diff --git a/applications/utilities/miscellaneous/foamFormatConvert/foamFormatConvert.C b/applications/utilities/miscellaneous/foamFormatConvert/foamFormatConvert.C
index e95503d021..443d4d32d8 100644
--- a/applications/utilities/miscellaneous/foamFormatConvert/foamFormatConvert.C
+++ b/applications/utilities/miscellaneous/foamFormatConvert/foamFormatConvert.C
@@ -218,7 +218,7 @@ bool writeOptionalMeshObject
     );
 
     bool writeOk = false;
-    const bool haveFile = io.typeHeaderOk<IOField<label>>(false);
+    const bool haveFile = io.typeHeaderOk<regIOobject>(false);
 
     // Make sure all know if there is a valid class name
     wordList classNames(1, io.headerClassName());
@@ -375,41 +375,41 @@ int main(int argc, char *argv[])
 
         forAllConstIters(objects, iter)
         {
-            const word& headerClassName = (*iter)->headerClassName();
+            const IOobject& io = *(iter.val());
 
             if
             (
-                headerClassName == volScalarField::typeName
-             || headerClassName == volVectorField::typeName
-             || headerClassName == volSphericalTensorField::typeName
-             || headerClassName == volSymmTensorField::typeName
-             || headerClassName == volTensorField::typeName
+                io.isHeaderClass<volScalarField>()
+             || io.isHeaderClass<volVectorField>()
+             || io.isHeaderClass<volSphericalTensorField>()
+             || io.isHeaderClass<volSymmTensorField>()
+             || io.isHeaderClass<volTensorField>()
 
-             || headerClassName == surfaceScalarField::typeName
-             || headerClassName == surfaceVectorField::typeName
-             || headerClassName == surfaceSphericalTensorField::typeName
-             || headerClassName == surfaceSymmTensorField::typeName
-             || headerClassName == surfaceTensorField::typeName
+             || io.isHeaderClass<surfaceScalarField>()
+             || io.isHeaderClass<surfaceVectorField>()
+             || io.isHeaderClass<surfaceSphericalTensorField>()
+             || io.isHeaderClass<surfaceSymmTensorField>()
+             || io.isHeaderClass<surfaceTensorField>()
 
-             || headerClassName == pointScalarField::typeName
-             || headerClassName == pointVectorField::typeName
-             || headerClassName == pointSphericalTensorField::typeName
-             || headerClassName == pointSymmTensorField::typeName
-             || headerClassName == pointTensorField::typeName
+             || io.isHeaderClass<pointScalarField>()
+             || io.isHeaderClass<pointVectorField>()
+             || io.isHeaderClass<pointSphericalTensorField>()
+             || io.isHeaderClass<pointSymmTensorField>()
+             || io.isHeaderClass<pointTensorField>()
 
-             || headerClassName == volScalarField::Internal::typeName
-             || headerClassName == volVectorField::Internal::typeName
-             || headerClassName == volSphericalTensorField::Internal::typeName
-             || headerClassName == volSymmTensorField::Internal::typeName
-             || headerClassName == volTensorField::Internal::typeName
+             || io.isHeaderClass<volScalarField::Internal>()
+             || io.isHeaderClass<volVectorField::Internal>()
+             || io.isHeaderClass<volSphericalTensorField::Internal>()
+             || io.isHeaderClass<volSymmTensorField::Internal>()
+             || io.isHeaderClass<volTensorField::Internal>()
             )
             {
-                Info<< "        Reading " << headerClassName
-                    << " : " << (*iter)->name() << endl;
+                Info<< "        Reading " << io.headerClassName()
+                    << " : " << io.name() << endl;
 
-                fieldDictionary fDict(*iter(), headerClassName);
+                fieldDictionary fDict(io, io.headerClassName());
 
