diff --git a/dumux/material/components/iapws/common.hh b/dumux/material/components/iapws/common.hh
index 78b42ddcd8e0e545ec4f6b8f1b09f2c09f242390..0af598635eec6bb2927bc9891bb79b6158db40df 100644
--- a/dumux/material/components/iapws/common.hh
+++ b/dumux/material/components/iapws/common.hh
@@ -201,7 +201,7 @@ public:
         Scalar Tpow = Troot;
         Scalar lam = 0;
 
-        for(int k = 0; k < thcond_a_count; ++k) {
+        for(unsigned int k = 0; k < thcond_a_count; ++k) {
             lam += thcond_a[k] * Tpow;
             Tpow *= Tbar;
         }
diff --git a/dumux/material/fluidsystems/h2on2.hh b/dumux/material/fluidsystems/h2on2.hh
index 2a939a938af494482225faa0e932a1c7301ff24a..f7f0fa9652d3794d5c7eb494a950ad5e601c0b18 100644
--- a/dumux/material/fluidsystems/h2on2.hh
+++ b/dumux/material/fluidsystems/h2on2.hh
@@ -98,8 +98,9 @@ public:
      */
     static const std::string& phaseName(int phaseIdx)
     {
+        static const std::string name[] = { std::string("w"), std::string("n") };
         assert(0 <= phaseIdx && phaseIdx < numPhases);
-        return phaseIdx == wPhaseIdx ? "w" : "n";
+        return name[phaseIdx];
     }
 
     /*!