Graphene nanoplatelets (GNP) are currently mass-produced by mechanical exfoliation of graphite, however, Flash Joule Heating (FJH) is a relatively sustainable, cost effective, and efficient alternative. In this work, the reinforcing abilities of industrially produced Flash Graphene (FG) in flexible polyurethane foam (FPUF) are evaluated. Three types of FG with different structure and morphology are characterized and used to produce FPUF composites. A composite containing commercial, exfoliated GNP was also prepared for comparison. It was shown that 0.025 wt.% FG improved the thermal expansion coefficient of FPUF by 47%. FG composites also demonstrated higher sound absorption at low frequency relative to neat FPUF. The tensile strength and compressive modulus of all composites also increased by 16-26% and 33-37% respectively. Furthermore, FPUF reinforced with FG showed similar or enhanced properties compared to the GNP composite. Overall, FG improved thermal and acoustic performance of FPUF without deteriorating the mechanical properties. This supports the use of FG as a sustainable, low-cost alternative to exfoliated or CVD-grown GNP in porous polymer composites.