COLVENT Flam 180 TG is a SBS-modified bitumen base ply for use in approved multi-ply membrane and flashing assemblies. The ribbon strips are arranged in a pattern to vent vapor pressure between the substrate and the COLVENT Flam 180 TG. The topside and underside are surfaced with polyolefin burn-off film to optimize heat welding. COLVENT Flam 180 TG is composed of a proprietary formulation of elastomeric styrene-butadiene-styrene (SBS) polymer modified bitumen in combination with partially adhered ribbons and is reinforced with a tough, dimensionally stable nonwoven polyester mat.