Smoke Density Characteristics and Smoke Reduction Effect of Medium-Density Fiberboard According to Surface Finish Type and Substrate Thickness

This study investigated the smoke density characteristics and shielding effect of surface finishes on medium density fiberboard (MDF)-based plywood to mitigate fire hazards related to reduced visibility and toxic gas exposure. Using the ASTM E662 test method, we evaluated the specific optical densities (Ds) of five surface finishes and three substrate thicknesses. The experimental results revealed that bare MDF produced the highest smoke density, reaching Ds values of up to 604, significantly exceeding fire safety limits. By contrast, finished panels produced less smoke, indicating that surface finishes serve as a “thermal shielding barrier” that delays substrate decomposition. Among the finishes, low-pressure melamine (LPM) and paper demonstrated stable and low smoke densities, whereas the polyvinyl chloride film and veneer approached the regulatory limit of Ds 400 at 18 mm. Optimizing these combinations was essential for reliable flame-retardant performance.