Fire-rated doors are heavy, sturdy barriers designed to withstand intense heat and slow the spread of flames between rooms or sections of a building. They often have intumescent seals that expand when heated, blocking gaps, and are tested to hold for a specific time like 20, 45, or 90 minutes. These doors are common in hotels, offices, and apartment complexes, usually kept closed by self-closing hinges or automatic release mechanisms triggered by a fire alarm. They look similar to regular doors… fire-rated doors