diff --git a/opm/material/Constants.hpp b/opm/material/Constants.hpp
index 9c0ff12ca..9305f385b 100644
--- a/opm/material/Constants.hpp
+++ b/opm/material/Constants.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::Constants
  */
-#ifndef OPM_CONSTANTS_HH
-#define OPM_CONSTANTS_HH
+#ifndef OPM_CONSTANTS_HPP
+#define OPM_CONSTANTS_HPP
 
 #include <cmath>
 
diff --git a/opm/material/DynamicTabulated2dFunction.hpp b/opm/material/DynamicTabulated2dFunction.hpp
index 0c2d56b5d..4d652eade 100644
--- a/opm/material/DynamicTabulated2dFunction.hpp
+++ b/opm/material/DynamicTabulated2dFunction.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::DynamicTabulated2DFunction
  */
-#ifndef OPM_DYNAMIC_TABULATED_2D_FUNCTION_HH
-#define OPM_DYNAMIC_TABULATED_2D_FUNCTION_HH
+#ifndef OPM_DYNAMIC_TABULATED_2D_FUNCTION_HPP
+#define OPM_DYNAMIC_TABULATED_2D_FUNCTION_HPP
 
 #include <opm/core/utility/Exceptions.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
diff --git a/opm/material/IdealGas.hpp b/opm/material/IdealGas.hpp
index 1e85dc342..7e3df8d5b 100644
--- a/opm/material/IdealGas.hpp
+++ b/opm/material/IdealGas.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::IdealGas
  */
-#ifndef OPM_IDEAL_GAS_HH
-#define OPM_IDEAL_GAS_HH
+#ifndef OPM_IDEAL_GAS_HPP
+#define OPM_IDEAL_GAS_HPP
 
 #include <opm/material/Constants.hpp>
 
diff --git a/opm/material/StaticTabulated2dFunction.hpp b/opm/material/StaticTabulated2dFunction.hpp
index 3b337668b..5503d5c21 100644
--- a/opm/material/StaticTabulated2dFunction.hpp
+++ b/opm/material/StaticTabulated2dFunction.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::StaticTabulated2DFunction
  */
-#ifndef OPM_STATIC_TABULATED_2D_FUNCTION_HH
-#define OPM_STATIC_TABULATED_2D_FUNCTION_HH
+#ifndef OPM_STATIC_TABULATED_2D_FUNCTION_HPP
+#define OPM_STATIC_TABULATED_2D_FUNCTION_HPP
 
 #include <opm/core/utility/Exceptions.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
diff --git a/opm/material/Tabulated2dFunction.hpp b/opm/material/Tabulated2dFunction.hpp
index 939122510..a8ead5e35 100644
--- a/opm/material/Tabulated2dFunction.hpp
+++ b/opm/material/Tabulated2dFunction.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::Tabulated2DFunction
  */
-#ifndef OPM_TABULATED_2D_FUNCTION_HH
-#define OPM_TABULATED_2D_FUNCTION_HH
+#ifndef OPM_TABULATED_2D_FUNCTION_HPP
+#define OPM_TABULATED_2D_FUNCTION_HPP
 
 #include <opm/core/utility/Exceptions.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
diff --git a/opm/material/Valgrind.hpp b/opm/material/Valgrind.hpp
index b177aaec5..ac3845968 100644
--- a/opm/material/Valgrind.hpp
+++ b/opm/material/Valgrind.hpp
@@ -20,8 +20,8 @@
  * \file
  * \brief Some templates to wrap the valgrind macros
  */
-#ifndef OPM_VALGRIND_HH
-#define OPM_VALGRIND_HH
+#ifndef OPM_VALGRIND_HPP
+#define OPM_VALGRIND_HPP
 
 #include <opm/core/utility/Unused.hpp>
 
diff --git a/opm/material/binarycoefficients/Air_Mesitylene.hpp b/opm/material/binarycoefficients/Air_Mesitylene.hpp
index 28b6029b8..3bfdf7c7f 100644
--- a/opm/material/binarycoefficients/Air_Mesitylene.hpp
+++ b/opm/material/binarycoefficients/Air_Mesitylene.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::Air_Mesitylene
  */
-#ifndef OPM_BINARY_COEFF_AIR_MESITYLENE_HH
-#define OPM_BINARY_COEFF_AIR_MESITYLENE_HH
+#ifndef OPM_BINARY_COEFF_AIR_MESITYLENE_HPP
+#define OPM_BINARY_COEFF_AIR_MESITYLENE_HPP
 
 #include <opm/material/components/Air.hpp>
 #include <opm/material/components/Mesitylene.hpp>
diff --git a/opm/material/binarycoefficients/Air_Xylene.hpp b/opm/material/binarycoefficients/Air_Xylene.hpp
index 440147dbf..1d35958cb 100644
--- a/opm/material/binarycoefficients/Air_Xylene.hpp
+++ b/opm/material/binarycoefficients/Air_Xylene.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::Air_Xylene
  */
-#ifndef OPM_BINARY_COEFF_AIR_XYLENE_HH
-#define OPM_BINARY_COEFF_AIR_XYLENE_HH
+#ifndef OPM_BINARY_COEFF_AIR_XYLENE_HPP
+#define OPM_BINARY_COEFF_AIR_XYLENE_HPP
 
 #include <opm/material/components/Air.hpp>
 #include <opm/material/components/Xylene.hpp>
diff --git a/opm/material/binarycoefficients/Brine_CO2.hpp b/opm/material/binarycoefficients/Brine_CO2.hpp
index c021e40a7..c521bd7f7 100644
--- a/opm/material/binarycoefficients/Brine_CO2.hpp
+++ b/opm/material/binarycoefficients/Brine_CO2.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::BinaryCoeff::Brine_CO2
  */
-#ifndef OPM_BINARY_COEFF_BRINE_CO2_HH
-#define OPM_BINARY_COEFF_BRINE_CO2_HH
+#ifndef OPM_BINARY_COEFF_BRINE_CO2_HPP
+#define OPM_BINARY_COEFF_BRINE_CO2_HPP
 
 #include <opm/material/components/Brine.hpp>
 #include <opm/material/components/H2O.hpp>
diff --git a/opm/material/binarycoefficients/FullerMethod.hpp b/opm/material/binarycoefficients/FullerMethod.hpp
index 30ab1abfd..18472100d 100644
--- a/opm/material/binarycoefficients/FullerMethod.hpp
+++ b/opm/material/binarycoefficients/FullerMethod.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::fullerMethod
  */
-#ifndef OPM_FULLERMETHOD_HH
-#define OPM_FULLERMETHOD_HH
+#ifndef OPM_FULLERMETHOD_HPP
+#define OPM_FULLERMETHOD_HPP
 
 #include <opm/core/utility/Average.hpp>
 
diff --git a/opm/material/binarycoefficients/H2O_Air.hpp b/opm/material/binarycoefficients/H2O_Air.hpp
index 814e9fad6..e1173246b 100644
--- a/opm/material/binarycoefficients/H2O_Air.hpp
+++ b/opm/material/binarycoefficients/H2O_Air.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::H2O_Air
  */
-#ifndef OPM_BINARY_COEFF_H2O_AIR_HH
-#define OPM_BINARY_COEFF_H2O_AIR_HH
+#ifndef OPM_BINARY_COEFF_H2O_AIR_HPP
+#define OPM_BINARY_COEFF_H2O_AIR_HPP
 
 #include <cmath>
 
diff --git a/opm/material/binarycoefficients/H2O_CO2.hpp b/opm/material/binarycoefficients/H2O_CO2.hpp
index 212703b9b..61b76f47b 100644
--- a/opm/material/binarycoefficients/H2O_CO2.hpp
+++ b/opm/material/binarycoefficients/H2O_CO2.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::BinaryCoeff::H2O_CO2
  */
-#ifndef OPM_BINARY_COEFF_H2O_CO2_HH
-#define OPM_BINARY_COEFF_H2O_CO2_HH
+#ifndef OPM_BINARY_COEFF_H2O_CO2_HPP
+#define OPM_BINARY_COEFF_H2O_CO2_HPP
 
 #include <opm/material/binarycoefficients/HenryIapws.hpp>
 #include <opm/material/binarycoefficients/FullerMethod.hpp>
diff --git a/opm/material/binarycoefficients/H2O_Mesitylene.hpp b/opm/material/binarycoefficients/H2O_Mesitylene.hpp
index 7044cda3b..eefadffd0 100644
--- a/opm/material/binarycoefficients/H2O_Mesitylene.hpp
+++ b/opm/material/binarycoefficients/H2O_Mesitylene.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::H2O_Mesitylene
  */
-#ifndef OPM_BINARY_COEFF_H2O_MESITYLENE_HH
-#define OPM_BINARY_COEFF_H2O_MESITYLENE_HH
+#ifndef OPM_BINARY_COEFF_H2O_MESITYLENE_HPP
+#define OPM_BINARY_COEFF_H2O_MESITYLENE_HPP
 
