Nowadays, in many fields such as transportation, the demand for materials which can act as fire barrier is in constant increase. To create such fire barrier, different pathways can be considered. The standard approach consists in changing the chemistry of the material by incorporating flame retardant agents to improve its fire protective performances. But the development of novel chemistries remains challenging. In this work, a new way of thinking came up. Instead of changing the material formulation, the layout of materials is tested to reach the optimized fire protection. To do this, thermocompression, which is a classical polymer shaping process, does not easily allow designing sophisticated shapes without using a complex mold, on the contrary to 3D printing, which is a very flexible technique. Among all 3D printing techniques, Fused Deposition Modeling (FDM) is of high potential for product manufacturing, and quite low cost, but the range of filaments commercially available is limited. However, in some specific 3D printing processes, no filaments are necessary, which allow to investigate many polymeric matrices with no commercial limitation. This is of high interest for the design of flame retardant materials, but literature is scarce in that field. Using this innovative approach, different designs of flame retarded materials have been investigated to highlight the benefit of this new processing technology. Firstly, homogenously flame retarded samples have been considered (bulk treatment) and the comparison between the performances of samples prepared by thermocompression and 3D printing has been carried out based on four different Ethylene-vinylacetate copolymer (EVA) formulations containing aluminum trihydroxide (ATH) (which has an endothermic flame retardant action) or expandable graphite (EG) (which has a physical mode of action). Then, new concepts of multi-materials have been thought out to optimize the fire protection by changing the design by decreasing the percentage of polymer, and adding polymer just where it is needed. Based on this new design, new materials: biphasic materials, were elaborated with liquid phase. A full characterization of the thermal protective properties of these novel 3D designs will be presented. This work is a pioneering innovative study (based on the scarce data in literature) for exploring the feasibility of using FDM technology to design new flame retarded materials, offering the way to make safer materials at low cost.