diff --git a/src/meshTools/octree/treeBoundBox.C b/src/meshTools/octree/treeBoundBox.C
index e3972f3a26bcc814b58e3375d58de61878c050ee..1f79a35c3a4c090c1c01f2d1ccc227cbf3178206 100644
--- a/src/meshTools/octree/treeBoundBox.C
+++ b/src/meshTools/octree/treeBoundBox.C
@@ -617,13 +617,13 @@ Foam::label Foam::treeBoundBox::distanceCmp
 
 // * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
 
-bool operator==(const treeBoundBox& a, const treeBoundBox& b)
+bool Foam::operator==(const treeBoundBox& a, const treeBoundBox& b)
 {
     return (a.min() == b.min()) && (a.max() == b.max());
 }
 
 
-bool operator!=(const treeBoundBox& a, const treeBoundBox& b)
+bool Foam::operator!=(const treeBoundBox& a, const treeBoundBox& b)
 {
     return !(a == b);
 }