-                Info<< "        Writing " << (*iter)->name() << endl;
+                Info<< "        Writing " << io.name() << endl;
                 fDict.regIOobject::write();
             }
         }
diff --git a/applications/utilities/miscellaneous/foamHelp/helpTypes/helpBoundary/helpBoundaryTemplates.C b/applications/utilities/miscellaneous/foamHelp/helpTypes/helpBoundary/helpBoundaryTemplates.C
index 9a51d225f7..b528954050 100644
--- a/applications/utilities/miscellaneous/foamHelp/helpTypes/helpBoundary/helpBoundaryTemplates.C
+++ b/applications/utilities/miscellaneous/foamHelp/helpTypes/helpBoundary/helpBoundaryTemplates.C
@@ -39,9 +39,9 @@ Foam::wordList Foam::helpTypes::helpBoundary::fieldConditions
     const bool write
 ) const
 {
-    typedef GeometricField<Type, fvPatchField, volMesh> fieldType;
+    typedef GeometricField<Type, fvPatchField, volMesh> VolFieldType;
 
-    if (io.headerClassName() == fieldType::typeName)
+    if (io.isHeaderClass<VolFieldType>())
     {
         wordList types
         (
@@ -74,6 +74,8 @@ void Foam::helpTypes::helpBoundary::fixedValueFieldConditions
     const IOobject& io
 ) const
 {
+    typedef GeometricField<Type, fvPatchField, volMesh> VolFieldType;
+
     wordList types(fieldConditions<Type>(io, false));
 
     if (!types.size())
@@ -81,11 +83,9 @@ void Foam::helpTypes::helpBoundary::fixedValueFieldConditions
         return;
     }
 
-    typedef GeometricField<Type, fvPatchField, volMesh> fieldType;
-
     const fvMesh& mesh = dynamic_cast<const fvMesh&>(io.db());
 
-    fieldType fld
+    VolFieldType fld
     (
         IOobject
         (
diff --git a/applications/utilities/miscellaneous/patchSummary/patchSummaryTemplates.C b/applications/utilities/miscellaneous/patchSummary/patchSummaryTemplates.C
index 1eb569fa57..96ec1ead4e 100644
--- a/applications/utilities/miscellaneous/patchSummary/patchSummaryTemplates.C
+++ b/applications/utilities/miscellaneous/patchSummary/patchSummaryTemplates.C
@@ -39,7 +39,7 @@ void Foam::addToFieldList
     const typename GeoField::Mesh& mesh
 )
 {
-    if (obj.headerClassName() == GeoField::typeName)
+    if (obj.isHeaderClass<GeoField>())
     {
         fieldList.set
         (
diff --git a/applications/utilities/postProcessing/lagrangian/steadyParticleTracks/steadyParticleTracks.C b/applications/utilities/postProcessing/lagrangian/steadyParticleTracks/steadyParticleTracks.C
index ba7aa1c56f..bde1b627af 100644
--- a/applications/utilities/postProcessing/lagrangian/steadyParticleTracks/steadyParticleTracks.C
+++ b/applications/utilities/postProcessing/lagrangian/steadyParticleTracks/steadyParticleTracks.C
@@ -107,12 +107,12 @@ IOobjectList preFilterFields
             if
             (
                 //OR: fieldTypes::basic.found(io.headerClassName())
-                io.headerClassName() == IOField<label>::typeName
-             || io.headerClassName() == IOField<scalar>::typeName
-             || io.headerClassName() == IOField<vector>::typeName
-             || io.headerClassName() == IOField<sphericalTensor>::typeName
-             || io.headerClassName() == IOField<symmTensor>::typeName
-             || io.headerClassName() == IOField<tensor>::typeName
+                io.isHeaderClass<IOField<label>>()
+             || io.isHeaderClass<IOField<scalar>>()
+             || io.isHeaderClass<IOField<vector>>()
+             || io.isHeaderClass<IOField<sphericalTensor>>()
+             || io.isHeaderClass<IOField<symmTensor>>()
+             || io.isHeaderClass<IOField<tensor>>()
             )
             {
                 // Transfer from cloudObjects -> filteredObjects
diff --git a/applications/utilities/postProcessing/lumped/lumpedPointForces/lumpedPointForces.C b/applications/utilities/postProcessing/lumped/lumpedPointForces/lumpedPointForces.C
index 0ba2b9a0b3..86d43bd3bb 100644
--- a/applications/utilities/postProcessing/lumped/lumpedPointForces/lumpedPointForces.C
+++ b/applications/utilities/postProcessing/lumped/lumpedPointForces/lumpedPointForces.C
@@ -52,9 +52,9 @@ autoPtr<GeoFieldType> loadField
     const IOobject* io
 )
 {
-    if (io && io->headerClassName() == GeoFieldType::typeName)
+    if (io && io->isHeaderClass<GeoFieldType>())
     {
-        Info<< "Reading " << GeoFieldType::typeName
+        Info<< "Reading " << io->headerClassName()
             << ' ' << io->name() << endl;
 