 #include <opm/material/components/H2O.hpp>
 #include <opm/material/components/Mesitylene.hpp>
diff --git a/opm/material/binarycoefficients/H2O_N2.hpp b/opm/material/binarycoefficients/H2O_N2.hpp
index 028dcb01f..c5dfd216f 100644
--- a/opm/material/binarycoefficients/H2O_N2.hpp
+++ b/opm/material/binarycoefficients/H2O_N2.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::H2O_N2
  */
-#ifndef OPM_BINARY_COEFF_H2O_N2_HH
-#define OPM_BINARY_COEFF_H2O_N2_HH
+#ifndef OPM_BINARY_COEFF_H2O_N2_HPP
+#define OPM_BINARY_COEFF_H2O_N2_HPP
 
 #include "HenryIapws.hpp"
 #include "FullerMethod.hpp"
diff --git a/opm/material/binarycoefficients/H2O_Xylene.hpp b/opm/material/binarycoefficients/H2O_Xylene.hpp
index 29451a0d4..a26b22e7d 100644
--- a/opm/material/binarycoefficients/H2O_Xylene.hpp
+++ b/opm/material/binarycoefficients/H2O_Xylene.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BinaryCoeff::H2O_Xylene
  */
-#ifndef OPM_BINARY_COEFF_H2O_XYLENE_HH
-#define OPM_BINARY_COEFF_H2O_XYLENE_HH
+#ifndef OPM_BINARY_COEFF_H2O_XYLENE_HPP
+#define OPM_BINARY_COEFF_H2O_XYLENE_HPP
 
 #include <opm/material/components/H2O.hpp>
 #include <opm/material/components/Xylene.hpp>
diff --git a/opm/material/binarycoefficients/HenryIapws.hpp b/opm/material/binarycoefficients/HenryIapws.hpp
index a7d0b3012..447e49d64 100644
--- a/opm/material/binarycoefficients/HenryIapws.hpp
+++ b/opm/material/binarycoefficients/HenryIapws.hpp
@@ -21,8 +21,8 @@
  *
  * \brief The IAPWS formulation of Henry coefficients in water.
  */
-#ifndef OPM_HENRY_IAPWS_HH
-#define OPM_HENRY_IAPWS_HH
+#ifndef OPM_HENRY_IAPWS_HPP
+#define OPM_HENRY_IAPWS_HPP
 
 #include <opm/material/components/H2O.hpp>
 
@@ -81,4 +81,4 @@ inline Scalar henryIAPWS(Scalar E,
 }
 } // namespace Opm
 
-#endif // OPM_HENRY_IAPWS_HH
+#endif // OPM_HENRY_IAPWS_HPP
diff --git a/opm/material/components/Air.hpp b/opm/material/components/Air.hpp
index c6bee027b..e8adf8799 100644
--- a/opm/material/components/Air.hpp
+++ b/opm/material/components/Air.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::Air
  */
-#ifndef OPM_AIR_HH
-#define OPM_AIR_HH
+#ifndef OPM_AIR_HPP
+#define OPM_AIR_HPP
 
 #include <opm/material/components/Component.hpp>
 #include <opm/material/IdealGas.hpp>
diff --git a/opm/material/components/Brine.hpp b/opm/material/components/Brine.hpp
index 6fa839d42..09124d43c 100644
--- a/opm/material/components/Brine.hpp
+++ b/opm/material/components/Brine.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::Brine
  */
-#ifndef OPM_BRINE_HH
-#define OPM_BRINE_HH
+#ifndef OPM_BRINE_HPP
+#define OPM_BRINE_HPP
 
 #include <opm/material/components/Component.hpp>
 
diff --git a/opm/material/components/CO2.hpp b/opm/material/components/CO2.hpp
index a58348d51..1f21e9902 100644
--- a/opm/material/components/CO2.hpp
+++ b/opm/material/components/CO2.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::CO2
  */
-#ifndef OPM_CO2_HH
-#define OPM_CO2_HH
+#ifndef OPM_CO2_HPP
+#define OPM_CO2_HPP
 
 #include <opm/core/utility/Exceptions.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
diff --git a/opm/material/components/Component.hpp b/opm/material/components/Component.hpp
index 142203779..9d12ba446 100644
--- a/opm/material/components/Component.hpp
+++ b/opm/material/components/Component.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::Component
  */
-#ifndef OPM_COMPONENT_HH
-#define OPM_COMPONENT_HH
+#ifndef OPM_COMPONENT_HPP
+#define OPM_COMPONENT_HPP
 
 #include <opm/core/utility/ErrorMacros.hpp>
 #include <opm/core/utility/Exceptions.hpp>
diff --git a/opm/material/components/Dnapl.hpp b/opm/material/components/Dnapl.hpp
index 581726ead..da06bce8d 100644
--- a/opm/material/components/Dnapl.hpp
+++ b/opm/material/components/Dnapl.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::DNAPL
  */
-#ifndef OPM_DNAPL_HH
-#define OPM_DNAPL_HH
+#ifndef OPM_DNAPL_HPP
+#define OPM_DNAPL_HPP
 
 #include <opm/material/IdealGas.hpp>
 #include "Component.hpp"
diff --git a/opm/material/components/H2O.hpp b/opm/material/components/H2O.hpp
index f5e9cf66e..27700d86d 100644
--- a/opm/material/components/H2O.hpp
+++ b/opm/material/components/H2O.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::H2O
  */
-#ifndef OPM_H2O_HH
-#define OPM_H2O_HH
+#ifndef OPM_H2O_HPP
+#define OPM_H2O_HPP
 
 #include <cmath>
 #include <cassert>
diff --git a/opm/material/components/Lnapl.hpp b/opm/material/components/Lnapl.hpp
index 8db98981b..7cb93ef29 100644
--- a/opm/material/components/Lnapl.hpp
+++ b/opm/material/components/Lnapl.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::LNAPL
  */
-#ifndef OPM_LNAPL_HH
-#define OPM_LNAPL_HH
+#ifndef OPM_LNAPL_HPP
+#define OPM_LNAPL_HPP
 
 #include "Component.hpp"
 
diff --git a/opm/material/components/Mesitylene.hpp b/opm/material/components/Mesitylene.hpp
index b5907e6c2..e3af37bcd 100644
--- a/opm/material/components/Mesitylene.hpp
+++ b/opm/material/components/Mesitylene.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::Mesitylene
  */
-#ifndef OPM_MESITYLENE_HH
-#define OPM_MESITYLENE_HH
+#ifndef OPM_MESITYLENE_HPP
+#define OPM_MESITYLENE_HPP
 
 #include <opm/material/IdealGas.hpp>
 #include <opm/material/components/Component.hpp>
diff --git a/opm/material/components/N2.hpp b/opm/material/components/N2.hpp
index 499e09072..13f16046a 100644
--- a/opm/material/components/N2.hpp
+++ b/opm/material/components/N2.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::N2
  */
-#ifndef OPM_N2_HH
-#define OPM_N2_HH
+#ifndef OPM_N2_HPP
+#define OPM_N2_HPP
 
 #include <opm/material/IdealGas.hpp>
 
diff --git a/opm/material/components/NullComponent.hpp b/opm/material/components/NullComponent.hpp
index fe7caf58a..744a6df5a 100644
--- a/opm/material/components/NullComponent.hpp
+++ b/opm/material/components/NullComponent.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::NullComponent
  */
-#ifndef OPM_NULL_COMPONENT_HH
-#define OPM_NULL_COMPONENT_HH
+#ifndef OPM_NULL_COMPONENT_HPP
+#define OPM_NULL_COMPONENT_HPP
 
 #include "Component.hpp"
 
diff --git a/opm/material/components/SimpleCO2.hpp b/opm/material/components/SimpleCO2.hpp
index 578c26e12..4c9b79608 100644
--- a/opm/material/components/SimpleCO2.hpp
+++ b/opm/material/components/SimpleCO2.hpp
@@ -23,8 +23,8 @@
  *
  * \copydoc Opm::SimpleCO2
  */
-#ifndef OPM_SIMPLE_CO2_HH
-#define OPM_SIMPLE_CO2_HH
+#ifndef OPM_SIMPLE_CO2_HPP
+#define OPM_SIMPLE_CO2_HPP
 
 #include <opm/material/IdealGas.hpp>
 #include <opm/material/components/Component.hpp>
diff --git a/opm/material/components/SimpleH2O.hpp b/opm/material/components/SimpleH2O.hpp
index ef861a885..cb6461004 100644
--- a/opm/material/components/SimpleH2O.hpp
+++ b/opm/material/components/SimpleH2O.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::SimpleH2O
  */
-#ifndef OPM_SIMPLE_H2O_HH
-#define OPM_SIMPLE_H2O_HH
+#ifndef OPM_SIMPLE_H2O_HPP
+#define OPM_SIMPLE_H2O_HPP
 
