diff --git a/include/DataStructures/Container/Queues/BinaryHeap.hpp b/include/DataStructures/Container/Queues/BinaryHeap.hpp
index d920c829..717915c0 100644
--- a/include/DataStructures/Container/Queues/BinaryHeap.hpp
+++ b/include/DataStructures/Container/Queues/BinaryHeap.hpp
@@ -1209,7 +1209,6 @@ class BinaryHeapLoopDifferentiation<HeapType const, ExecutionPolicy::parallel> {
 
 #else // OPENMP_AVAILABLE
 
-namespace internal {
 template<typename HeapType>
 class BinaryHeapLoopDifferentiation<HeapType, ExecutionPolicy::parallel>
     : public BinaryHeapLoopDifferentiation<HeapType, ExecutionPolicy::sequential> {