Barrier around flue pipe

Would anyone recommend a barrier between the insulation and this furnace flue? The insulation does not support combustion but it will char with direct heat. I tested it outside.

Yes, it an insulation dam is required around here.

How hot did you get it?..and for how long? I’d be careful making these type of statements.

Though treated with a fire retardant, it is not fire proof and some testing shows that the retardant looses effectiveness with time.


Thanks! I did not make that statement in the report.

Around cellulose, definitely.