 #include <opm/material/IdealGas.hpp>
 
diff --git a/opm/material/components/TabulatedComponent.hpp b/opm/material/components/TabulatedComponent.hpp
index 10145e3fa..4646a128b 100644
--- a/opm/material/components/TabulatedComponent.hpp
+++ b/opm/material/components/TabulatedComponent.hpp
@@ -23,8 +23,8 @@
  *
  * \copydoc Opm::TabulatedComponent
  */
-#ifndef OPM_TABULATED_COMPONENT_HH
-#define OPM_TABULATED_COMPONENT_HH
+#ifndef OPM_TABULATED_COMPONENT_HPP
+#define OPM_TABULATED_COMPONENT_HPP
 
 #include <cmath>
 #include <limits>
diff --git a/opm/material/components/Unit.hpp b/opm/material/components/Unit.hpp
index daf41bd98..e71289506 100644
--- a/opm/material/components/Unit.hpp
+++ b/opm/material/components/Unit.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::Unit
  */
-#ifndef OPM_UNIT_HH
-#define OPM_UNIT_HH
+#ifndef OPM_UNIT_HPP
+#define OPM_UNIT_HPP
 
 #include "Component.hpp"
 
diff --git a/opm/material/components/Xylene.hpp b/opm/material/components/Xylene.hpp
index da257cfc5..9b0158039 100644
--- a/opm/material/components/Xylene.hpp
+++ b/opm/material/components/Xylene.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::Xylene
  */
-#ifndef OPM_XYLENE_HH
-#define OPM_XYLENE_HH
+#ifndef OPM_XYLENE_HPP
+#define OPM_XYLENE_HPP
 
 #include <cmath>
 #include <opm/material/IdealGas.hpp>
diff --git a/opm/material/components/iapws/Common.hpp b/opm/material/components/iapws/Common.hpp
index 586003c32..76675e9b5 100644
--- a/opm/material/components/iapws/Common.hpp
+++ b/opm/material/components/iapws/Common.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::IAPWS::Common
  */
-#ifndef OPM_IAPWS_COMMON_HH
-#define OPM_IAPWS_COMMON_HH
+#ifndef OPM_IAPWS_COMMON_HPP
+#define OPM_IAPWS_COMMON_HPP
 
 #include <opm/material/Constants.hpp>
 
diff --git a/opm/material/components/iapws/Region1.hpp b/opm/material/components/iapws/Region1.hpp
index 7258fafff..e55b25d54 100644
--- a/opm/material/components/iapws/Region1.hpp
+++ b/opm/material/components/iapws/Region1.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::IAPWS::Region1
  */
-#ifndef OPM_IAPWS_REGION1_HH
-#define OPM_IAPWS_REGION1_HH
+#ifndef OPM_IAPWS_REGION1_HPP
+#define OPM_IAPWS_REGION1_HPP
 
 #include <cmath>
 
diff --git a/opm/material/components/iapws/Region2.hpp b/opm/material/components/iapws/Region2.hpp
index b5cc1c267..5cbc199d4 100644
--- a/opm/material/components/iapws/Region2.hpp
+++ b/opm/material/components/iapws/Region2.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::IAPWS::Region2
  */
-#ifndef OPM_IAPWS_REGION2_HH
-#define OPM_IAPWS_REGION2_HH
+#ifndef OPM_IAPWS_REGION2_HPP
+#define OPM_IAPWS_REGION2_HPP
 
 #include <cmath>
 
diff --git a/opm/material/components/iapws/Region4.hpp b/opm/material/components/iapws/Region4.hpp
index 7a3ae3fb0..c277d06d9 100644
--- a/opm/material/components/iapws/Region4.hpp
+++ b/opm/material/components/iapws/Region4.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::IAPWS::Region4
  */
-#ifndef OPM_IAPWS_REGION4_HH
-#define OPM_IAPWS_REGION4_HH
+#ifndef OPM_IAPWS_REGION4_HPP
+#define OPM_IAPWS_REGION4_HPP
 
 #include <cmath>
 
diff --git a/opm/material/constraintsolvers/CompositionFromFugacities.hpp b/opm/material/constraintsolvers/CompositionFromFugacities.hpp
index fc11cc55a..fc12083f3 100644
--- a/opm/material/constraintsolvers/CompositionFromFugacities.hpp
+++ b/opm/material/constraintsolvers/CompositionFromFugacities.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::CompositionFromFugacities
  */
-#ifndef OPM_COMPOSITION_FROM_FUGACITIES_HH
-#define OPM_COMPOSITION_FROM_FUGACITIES_HH
+#ifndef OPM_COMPOSITION_FROM_FUGACITIES_HPP
+#define OPM_COMPOSITION_FROM_FUGACITIES_HPP
 
 #include <dune/common/fvector.hh>
 #include <dune/common/fmatrix.hh>
diff --git a/opm/material/constraintsolvers/ComputeFromReferencePhase.hpp b/opm/material/constraintsolvers/ComputeFromReferencePhase.hpp
index 0c22a66d8..d5d21797a 100644
--- a/opm/material/constraintsolvers/ComputeFromReferencePhase.hpp
+++ b/opm/material/constraintsolvers/ComputeFromReferencePhase.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::ComputeFromReferencePhase
  */
-#ifndef OPM_COMPUTE_FROM_REFERENCE_PHASE_HH
-#define OPM_COMPUTE_FROM_REFERENCE_PHASE_HH
+#ifndef OPM_COMPUTE_FROM_REFERENCE_PHASE_HPP
+#define OPM_COMPUTE_FROM_REFERENCE_PHASE_HPP
 
 #include <opm/material/constraintsolvers/CompositionFromFugacities.hpp>
 
diff --git a/opm/material/constraintsolvers/ImmiscibleFlash.hpp b/opm/material/constraintsolvers/ImmiscibleFlash.hpp
index 3b6d0cb6f..aab3a491b 100644
--- a/opm/material/constraintsolvers/ImmiscibleFlash.hpp
+++ b/opm/material/constraintsolvers/ImmiscibleFlash.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::ImmiscibleFlash
  */
-#ifndef OPM_IMMISCIBLE_FLASH_HH
-#define OPM_IMMISCIBLE_FLASH_HH
+#ifndef OPM_IMMISCIBLE_FLASH_HPP
+#define OPM_IMMISCIBLE_FLASH_HPP
 
 #include <opm/core/utility/ErrorMacros.hpp>
 #include <opm/core/utility/Exceptions.hpp>
diff --git a/opm/material/constraintsolvers/MiscibleMultiPhaseComposition.hpp b/opm/material/constraintsolvers/MiscibleMultiPhaseComposition.hpp
index 72b19fd9c..492ef01c9 100644
--- a/opm/material/constraintsolvers/MiscibleMultiPhaseComposition.hpp
+++ b/opm/material/constraintsolvers/MiscibleMultiPhaseComposition.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::MiscibleMultiPhaseComposition
  */
-#ifndef OPM_MISCIBLE_MULTIPHASE_COMPOSITION_HH
-#define OPM_MISCIBLE_MULTIPHASE_COMPOSITION_HH
+#ifndef OPM_MISCIBLE_MULTIPHASE_COMPOSITION_HPP
+#define OPM_MISCIBLE_MULTIPHASE_COMPOSITION_HPP
 
 #include <dune/common/fvector.hh>
 #include <dune/common/fmatrix.hh>
diff --git a/opm/material/constraintsolvers/NcpFlash.hpp b/opm/material/constraintsolvers/NcpFlash.hpp
index de27791dc..68d5c0fdc 100644
--- a/opm/material/constraintsolvers/NcpFlash.hpp
+++ b/opm/material/constraintsolvers/NcpFlash.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::NcpFlash
  */
-#ifndef OPM_NCP_FLASH_HH
-#define OPM_NCP_FLASH_HH
+#ifndef OPM_NCP_FLASH_HPP
+#define OPM_NCP_FLASH_HPP
 
 #include <dune/common/fvector.hh>
 #include <dune/common/fmatrix.hh>
diff --git a/opm/material/eos/PengRobinson.hpp b/opm/material/eos/PengRobinson.hpp
index c9aa7e712..be0529802 100644
--- a/opm/material/eos/PengRobinson.hpp
+++ b/opm/material/eos/PengRobinson.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::PengRobinson
  */
-#ifndef OPM_PENG_ROBINSON_HH
-#define OPM_PENG_ROBINSON_HH
+#ifndef OPM_PENG_ROBINSON_HPP
+#define OPM_PENG_ROBINSON_HPP
 
 #include <opm/material/fluidstates/TemperatureOverlayFluidState.hpp>
 #include <opm/material/IdealGas.hpp>
diff --git a/opm/material/eos/PengRobinsonMixture.hpp b/opm/material/eos/PengRobinsonMixture.hpp
index 989b2de72..794a3ee9c 100644
--- a/opm/material/eos/PengRobinsonMixture.hpp
+++ b/opm/material/eos/PengRobinsonMixture.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::PengRobinsonMixture
  */
-#ifndef OPM_PENG_ROBINSON_MIXTURE_HH
-#define OPM_PENG_ROBINSON_MIXTURE_HH
+#ifndef OPM_PENG_ROBINSON_MIXTURE_HPP
+#define OPM_PENG_ROBINSON_MIXTURE_HPP
 