         return autoPtr<GeoFieldType>::New
diff --git a/applications/utilities/preProcessing/setExprBoundaryFields/readFields.H b/applications/utilities/preProcessing/setExprBoundaryFields/readFields.H
index ae294ebc27..07e0bb443e 100644
--- a/applications/utilities/preProcessing/setExprBoundaryFields/readFields.H
+++ b/applications/utilities/preProcessing/setExprBoundaryFields/readFields.H
@@ -121,15 +121,14 @@ class readFieldsHandler
                 (
                     fieldName,
                     mesh_.time().timeName(),
-                    mesh_,
+                    mesh_.thisDb(),
                     IOobject::MUST_READ,
                     IOobject::NO_WRITE
                 );
 
                 const bool ok =
                 (
-                    io.typeHeaderOk<regIOobject>(false) // Preload header info
-                 && io.hasHeaderClass()                 // Extra safety
+                    io.typeHeaderOk<regIOobject>(false)
                  &&
                     (
                         loadField<scalar>(io)
diff --git a/applications/utilities/preProcessing/setExprFields/readFields.H b/applications/utilities/preProcessing/setExprFields/readFields.H
index 2eb63699ba..8ab2063ed9 100644
--- a/applications/utilities/preProcessing/setExprFields/readFields.H
+++ b/applications/utilities/preProcessing/setExprFields/readFields.H
@@ -121,15 +121,14 @@ class readFieldsHandler
                 (
                     fieldName,
                     mesh_.time().timeName(),
-                    mesh_,
+                    mesh_.thisDb(),
                     IOobject::MUST_READ,
                     IOobject::NO_WRITE
                 );
 
                 const bool ok =
                 (
-                    io.typeHeaderOk<regIOobject>(false) // Preload header info
-                 && io.hasHeaderClass()                 // Extra safety
+                    io.typeHeaderOk<regIOobject>(false)
                  &&
                     (
                         loadField<scalar>(io)
diff --git a/applications/utilities/preProcessing/setExprFields/setExprFields.C b/applications/utilities/preProcessing/setExprFields/setExprFields.C
index 9704b34ab0..59c180c551 100644
--- a/applications/utilities/preProcessing/setExprFields/setExprFields.C
+++ b/applications/utilities/preProcessing/setExprFields/setExprFields.C
@@ -270,9 +270,8 @@ void evaluate
             IOobject::MUST_READ,
             IOobject::NO_WRITE
         );
-        io.typeHeaderOk<IOobject>(false);
 
-        if (!io.hasHeaderClass() || io.isHeaderClass<IOobject>())
+        if (!io.typeHeaderOk<regIOobject>(false))
         {
             FatalErrorInFunction
                 << "Field '" << fieldName
diff --git a/src/OpenFOAM/db/IOobjectList/IOobjectList.C b/src/OpenFOAM/db/IOobjectList/IOobjectList.C
index 9cf21f9022..8ae7d52a5f 100644
--- a/src/OpenFOAM/db/IOobjectList/IOobjectList.C
+++ b/src/OpenFOAM/db/IOobjectList/IOobjectList.C
@@ -28,7 +28,6 @@ License
 
 #include "IOobjectList.H"
 #include "Time.H"
-#include "IOList.H"
 #include "predicates.H"
 #include "OSspecific.H"
 
@@ -135,7 +134,7 @@ Foam::IOobjectList::IOobjectList
         try
         {
             // Use object with local scope and current instance (no searching)
-            ok = objectPtr->typeHeaderOk<IOList<label>>(false, false);
+            ok = objectPtr->typeHeaderOk<regIOobject>(false, false);
         }
         catch (const Foam::IOerror& err)
         {
diff --git a/src/finiteVolume/expressions/base/fvExprDriverIO.C b/src/finiteVolume/expressions/base/fvExprDriverIO.C
index 323de163e3..500ac1c772 100644
--- a/src/finiteVolume/expressions/base/fvExprDriverIO.C
+++ b/src/finiteVolume/expressions/base/fvExprDriverIO.C
@@ -199,7 +199,7 @@ Foam::word Foam::expressions::fvExprDriver::getHeaderClassName
         IOobject::MUST_READ,
         IOobject::NO_WRITE
     );
-    io.typeHeaderOk<IOobject>(false);
+    io.typeHeaderOk<regIOobject>(false);
 
