diff --git a/lib/Slic3r/Extruder.pm b/lib/Slic3r/Extruder.pm
index c1ce91bc2..68536924c 100644
--- a/lib/Slic3r/Extruder.pm
+++ b/lib/Slic3r/Extruder.pm
@@ -307,7 +307,7 @@ sub _Gx {
     my $append_bridge_off = 0;
     if ($speed ne $self->last_speed) {
         if ($speed eq 'bridge') {
-            $gcode = "_BRIDGE_FAN_START\n$gcode";
+            $gcode = ";_BRIDGE_FAN_START\n$gcode";
         } elsif ($self->last_speed eq 'bridge') {
             $append_bridge_off = 1;
         }
@@ -325,7 +325,7 @@ sub _Gx {
     
     $gcode .= sprintf " ; %s", $comment if $comment && $Slic3r::gcode_comments;
     if ($append_bridge_off) {
-        $gcode .= "\n_BRIDGE_FAN_END";
+        $gcode .= "\n;_BRIDGE_FAN_END";
     }
     return "$gcode\n";
 }
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 5dcd65166..59a3568b3 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -629,9 +629,7 @@ sub export_gcode {
         }
         
         # go to layer
-        print $fh $extruder->change_layer($layer);
-        
-        my $layer_gcode = "";
+        my $layer_gcode = $extruder->change_layer($layer);
         $extruder->elapsed_time(0);
         
         # extrude skirts
@@ -701,10 +699,10 @@ sub export_gcode {
         
         # bridge fan speed
         if (!$Slic3r::cooling || $Slic3r::bridge_fan_speed == 0 || $layer->id < $Slic3r::disable_fan_first_layers) {
-            $layer_gcode =~ s/^_BRIDGE_FAN_(?:START|END)\n//gm;
+            $layer_gcode =~ s/^;_BRIDGE_FAN_(?:START|END)\n//gm;
         } else {
-            $layer_gcode =~ s/^_BRIDGE_FAN_START\n/ $extruder->set_fan($Slic3r::bridge_fan_speed, 1) /gmex;
-            $layer_gcode =~ s/^_BRIDGE_FAN_END\n/ $extruder->set_fan($fan_speed, 1) /gmex;
+            $layer_gcode =~ s/^;_BRIDGE_FAN_START\n/ $extruder->set_fan($Slic3r::bridge_fan_speed, 1) /gmex;
+            $layer_gcode =~ s/^;_BRIDGE_FAN_END\n/ $extruder->set_fan($fan_speed, 1) /gmex;
         }
         
         print $fh $layer_gcode;