 #include "PengRobinson.hpp"
 
diff --git a/opm/material/eos/PengRobinsonParams.hpp b/opm/material/eos/PengRobinsonParams.hpp
index 77867e332..a05c6e3b0 100644
--- a/opm/material/eos/PengRobinsonParams.hpp
+++ b/opm/material/eos/PengRobinsonParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::PengRobinsonParams
  */
-#ifndef OPM_PENG_ROBINSON_PARAMS_HH
-#define OPM_PENG_ROBINSON_PARAMS_HH
+#ifndef OPM_PENG_ROBINSON_PARAMS_HPP
+#define OPM_PENG_ROBINSON_PARAMS_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/eos/PengRobinsonparamsMixture.hpp b/opm/material/eos/PengRobinsonparamsMixture.hpp
index e663f2984..0e1db0952 100644
--- a/opm/material/eos/PengRobinsonparamsMixture.hpp
+++ b/opm/material/eos/PengRobinsonparamsMixture.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::PengRobinsonParamsMixture
  */
-#ifndef OPM_PENG_ROBINSON_PARAMS_MIXTURE_HH
-#define OPM_PENG_ROBINSON_PARAMS_MIXTURE_HH
+#ifndef OPM_PENG_ROBINSON_PARAMS_MIXTURE_HPP
+#define OPM_PENG_ROBINSON_PARAMS_MIXTURE_HPP
 
 #include <algorithm>
 #include <opm/material/Constants.hpp>
diff --git a/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchten.hpp b/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchten.hpp
index 51717fe5d..4350968d2 100644
--- a/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchten.hpp
+++ b/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchten.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::ThreePParkerVanGenuchten
  */
-#ifndef OPM_3P_PARKER_VAN_GENUCHTEN_HH
-#define OPM_3P_PARKER_VAN_GENUCHTEN_HH
+#ifndef OPM_3P_PARKER_VAN_GENUCHTEN_HPP
+#define OPM_3P_PARKER_VAN_GENUCHTEN_HPP
 
 #include "3pParkerVanGenuchtenParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchtenParams.hpp b/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchtenParams.hpp
index 17c57bbf8..5c5b4225a 100644
--- a/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchtenParams.hpp
+++ b/opm/material/fluidmatrixinteractions/3p/3pParkerVanGenuchtenParams.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::ParkerVanGen3PParams
  */
-#ifndef OPM_3P_PARKER_VAN_GENUCHTEN_PARAMS_HH
-#define OPM_3P_PARKER_VAN_GENUCHTEN_PARAMS_HH
+#ifndef OPM_3P_PARKER_VAN_GENUCHTEN_PARAMS_HPP
+#define OPM_3P_PARKER_VAN_GENUCHTEN_PARAMS_HPP
 
 #include <dune/common/fvector.hh>
 
diff --git a/opm/material/fluidmatrixinteractions/BrooksCorey.hpp b/opm/material/fluidmatrixinteractions/BrooksCorey.hpp
index 15634f279..e612fff25 100644
--- a/opm/material/fluidmatrixinteractions/BrooksCorey.hpp
+++ b/opm/material/fluidmatrixinteractions/BrooksCorey.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BrooksCorey
  */
-#ifndef OPM_BROOKS_COREY_HH
-#define OPM_BROOKS_COREY_HH
+#ifndef OPM_BROOKS_COREY_HPP
+#define OPM_BROOKS_COREY_HPP
 
 #include "BrooksCoreyParams.hpp"
 
@@ -445,4 +445,4 @@ public:
 };
 } // namespace Opm
 
-#endif // BROOKS_COREY_HH
+#endif // BROOKS_COREY_HPP
diff --git a/opm/material/fluidmatrixinteractions/BrooksCoreyParams.hpp b/opm/material/fluidmatrixinteractions/BrooksCoreyParams.hpp
index 9ccc23e25..c01c19876 100644
--- a/opm/material/fluidmatrixinteractions/BrooksCoreyParams.hpp
+++ b/opm/material/fluidmatrixinteractions/BrooksCoreyParams.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::BrooksCoreyParams
  */
-#ifndef OPM_BROOKS_COREY_PARAMS_HH
-#define OPM_BROOKS_COREY_PARAMS_HH
+#ifndef OPM_BROOKS_COREY_PARAMS_HPP
+#define OPM_BROOKS_COREY_PARAMS_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidmatrixinteractions/EclDefaultMaterial.hpp b/opm/material/fluidmatrixinteractions/EclDefaultMaterial.hpp
index 4d1099661..9d80027ce 100644
--- a/opm/material/fluidmatrixinteractions/EclDefaultMaterial.hpp
+++ b/opm/material/fluidmatrixinteractions/EclDefaultMaterial.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::EclDefaultMaterial
  */
-#ifndef OPM_ECL_DEFAULT_MATERIAL_HH
-#define OPM_ECL_DEFAULT_MATERIAL_HH
+#ifndef OPM_ECL_DEFAULT_MATERIAL_HPP
+#define OPM_ECL_DEFAULT_MATERIAL_HPP
 
 #include "EclDefaultMaterialParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/EclDefaultMaterialParams.hpp b/opm/material/fluidmatrixinteractions/EclDefaultMaterialParams.hpp
index b204aa065..eb5270ce5 100644
--- a/opm/material/fluidmatrixinteractions/EclDefaultMaterialParams.hpp
+++ b/opm/material/fluidmatrixinteractions/EclDefaultMaterialParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::EclDefaultMaterialParams
  */
-#ifndef OPM_ECL_DEFAULT_MATERIAL_PARAMS_HH
-#define OPM_ECL_DEFAULT_MATERIAL_PARAMS_HH
+#ifndef OPM_ECL_DEFAULT_MATERIAL_PARAMS_HPP
+#define OPM_ECL_DEFAULT_MATERIAL_PARAMS_HPP
 
 #include <type_traits>
 
diff --git a/opm/material/fluidmatrixinteractions/EffToAbsLaw.hpp b/opm/material/fluidmatrixinteractions/EffToAbsLaw.hpp
index f3b74b993..fe612f23a 100644
--- a/opm/material/fluidmatrixinteractions/EffToAbsLaw.hpp
+++ b/opm/material/fluidmatrixinteractions/EffToAbsLaw.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::EffToAbsLaw
  */
-#ifndef OPM_EFF_TO_ABS_LAW_HH
-#define OPM_EFF_TO_ABS_LAW_HH
+#ifndef OPM_EFF_TO_ABS_LAW_HPP
+#define OPM_EFF_TO_ABS_LAW_HPP
 
 #include "EffToAbsLawParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/EffToAbsLawParams.hpp b/opm/material/fluidmatrixinteractions/EffToAbsLawParams.hpp
index 1a5b8fd01..7737ccfcc 100644
--- a/opm/material/fluidmatrixinteractions/EffToAbsLawParams.hpp
+++ b/opm/material/fluidmatrixinteractions/EffToAbsLawParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::EffToAbsLawParams
  */
-#ifndef OPM_EFF_TO_ABS_LAW_PARAMS_HH
-#define OPM_EFF_TO_ABS_LAW_PARAMS_HH
+#ifndef OPM_EFF_TO_ABS_LAW_PARAMS_HPP
+#define OPM_EFF_TO_ABS_LAW_PARAMS_HPP
 
 namespace Opm {
 /*!
diff --git a/opm/material/fluidmatrixinteractions/LinearMaterial.hpp b/opm/material/fluidmatrixinteractions/LinearMaterial.hpp
index 885059866..11f14c530 100644
--- a/opm/material/fluidmatrixinteractions/LinearMaterial.hpp
+++ b/opm/material/fluidmatrixinteractions/LinearMaterial.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::LinearMaterial
  */
-#ifndef OPM_LINEAR_MATERIAL_HH
-#define OPM_LINEAR_MATERIAL_HH
+#ifndef OPM_LINEAR_MATERIAL_HPP
+#define OPM_LINEAR_MATERIAL_HPP
 
