cermaic Fibre Blankets 50mm x 600mm x 3600mm 
    Grade: 1260 130kg/m3
2. 0.7mm x 51kg aluminum sheet
3. Pan head self drilling screws
4. Thin galvanized wire
5. High Temperature silicone sealant.