This non-foil-faced insulation is not UL Listed for use with chimney liners, but it is great when you need only small pieces for stuffing into nooks and crannies.
Non-Foil-Face FlexWrap can also seal the space between an insert shroud and the fireplace facing, or between frames of glass doors and the fireplace facing. Remember: Non-Foil-Face FlexWrap is not UL Listed for relining.