diff --git a/src/blockforest/BlockForest.cpp b/src/blockforest/BlockForest.cpp
index 70b1fdaf4d4ef2521d81a1a977032376cddad65d..50ebc8c27db75b4f309cec7ef6cebb9620c0e0d1 100644
--- a/src/blockforest/BlockForest.cpp
+++ b/src/blockforest/BlockForest.cpp
@@ -2844,7 +2844,7 @@ void BlockForest::saveToFile( const std::string & filename, FileIOMode fileIOMod
                                                                     "\n- block AABB = " << block->second->getAABB() );
             //Elementwise OR of all elements
             for (uint_t i = 0; i < suidBoolVec.size(); ++i) {
-               suidBoolVec[i] = suidBoolVec[i] | suidMap.find( *suid )->second[i];
+               suidBoolVec[i] = suidBoolVec[i] || suidMap.find( *suid )->second[i];
             }
          }
 
diff --git a/src/blockforest/SetupBlockForest.cpp b/src/blockforest/SetupBlockForest.cpp
index 449e8bea3d7b7b8d110d1b41de3d37a9ff0ff01b..4bd6046190047bec99baacc044f4ec252f6917dc 100644
--- a/src/blockforest/SetupBlockForest.cpp
+++ b/src/blockforest/SetupBlockForest.cpp
@@ -1783,7 +1783,7 @@ void SetupBlockForest::saveToFile( const char* const filename ) const {
                   WALBERLA_ASSERT( suidMap.find( *suid ) != suidMap.end() );
                   //Elementwise OR of all elements
                   for (uint_t k = 0;k  < suidBoolVec.size(); ++k) {
-                     suidBoolVec[k] = suidBoolVec[k] | suidMap.find( *suid )->second[k];
+                     suidBoolVec[k] = suidBoolVec[k] || suidMap.find( *suid )->second[k];
                   }
                }