A polymeric fiber liner insulation includes of a resilient, insulation blanket core of randomly oriented entangled fibers with between 60% and 90% by weight of the fibers being standard polymeric fibers and/or flame retardant polymeric fibers and between 10% and 40% by weight of the fibers being polymeric lofting and bonding fibers. The first major surface the liner insulation has a low porosity or air and/or liquid impervious surface layer. The surface layer is formed by melting and consolidating fibers at and adjacent the first major surface of the blanket core or by coating the first major surface of the blanket core with a polymeric coating. The liner insulation exhibits a flame spread/smoke developed index of ≦ 25/50.