 #include "LinearMaterialParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/LinearMaterialParams.hpp b/opm/material/fluidmatrixinteractions/LinearMaterialParams.hpp
index b411d0c96..0d502eee6 100644
--- a/opm/material/fluidmatrixinteractions/LinearMaterialParams.hpp
+++ b/opm/material/fluidmatrixinteractions/LinearMaterialParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::LinearMaterialParams
  */
-#ifndef OPM_LINEAR_MATERIAL_PARAMS_HH
-#define OPM_LINEAR_MATERIAL_PARAMS_HH
+#ifndef OPM_LINEAR_MATERIAL_PARAMS_HPP
+#define OPM_LINEAR_MATERIAL_PARAMS_HPP
 
 namespace Opm {
 
diff --git a/opm/material/fluidmatrixinteractions/MaterialTraits.hpp b/opm/material/fluidmatrixinteractions/MaterialTraits.hpp
index 0c7bb3378..d9fcd842b 100644
--- a/opm/material/fluidmatrixinteractions/MaterialTraits.hpp
+++ b/opm/material/fluidmatrixinteractions/MaterialTraits.hpp
@@ -24,8 +24,8 @@
  * and the fluid-matrix interaction laws. This includes stuff like the
  * index of the wetting and non-wetting phase, etc.
  */
-#ifndef OPM_MATERIAL_TRAITS_HH
-#define OPM_MATERIAL_TRAITS_HH
+#ifndef OPM_MATERIAL_TRAITS_HPP
+#define OPM_MATERIAL_TRAITS_HPP
 
 namespace Opm {
 /*!
diff --git a/opm/material/fluidmatrixinteractions/NullMaterial.hpp b/opm/material/fluidmatrixinteractions/NullMaterial.hpp
index 0fee9d66c..c4b553899 100644
--- a/opm/material/fluidmatrixinteractions/NullMaterial.hpp
+++ b/opm/material/fluidmatrixinteractions/NullMaterial.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::NullMaterial
  */
-#ifndef OPM_NULL_MATERIAL_HH
-#define OPM_NULL_MATERIAL_HH
+#ifndef OPM_NULL_MATERIAL_HPP
+#define OPM_NULL_MATERIAL_HPP
 
 #include "NullMaterialParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/NullMaterialParams.hpp b/opm/material/fluidmatrixinteractions/NullMaterialParams.hpp
index 68d1bdf25..aa99b3a75 100644
--- a/opm/material/fluidmatrixinteractions/NullMaterialParams.hpp
+++ b/opm/material/fluidmatrixinteractions/NullMaterialParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::NullMaterialParams
  */
-#ifndef OPM_NULL_MATERIAL_PARAMS_HH
-#define OPM_NULL_MATERIAL_PARAMS_HH
+#ifndef OPM_NULL_MATERIAL_PARAMS_HPP
+#define OPM_NULL_MATERIAL_PARAMS_HPP
 
 namespace Opm {
 /*!
diff --git a/opm/material/fluidmatrixinteractions/ParkerLenhard.hpp b/opm/material/fluidmatrixinteractions/ParkerLenhard.hpp
index 877a00bbe..0f9c3f089 100644
--- a/opm/material/fluidmatrixinteractions/ParkerLenhard.hpp
+++ b/opm/material/fluidmatrixinteractions/ParkerLenhard.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::ParkerLenhard
  */
-#ifndef OPM_PARKER_LENHARD_HH
-#define OPM_PARKER_LENHARD_HH
+#ifndef OPM_PARKER_LENHARD_HPP
+#define OPM_PARKER_LENHARD_HPP
 
 #include "ParkerLenhardParams.hpp"
 
@@ -730,4 +730,4 @@ private:
 
 } // namespace Opm
 
-#endif // PARKER_LENHARD_HH
+#endif // PARKER_LENHARD_HPP
diff --git a/opm/material/fluidmatrixinteractions/ParkerLenhardParams.hpp b/opm/material/fluidmatrixinteractions/ParkerLenhardParams.hpp
index 7d3edff99..0ce2a25da 100644
--- a/opm/material/fluidmatrixinteractions/ParkerLenhardParams.hpp
+++ b/opm/material/fluidmatrixinteractions/ParkerLenhardParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::ParkerLenhardParams
  */
-#ifndef OPM_PARKER_LENHARD_PARAMS_HH
-#define OPM_PARKER_LENHARD_PARAMS_HH
+#ifndef OPM_PARKER_LENHARD_PARAMS_HPP
+#define OPM_PARKER_LENHARD_PARAMS_HPP
 
 #include <opm/material/fluidmatrixinteractions/RegularizedVanGenuchten.hpp>
 
diff --git a/opm/material/fluidmatrixinteractions/RegularizedBrooksCorey.hpp b/opm/material/fluidmatrixinteractions/RegularizedBrooksCorey.hpp
index 377e699fc..61533d3b0 100644
--- a/opm/material/fluidmatrixinteractions/RegularizedBrooksCorey.hpp
+++ b/opm/material/fluidmatrixinteractions/RegularizedBrooksCorey.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::RegularizedBrooksCorey
  */
-#ifndef REGULARIZED_BROOKS_COREY_HH
-#define REGULARIZED_BROOKS_COREY_HH
+#ifndef REGULARIZED_BROOKS_COREY_HPP
+#define REGULARIZED_BROOKS_COREY_HPP
 
 #include "BrooksCorey.hpp"
 #include "RegularizedBrooksCoreyParams.hpp"
diff --git a/opm/material/fluidmatrixinteractions/RegularizedBrooksCoreyParams.hpp b/opm/material/fluidmatrixinteractions/RegularizedBrooksCoreyParams.hpp
index 25fdebe34..1683a93b3 100644
--- a/opm/material/fluidmatrixinteractions/RegularizedBrooksCoreyParams.hpp
+++ b/opm/material/fluidmatrixinteractions/RegularizedBrooksCoreyParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::RegularizedBrooksCoreyParams
  */
-#ifndef OPM_REGULARIZED_BROOKS_COREY_PARAMS_HH
-#define OPM_REGULARIZED_BROOKS_COREY_PARAMS_HH
+#ifndef OPM_REGULARIZED_BROOKS_COREY_PARAMS_HPP
+#define OPM_REGULARIZED_BROOKS_COREY_PARAMS_HPP
 
 #include "BrooksCoreyParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/RegularizedVanGenuchten.hpp b/opm/material/fluidmatrixinteractions/RegularizedVanGenuchten.hpp
index c71fd28fb..862c91a76 100644
--- a/opm/material/fluidmatrixinteractions/RegularizedVanGenuchten.hpp
+++ b/opm/material/fluidmatrixinteractions/RegularizedVanGenuchten.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::RegularizedVanGenuchten
  */
-#ifndef OPM_REGULARIZED_VAN_GENUCHTEN_HH
-#define OPM_REGULARIZED_VAN_GENUCHTEN_HH
+#ifndef OPM_REGULARIZED_VAN_GENUCHTEN_HPP
+#define OPM_REGULARIZED_VAN_GENUCHTEN_HPP
 
 #include "VanGenuchten.hpp"
 #include "RegularizedVanGenuchtenParams.hpp"
diff --git a/opm/material/fluidmatrixinteractions/RegularizedVanGenuchtenParams.hpp b/opm/material/fluidmatrixinteractions/RegularizedVanGenuchtenParams.hpp
index b9ca83468..6def43a11 100644
--- a/opm/material/fluidmatrixinteractions/RegularizedVanGenuchtenParams.hpp
+++ b/opm/material/fluidmatrixinteractions/RegularizedVanGenuchtenParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::RegularizedVanGenuchtenParams
  */
-#ifndef OPM_REGULARIZED_VAN_GENUCHTEN_PARAMS_HH
-#define OPM_REGULARIZED_VAN_GENUCHTEN_PARAMS_HH
+#ifndef OPM_REGULARIZED_VAN_GENUCHTEN_PARAMS_HPP
+#define OPM_REGULARIZED_VAN_GENUCHTEN_PARAMS_HPP
 
 #include "VanGenuchtenParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/VanGenuchten.hpp b/opm/material/fluidmatrixinteractions/VanGenuchten.hpp
index c9523d2e8..b8ea35cf0 100644
--- a/opm/material/fluidmatrixinteractions/VanGenuchten.hpp
+++ b/opm/material/fluidmatrixinteractions/VanGenuchten.hpp
@@ -22,8 +22,8 @@
  * \file
  * \copydoc Opm::VanGenuchten
  */
-#ifndef OPM_VAN_GENUCHTEN_HH
-#define OPM_VAN_GENUCHTEN_HH
+#ifndef OPM_VAN_GENUCHTEN_HPP
+#define OPM_VAN_GENUCHTEN_HPP
 
 #include "VanGenuchtenParams.hpp"
 
diff --git a/opm/material/fluidmatrixinteractions/VanGenuchtenParams.hpp b/opm/material/fluidmatrixinteractions/VanGenuchtenParams.hpp
index 9e19ff084..28c233415 100644
--- a/opm/material/fluidmatrixinteractions/VanGenuchtenParams.hpp
+++ b/opm/material/fluidmatrixinteractions/VanGenuchtenParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::VanGenuchtenParams
  */
-#ifndef VAN_GENUCHTEN_PARAMS_HH
-#define VAN_GENUCHTEN_PARAMS_HH
+#ifndef VAN_GENUCHTEN_PARAMS_HPP
+#define VAN_GENUCHTEN_PARAMS_HPP
 
 namespace Opm {
 /*!
diff --git a/opm/material/fluidstates/CompositionalFluidState.hpp b/opm/material/fluidstates/CompositionalFluidState.hpp
index 82b532a33..89bd32e19 100644
--- a/opm/material/fluidstates/CompositionalFluidState.hpp
+++ b/opm/material/fluidstates/CompositionalFluidState.hpp
@@ -23,8 +23,8 @@
  *        multi-phase, multi-component fluid system assuming
  *        thermodynamic equilibrium.
  */
-#ifndef OPM_COMPOSITIONAL_FLUID_STATE_HH
-#define OPM_COMPOSITIONAL_FLUID_STATE_HH
+#ifndef OPM_COMPOSITIONAL_FLUID_STATE_HPP
+#define OPM_COMPOSITIONAL_FLUID_STATE_HPP
 
