diff --git a/test_problems/cathermo/DH_graph_1/DH_graph_1.cpp b/test_problems/cathermo/DH_graph_1/DH_graph_1.cpp
index 1055a6a0e..91f84f657 100644
--- a/test_problems/cathermo/DH_graph_1/DH_graph_1.cpp
+++ b/test_problems/cathermo/DH_graph_1/DH_graph_1.cpp
@@ -20,6 +20,7 @@
 #include "cantera/kernel/thermo/DebyeHuckel.h"
 #endif
 
+using namespace std;
 using namespace Cantera;
 
 class fileLog: public Logger {
diff --git a/test_problems/cathermo/HMW_graph_CpvT/HMW_graph_CpvT.cpp b/test_problems/cathermo/HMW_graph_CpvT/HMW_graph_CpvT.cpp
index dd6121a7d..4b2a13ed7 100755
--- a/test_problems/cathermo/HMW_graph_CpvT/HMW_graph_CpvT.cpp
+++ b/test_problems/cathermo/HMW_graph_CpvT/HMW_graph_CpvT.cpp
@@ -27,6 +27,7 @@
 #include "importCTML.h"
 #endif
 
+using namespace std;
 using namespace Cantera;
 
 class fileLog: public Logger {
diff --git a/test_problems/cathermo/HMW_graph_GvI/HMW_graph_GvI.cpp b/test_problems/cathermo/HMW_graph_GvI/HMW_graph_GvI.cpp
index 744cdcb11..b52d8c9c4 100644
--- a/test_problems/cathermo/HMW_graph_GvI/HMW_graph_GvI.cpp
+++ b/test_problems/cathermo/HMW_graph_GvI/HMW_graph_GvI.cpp
@@ -22,6 +22,7 @@
 #include "HMWSoln.h"
 #endif
 
+using namespace std;
 using namespace Cantera;
 
 class fileLog: public Logger {
diff --git a/test_problems/cathermo/HMW_graph_HvT/HMW_graph_HvT.cpp b/test_problems/cathermo/HMW_graph_HvT/HMW_graph_HvT.cpp
index d1edf268d..c3c63a9ef 100644
--- a/test_problems/cathermo/HMW_graph_HvT/HMW_graph_HvT.cpp
+++ b/test_problems/cathermo/HMW_graph_HvT/HMW_graph_HvT.cpp
@@ -22,6 +22,7 @@
 #include "cantera/thermo.h"
 #endif
 
+using namespace std;
 using namespace Cantera;
 
 class fileLog: public Logger {
diff --git a/test_problems/cathermo/HMW_graph_VvT/HMW_graph_VvT.cpp b/test_problems/cathermo/HMW_graph_VvT/HMW_graph_VvT.cpp
index 05857bf3c..c4de9880b 100755
--- a/test_problems/cathermo/HMW_graph_VvT/HMW_graph_VvT.cpp
+++ b/test_problems/cathermo/HMW_graph_VvT/HMW_graph_VvT.cpp
@@ -28,6 +28,8 @@
 #include "importCTML.h"
 
 #endif
+
+using namespace std;
 using namespace Cantera;
 
 class fileLog: public Logger {
diff --git a/test_problems/cathermo/HMW_test_1/HMW_test_1.cpp b/test_problems/cathermo/HMW_test_1/HMW_test_1.cpp
index 8087171f0..5e088e596 100644
--- a/test_problems/cathermo/HMW_test_1/HMW_test_1.cpp
+++ b/test_problems/cathermo/HMW_test_1/HMW_test_1.cpp
@@ -15,6 +15,7 @@
 #include "HMWSoln.h"
 #endif
 
+using namespace std;
 using namespace Cantera;
 
 int CHECK_DEBUG_MODE = 0;
diff --git a/test_problems/cathermo/HMW_test_3/HMW_test_3.cpp b/test_problems/cathermo/HMW_test_3/HMW_test_3.cpp
index e6d911e73..5c001d211 100644
--- a/test_problems/cathermo/HMW_test_3/HMW_test_3.cpp
+++ b/test_problems/cathermo/HMW_test_3/HMW_test_3.cpp
@@ -15,9 +15,9 @@
 #include "HMWSoln.h"
 #endif
 
+using namespace std;
 using namespace Cantera;
 
-
 void printUsage() {
     cout << "usage: HMW_test_1 " <<  endl;
     cout <<"                -> Everything is hardwired" << endl;