-- https://scriptblox.com/script/Universal-Script-Fire-all-12970

function fyr(dd)
    for i,v in next,dd:children''do
        if(v:IsA'BasePart')then
            f=Instance.new('Fire',v);
            f.Size=25;
            f.Heat=19;
        end;
        if #(v:GetChildren())>0 then
            fyr(v) 
        end
    end
end

fyr(game.Workspace)