 #include "ModularFluidState.hpp"
 
diff --git a/opm/material/fluidstates/FluidStateCompositionModules.hpp b/opm/material/fluidstates/FluidStateCompositionModules.hpp
index 6c3fbdae9..f2fb733c9 100644
--- a/opm/material/fluidstates/FluidStateCompositionModules.hpp
+++ b/opm/material/fluidstates/FluidStateCompositionModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent composition.
  */
-#ifndef OPM_FLUID_STATE_COMPOSITION_MODULES_HH
-#define OPM_FLUID_STATE_COMPOSITION_MODULES_HH
+#ifndef OPM_FLUID_STATE_COMPOSITION_MODULES_HPP
+#define OPM_FLUID_STATE_COMPOSITION_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStateDensityModules.hpp b/opm/material/fluidstates/FluidStateDensityModules.hpp
index da9865461..0b0894938 100644
--- a/opm/material/fluidstates/FluidStateDensityModules.hpp
+++ b/opm/material/fluidstates/FluidStateDensityModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent density.
  */
-#ifndef OPM_FLUID_STATE_DENSITY_MODULES_HH
-#define OPM_FLUID_STATE_DENSITY_MODULES_HH
+#ifndef OPM_FLUID_STATE_DENSITY_MODULES_HPP
+#define OPM_FLUID_STATE_DENSITY_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStateEnthalpyModules.hpp b/opm/material/fluidstates/FluidStateEnthalpyModules.hpp
index 483d418fe..853c5157d 100644
--- a/opm/material/fluidstates/FluidStateEnthalpyModules.hpp
+++ b/opm/material/fluidstates/FluidStateEnthalpyModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent enthalpy.
  */
-#ifndef OPM_FLUID_STATE_ENTHALPY_MODULES_HH
-#define OPM_FLUID_STATE_ENTHALPY_MODULES_HH
+#ifndef OPM_FLUID_STATE_ENTHALPY_MODULES_HPP
+#define OPM_FLUID_STATE_ENTHALPY_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStateFugacityModules.hpp b/opm/material/fluidstates/FluidStateFugacityModules.hpp
index b93f74468..62ae8f894 100644
--- a/opm/material/fluidstates/FluidStateFugacityModules.hpp
+++ b/opm/material/fluidstates/FluidStateFugacityModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent fugacity/chemical potential.
  */
-#ifndef OPM_FLUID_STATE_FUGACITY_MODULES_HH
-#define OPM_FLUID_STATE_FUGACITY_MODULES_HH
+#ifndef OPM_FLUID_STATE_FUGACITY_MODULES_HPP
+#define OPM_FLUID_STATE_FUGACITY_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStatePressureModules.hpp b/opm/material/fluidstates/FluidStatePressureModules.hpp
index 163b5a228..64811b9ce 100644
--- a/opm/material/fluidstates/FluidStatePressureModules.hpp
+++ b/opm/material/fluidstates/FluidStatePressureModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent pressure.
  */
-#ifndef OPM_FLUID_STATE_PRESSURE_MODULES_HH
-#define OPM_FLUID_STATE_PRESSURE_MODULES_HH
+#ifndef OPM_FLUID_STATE_PRESSURE_MODULES_HPP
+#define OPM_FLUID_STATE_PRESSURE_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStateSaturationModules.hpp b/opm/material/fluidstates/FluidStateSaturationModules.hpp
index 95dd77a39..efae73da0 100644
--- a/opm/material/fluidstates/FluidStateSaturationModules.hpp
+++ b/opm/material/fluidstates/FluidStateSaturationModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent saturation.
  */
-#ifndef OPM_FLUID_STATE_SATURATION_MODULES_HH
-#define OPM_FLUID_STATE_SATURATION_MODULES_HH
+#ifndef OPM_FLUID_STATE_SATURATION_MODULES_HPP
+#define OPM_FLUID_STATE_SATURATION_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStateTemperatureModules.hpp b/opm/material/fluidstates/FluidStateTemperatureModules.hpp
index 8c0b7bb21..5215d6d78 100644
--- a/opm/material/fluidstates/FluidStateTemperatureModules.hpp
+++ b/opm/material/fluidstates/FluidStateTemperatureModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent temperature.
  */
-#ifndef OPM_FLUID_STATE_TEMPERATURE_MODULES_HH
-#define OPM_FLUID_STATE_TEMPERATURE_MODULES_HH
+#ifndef OPM_FLUID_STATE_TEMPERATURE_MODULES_HPP
+#define OPM_FLUID_STATE_TEMPERATURE_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/FluidStateViscosityModules.hpp b/opm/material/fluidstates/FluidStateViscosityModules.hpp
index 2420db87b..d9e440d95 100644
--- a/opm/material/fluidstates/FluidStateViscosityModules.hpp
+++ b/opm/material/fluidstates/FluidStateViscosityModules.hpp
@@ -21,8 +21,8 @@
  *
  * \brief Modules for the ModularFluidState which represent viscosity.
  */
-#ifndef OPM_FLUID_STATE_VISCOSITY_MODULES_HH
-#define OPM_FLUID_STATE_VISCOSITY_MODULES_HH
+#ifndef OPM_FLUID_STATE_VISCOSITY_MODULES_HPP
+#define OPM_FLUID_STATE_VISCOSITY_MODULES_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/ImmiscibleFluidState.hpp b/opm/material/fluidstates/ImmiscibleFluidState.hpp
index 48917c10c..e159a6d4b 100644
--- a/opm/material/fluidstates/ImmiscibleFluidState.hpp
+++ b/opm/material/fluidstates/ImmiscibleFluidState.hpp
@@ -23,8 +23,8 @@
  *        multi-phase, multi-component fluid system assuming
  *        thermodynamic equilibrium.
  */
-#ifndef OPM_IMMISCIBLE_FLUID_STATE_HH
-#define OPM_IMMISCIBLE_FLUID_STATE_HH
+#ifndef OPM_IMMISCIBLE_FLUID_STATE_HPP
+#define OPM_IMMISCIBLE_FLUID_STATE_HPP
 
 #include "ModularFluidState.hpp"
 
diff --git a/opm/material/fluidstates/ModularFluidState.hpp b/opm/material/fluidstates/ModularFluidState.hpp
index 88aac1890..b4eed1dc2 100644
--- a/opm/material/fluidstates/ModularFluidState.hpp
+++ b/opm/material/fluidstates/ModularFluidState.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::ModularFluidState
  */
-#ifndef OPM_MODULAR_FLUID_STATE_HH
-#define OPM_MODULAR_FLUID_STATE_HH
+#ifndef OPM_MODULAR_FLUID_STATE_HPP
+#define OPM_MODULAR_FLUID_STATE_HPP
 
 #include "FluidStatePressureModules.hpp"
 #include "FluidStateTemperatureModules.hpp"
diff --git a/opm/material/fluidstates/NonEquilibriumFluidState.hpp b/opm/material/fluidstates/NonEquilibriumFluidState.hpp
index 7092fce61..38890c63b 100644
--- a/opm/material/fluidstates/NonEquilibriumFluidState.hpp
+++ b/opm/material/fluidstates/NonEquilibriumFluidState.hpp
@@ -23,8 +23,8 @@
  *        multi-phase, multi-component fluid system _not_ assuming
  *        thermodynamic equilibrium.
  */
-#ifndef OPM_NON_EQUILIBRIUM_FLUID_STATE_HH
-#define OPM_NON_EQUILIBRIUM_FLUID_STATE_HH
+#ifndef OPM_NON_EQUILIBRIUM_FLUID_STATE_HPP
+#define OPM_NON_EQUILIBRIUM_FLUID_STATE_HPP
 
 #include "ModularFluidState.hpp"
 
diff --git a/opm/material/fluidstates/PressureOverlayFluidState.hpp b/opm/material/fluidstates/PressureOverlayFluidState.hpp
index 3abdd7311..d1798c29b 100644
--- a/opm/material/fluidstates/PressureOverlayFluidState.hpp
+++ b/opm/material/fluidstates/PressureOverlayFluidState.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::PressureOverlayFluidState
  */
-#ifndef OPM_PRESSURE_OVERLAY_FLUID_STATE_HH
-#define OPM_PRESSURE_OVERLAY_FLUID_STATE_HH
+#ifndef OPM_PRESSURE_OVERLAY_FLUID_STATE_HPP
+#define OPM_PRESSURE_OVERLAY_FLUID_STATE_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/SaturationOverlayFluidState.hpp b/opm/material/fluidstates/SaturationOverlayFluidState.hpp
index 0d456f82d..979cfdef1 100644
--- a/opm/material/fluidstates/SaturationOverlayFluidState.hpp
+++ b/opm/material/fluidstates/SaturationOverlayFluidState.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::SaturationOverlayFluidState
  */
-#ifndef OPM_SATURATION_OVERLAY_FLUID_STATE_HH
-#define OPM_SATURATION_OVERLAY_FLUID_STATE_HH
+#ifndef OPM_SATURATION_OVERLAY_FLUID_STATE_HPP
+#define OPM_SATURATION_OVERLAY_FLUID_STATE_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidstates/TemperatureOverlayFluidState.hpp b/opm/material/fluidstates/TemperatureOverlayFluidState.hpp
index a59948389..b85386578 100644
--- a/opm/material/fluidstates/TemperatureOverlayFluidState.hpp
+++ b/opm/material/fluidstates/TemperatureOverlayFluidState.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::TemperatureOverlayFluidState
  */
-#ifndef OPM_TEMPERATURE_OVERLAY_FLUID_STATE_HH
-#define OPM_TEMPERATURE_OVERLAY_FLUID_STATE_HH
+#ifndef OPM_TEMPERATURE_OVERLAY_FLUID_STATE_HPP
+#define OPM_TEMPERATURE_OVERLAY_FLUID_STATE_HPP
 
 #include <opm/material/Valgrind.hpp>
 
diff --git a/opm/material/fluidsystems/1pFluidSystem.hpp b/opm/material/fluidsystems/1pFluidSystem.hpp
index 4287621bb..f25cfd63c 100644
--- a/opm/material/fluidsystems/1pFluidSystem.hpp
+++ b/opm/material/fluidsystems/1pFluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidSystems::OneP
  */
-#ifndef OPM_1P_FLUIDSYSTEM_HH
-#define OPM_1P_FLUIDSYSTEM_HH
+#ifndef OPM_1P_FLUIDSYSTEM_HPP
+#define OPM_1P_FLUIDSYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "NullParameterCache.hpp"
diff --git a/opm/material/fluidsystems/2pImmiscibleFluidSystem.hpp b/opm/material/fluidsystems/2pImmiscibleFluidSystem.hpp
index 9bfee7b9c..122f27797 100644
--- a/opm/material/fluidsystems/2pImmiscibleFluidSystem.hpp
+++ b/opm/material/fluidsystems/2pImmiscibleFluidSystem.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::FluidSystems::TwoPImmiscible
  */
-#ifndef OPM_2P_IMMISCIBLE_FLUID_SYSTEM_HH
-#define OPM_2P_IMMISCIBLE_FLUID_SYSTEM_HH
+#ifndef OPM_2P_IMMISCIBLE_FLUID_SYSTEM_HPP
+#define OPM_2P_IMMISCIBLE_FLUID_SYSTEM_HPP
 
 #include <limits>
 #include <cassert>
diff --git a/opm/material/fluidsystems/BaseFluidSystem.hpp b/opm/material/fluidsystems/BaseFluidSystem.hpp
index aa66bc60f..38f8b97e6 100644
--- a/opm/material/fluidsystems/BaseFluidSystem.hpp
+++ b/opm/material/fluidsystems/BaseFluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::BaseFluidSystem
  */
-#ifndef OPM_BASE_FLUID_SYSTEM_HH
-#define OPM_BASE_FLUID_SYSTEM_HH
+#ifndef OPM_BASE_FLUID_SYSTEM_HPP
+#define OPM_BASE_FLUID_SYSTEM_HPP
 
 #include "NullParameterCache.hpp"
 
diff --git a/opm/material/fluidsystems/BlackOilFluidSystem.hpp b/opm/material/fluidsystems/BlackOilFluidSystem.hpp
index 46c85a1d5..db86a8a98 100644
--- a/opm/material/fluidsystems/BlackOilFluidSystem.hpp
+++ b/opm/material/fluidsystems/BlackOilFluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidSystems::BlackOil
  */
-#ifndef OPM_BLACK_OIL_FLUID_SYSTEM_HH
-#define OPM_BLACK_OIL_FLUID_SYSTEM_HH
+#ifndef OPM_BLACK_OIL_FLUID_SYSTEM_HPP
+#define OPM_BLACK_OIL_FLUID_SYSTEM_HPP
 
 #include <opm/core/utility/Exceptions.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
diff --git a/opm/material/fluidsystems/BrineCO2FluidSystem.hpp b/opm/material/fluidsystems/BrineCO2FluidSystem.hpp
index b45798d0c..22667ee73 100644
--- a/opm/material/fluidsystems/BrineCO2FluidSystem.hpp
+++ b/opm/material/fluidsystems/BrineCO2FluidSystem.hpp
@@ -21,8 +21,8 @@
  *
  * \copydoc Opm::FluidSystems::BrineCO2
  */
-#ifndef OPM_BRINE_CO2_SYSTEM_HH
-#define OPM_BRINE_CO2_SYSTEM_HH
+#ifndef OPM_BRINE_CO2_SYSTEM_HPP
+#define OPM_BRINE_CO2_SYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "NullParameterCache.hpp"
diff --git a/opm/material/fluidsystems/GasPhase.hpp b/opm/material/fluidsystems/GasPhase.hpp
index 4077c8862..949d1eeef 100644
--- a/opm/material/fluidsystems/GasPhase.hpp
+++ b/opm/material/fluidsystems/GasPhase.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::GasPhase
  */
-#ifndef OPM_GAS_PHASE_HH
-#define OPM_GAS_PHASE_HH
+#ifndef OPM_GAS_PHASE_HPP
+#define OPM_GAS_PHASE_HPP
 
 namespace Opm {
 
diff --git a/opm/material/fluidsystems/H2OAirFluidSystem.hpp b/opm/material/fluidsystems/H2OAirFluidSystem.hpp
index 509147e46..33a6cb3f4 100644
--- a/opm/material/fluidsystems/H2OAirFluidSystem.hpp
+++ b/opm/material/fluidsystems/H2OAirFluidSystem.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::FluidSystems::H2OAir
  */
-#ifndef OPM_H2O_AIR_SYSTEM_HH
-#define OPM_H2O_AIR_SYSTEM_HH
+#ifndef OPM_H2O_AIR_SYSTEM_HPP
+#define OPM_H2O_AIR_SYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "NullParameterCache.hpp"
diff --git a/opm/material/fluidsystems/H2OAirMesityleneFluidSystem.hpp b/opm/material/fluidsystems/H2OAirMesityleneFluidSystem.hpp
index 37a0e8bfc..461d464e0 100644
--- a/opm/material/fluidsystems/H2OAirMesityleneFluidSystem.hpp
+++ b/opm/material/fluidsystems/H2OAirMesityleneFluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidSystems::H2OAirMesitylene
  */
-#ifndef OPM_H2O_AIR_MESITYLENE_FLUID_SYSTEM_HH
-#define OPM_H2O_AIR_MESITYLENE_FLUID_SYSTEM_HH
+#ifndef OPM_H2O_AIR_MESITYLENE_FLUID_SYSTEM_HPP
+#define OPM_H2O_AIR_MESITYLENE_FLUID_SYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "NullParameterCache.hpp"
diff --git a/opm/material/fluidsystems/H2OAirXyleneFluidSystem.hpp b/opm/material/fluidsystems/H2OAirXyleneFluidSystem.hpp
index ec2899032..4d79ef5dc 100644
--- a/opm/material/fluidsystems/H2OAirXyleneFluidSystem.hpp
+++ b/opm/material/fluidsystems/H2OAirXyleneFluidSystem.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::FluidSystems::H2OAirXylene
  */
-#ifndef OPM_H2O_AIR_XYLENE_FLUID_SYSTEM_HH
-#define OPM_H2O_AIR_XYLENE_FLUID_SYSTEM_HH
+#ifndef OPM_H2O_AIR_XYLENE_FLUID_SYSTEM_HPP
+#define OPM_H2O_AIR_XYLENE_FLUID_SYSTEM_HPP
 
 #include <opm/material/IdealGas.hpp>
 #include <opm/material/components/Air.hpp>
diff --git a/opm/material/fluidsystems/H2ON2FluidSystem.hpp b/opm/material/fluidsystems/H2ON2FluidSystem.hpp
index 7b428335e..d3c8bd5a7 100644
--- a/opm/material/fluidsystems/H2ON2FluidSystem.hpp
+++ b/opm/material/fluidsystems/H2ON2FluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidSystems::H2ON2
  */
-#ifndef OPM_H2O_N2_FLUID_SYSTEM_HH
-#define OPM_H2O_N2_FLUID_SYSTEM_HH
+#ifndef OPM_H2O_N2_FLUID_SYSTEM_HPP
+#define OPM_H2O_N2_FLUID_SYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "NullParameterCache.hpp"
diff --git a/opm/material/fluidsystems/H2ON2LiquidPhaseFluidSystem.hpp b/opm/material/fluidsystems/H2ON2LiquidPhaseFluidSystem.hpp
index 4dd2e44f5..b5ea02be2 100644
--- a/opm/material/fluidsystems/H2ON2LiquidPhaseFluidSystem.hpp
+++ b/opm/material/fluidsystems/H2ON2LiquidPhaseFluidSystem.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::FluidSystems::H2ON2LiquidPhase
  */
-#ifndef OPM_H2O_N2_LIQUIDPHASE_FLUID_SYSTEM_HH
-#define OPM_H2O_N2_LIQUIDPHASE_FLUID_SYSTEM_HH
+#ifndef OPM_H2O_N2_LIQUIDPHASE_FLUID_SYSTEM_HPP
+#define OPM_H2O_N2_LIQUIDPHASE_FLUID_SYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "NullParameterCache.hpp"
diff --git a/opm/material/fluidsystems/LiquidPhase.hpp b/opm/material/fluidsystems/LiquidPhase.hpp
index f85af4c53..24edcac46 100644
--- a/opm/material/fluidsystems/LiquidPhase.hpp
+++ b/opm/material/fluidsystems/LiquidPhase.hpp
@@ -21,8 +21,8 @@
  * \file
  * \copydoc Opm::LiquidPhase
  */
-#ifndef OPM_LIQUID_PHASE_HH
-#define OPM_LIQUID_PHASE_HH
+#ifndef OPM_LIQUID_PHASE_HPP
+#define OPM_LIQUID_PHASE_HPP
 
 namespace Opm {
 
diff --git a/opm/material/fluidsystems/NullParameterCache.hpp b/opm/material/fluidsystems/NullParameterCache.hpp
index 79f238f5a..c7da4e9f9 100644
--- a/opm/material/fluidsystems/NullParameterCache.hpp
+++ b/opm/material/fluidsystems/NullParameterCache.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::NullParameterCache
  */
-#ifndef OPM_NULL_PARAMETER_CACHE_HH
-#define OPM_NULL_PARAMETER_CACHE_HH
+#ifndef OPM_NULL_PARAMETER_CACHE_HPP
+#define OPM_NULL_PARAMETER_CACHE_HPP
 
 #include "ParameterCacheBase.hpp"
 
diff --git a/opm/material/fluidsystems/ParameterCacheBase.hpp b/opm/material/fluidsystems/ParameterCacheBase.hpp
index c7ace569f..c68762124 100644
--- a/opm/material/fluidsystems/ParameterCacheBase.hpp
+++ b/opm/material/fluidsystems/ParameterCacheBase.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::ParameterCacheBase
  */
-#ifndef OPM_PARAMETER_CACHE_BASE_HH
-#define OPM_PARAMETER_CACHE_BASE_HH
+#ifndef OPM_PARAMETER_CACHE_BASE_HPP
+#define OPM_PARAMETER_CACHE_BASE_HPP
 
 namespace Opm {
 
diff --git a/opm/material/fluidsystems/Spe5FluidSystem.hpp b/opm/material/fluidsystems/Spe5FluidSystem.hpp
index 3cb98e47a..0846321fd 100644
--- a/opm/material/fluidsystems/Spe5FluidSystem.hpp
+++ b/opm/material/fluidsystems/Spe5FluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidSystems::Spe5
  */
-#ifndef OPM_SPE5_FLUID_SYSTEM_HH
-#define OPM_SPE5_FLUID_SYSTEM_HH
+#ifndef OPM_SPE5_FLUID_SYSTEM_HPP
+#define OPM_SPE5_FLUID_SYSTEM_HPP
 
 #include "BaseFluidSystem.hpp"
 #include "Spe5ParameterCache.hpp"
diff --git a/opm/material/fluidsystems/Spe5ParameterCache.hpp b/opm/material/fluidsystems/Spe5ParameterCache.hpp
index f9b8c4091..c8de29ab2 100644
--- a/opm/material/fluidsystems/Spe5ParameterCache.hpp
+++ b/opm/material/fluidsystems/Spe5ParameterCache.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::Spe5ParameterCache
  */
-#ifndef OPM_SPE5_PARAMETER_CACHE_HH
-#define OPM_SPE5_PARAMETER_CACHE_HH
+#ifndef OPM_SPE5_PARAMETER_CACHE_HPP
+#define OPM_SPE5_PARAMETER_CACHE_HPP
 
 #include <cassert>
 
diff --git a/opm/material/heatconduction/DummyHeatConductionLaw.hpp b/opm/material/heatconduction/DummyHeatConductionLaw.hpp
index 8179a2dc3..c074112ed 100644
--- a/opm/material/heatconduction/DummyHeatConductionLaw.hpp
+++ b/opm/material/heatconduction/DummyHeatConductionLaw.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::DummyHeatConductionLaw
  */
-#ifndef OPM_DUMMY_HEATCONDUCTION_LAW_HH
-#define OPM_DUMMY_HEATCONDUCTION_LAW_HH
+#ifndef OPM_DUMMY_HEATCONDUCTION_LAW_HPP
+#define OPM_DUMMY_HEATCONDUCTION_LAW_HPP
 
 #include <opm/core/utility/Exceptions.hpp>
 #include <opm/core/utility/ErrorMacros.hpp>
diff --git a/opm/material/heatconduction/FluidConduction.hpp b/opm/material/heatconduction/FluidConduction.hpp
index c4fb9a41c..e5da0e6a9 100644
--- a/opm/material/heatconduction/FluidConduction.hpp
+++ b/opm/material/heatconduction/FluidConduction.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidHeatConduction
  */
-#ifndef OPM_FLUID_HEAT_CONDUCTION_HH
-#define OPM_FLUID_HEAT_CONDUCTION_HH
+#ifndef OPM_FLUID_HEAT_CONDUCTION_HPP
+#define OPM_FLUID_HEAT_CONDUCTION_HPP
 
 #include "FluidConductionParams.hpp"
 
diff --git a/opm/material/heatconduction/FluidConductionParams.hpp b/opm/material/heatconduction/FluidConductionParams.hpp
index cf92016c7..15e2695fc 100644
--- a/opm/material/heatconduction/FluidConductionParams.hpp
+++ b/opm/material/heatconduction/FluidConductionParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::FluidHeatConductionParams
  */
-#ifndef OPM_FLUID_HEAT_CONDUCTION_PARAMS_HH
-#define OPM_FLUID_HEAT_CONDUCTION_PARAMS_HH
+#ifndef OPM_FLUID_HEAT_CONDUCTION_PARAMS_HPP
+#define OPM_FLUID_HEAT_CONDUCTION_PARAMS_HPP
 
 namespace Opm {
 /*!
diff --git a/opm/material/heatconduction/Somerton.hpp b/opm/material/heatconduction/Somerton.hpp
index 66984e880..fdc3ff565 100644
--- a/opm/material/heatconduction/Somerton.hpp
+++ b/opm/material/heatconduction/Somerton.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::Somerton
  */
-#ifndef OPM_SOMERTON_HH
-#define OPM_SOMERTON_HH
+#ifndef OPM_SOMERTON_HPP
+#define OPM_SOMERTON_HPP
 
 #include "SomertonParams.hpp"
 
diff --git a/opm/material/heatconduction/SomertonParams.hpp b/opm/material/heatconduction/SomertonParams.hpp
index 8927e4047..8ac4de49a 100644
--- a/opm/material/heatconduction/SomertonParams.hpp
+++ b/opm/material/heatconduction/SomertonParams.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc Opm::SomertonParams
  */
-#ifndef OPM_SOMERTON_PARAMS_HH
-#define OPM_SOMERTON_PARAMS_HH
+#ifndef OPM_SOMERTON_PARAMS_HPP
+#define OPM_SOMERTON_PARAMS_HPP
 
 #include <cassert>
 
diff --git a/tests/checkFluidSystem.hpp b/tests/checkFluidSystem.hpp
index 905f46676..66f940b41 100644
--- a/tests/checkFluidSystem.hpp
+++ b/tests/checkFluidSystem.hpp
@@ -20,8 +20,8 @@
  * \file
  * \copydoc checkFluidSystem
  */
-#ifndef OPM_CHECK_FLUIDSYSTEM_HH
-#define OPM_CHECK_FLUIDSYSTEM_HH
+#ifndef OPM_CHECK_FLUIDSYSTEM_HPP
+#define OPM_CHECK_FLUIDSYSTEM_HPP
 
 // include all fluid systems in opm-material
 #include <opm/material/fluidsystems/1pFluidSystem.hpp>