     DebugInfo
         << "Registry: " << mesh.path()
diff --git a/src/functionObjects/field/expressions/fvExpressionField.C b/src/functionObjects/field/expressions/fvExpressionField.C
index df11c2e10d..7b3444f6f8 100644
--- a/src/functionObjects/field/expressions/fvExpressionField.C
+++ b/src/functionObjects/field/expressions/fvExpressionField.C
@@ -191,8 +191,7 @@ Foam::label Foam::functionObjects::fvExpressionField::loadFields
 
         const bool ok =
         (
-            io.typeHeaderOk<regIOobject>(false) // Preload header info
-         && io.hasHeaderClass()                 // Extra safety
+            io.typeHeaderOk<regIOobject>(false)
          &&
             (
                 loadField<scalar>(io)
diff --git a/src/functionObjects/field/readFields/readFields.C b/src/functionObjects/field/readFields/readFields.C
index ccd549b180..571c6ad59a 100644
--- a/src/functionObjects/field/readFields/readFields.C
+++ b/src/functionObjects/field/readFields/readFields.C
@@ -117,8 +117,7 @@ bool Foam::functionObjects::readFields::execute()
 
         const bool ok =
         (
-            io.typeHeaderOk<regIOobject>(false) // Preload header info
-         && io.hasHeaderClass()                 // Extra safety
+            io.typeHeaderOk<regIOobject>(false)
          &&
             (
                 loadField<scalar>(io)
diff --git a/src/functionObjects/field/readFields/readFieldsTemplates.C b/src/functionObjects/field/readFields/readFieldsTemplates.C
index 42415c4c56..2ce668755f 100644
--- a/src/functionObjects/field/readFields/readFieldsTemplates.C
+++ b/src/functionObjects/field/readFields/readFieldsTemplates.C
@@ -36,11 +36,11 @@ License
 template<class FieldType>
 bool Foam::functionObjects::readFields::loadAndStore(const IOobject& io)
 {
-    if (FieldType::typeName == io.headerClassName())
+    if (io.isHeaderClass<FieldType>())
     {
         // Store field on mesh database
         Log << "    Reading " << io.name()
-            << " (" << FieldType::typeName << ')' << endl;
+            << " (" << io.headerClassName() << ')' << endl;
 
         mesh_.objectRegistry::store(new FieldType(io, mesh_));
         return true;
diff --git a/src/lagrangian/basic/Cloud/CloudIO.C b/src/lagrangian/basic/Cloud/CloudIO.C
index ad8d0574ea..42ceecd762 100644
--- a/src/lagrangian/basic/Cloud/CloudIO.C
+++ b/src/lagrangian/basic/Cloud/CloudIO.C
@@ -251,7 +251,7 @@ bool Foam::Cloud<ParticleType>::readStoreFile
     const IOobject& ioNew
 ) const
 {
-    if (io.headerClassName() == IOField<Type>::typeName)
+    if (io.isHeaderClass<IOField<Type>>())
     {
         IOField<Type> fld(io);
         auto* fldNewPtr = new IOField<Type>(ioNew, std::move(fld));
diff --git a/src/lumpedPointMotion/tools/lumpedPointTools.C b/src/lumpedPointMotion/tools/lumpedPointTools.C
index d58b0c4420..eba1d49d05 100644
--- a/src/lumpedPointMotion/tools/lumpedPointTools.C
+++ b/src/lumpedPointMotion/tools/lumpedPointTools.C
@@ -35,38 +35,40 @@ License
 
 namespace Foam
 {
-    template<class GeoFieldType>
-    static autoPtr<GeoFieldType> loadPointField
-    (
-        const pointMesh::Mesh& mesh,
-        const IOobject* io
-    )
+
+template<class GeoFieldType>
+static autoPtr<GeoFieldType> loadPointField
+(
+    const pointMesh::Mesh& mesh,
+    const IOobject* io
+)
+{
+    if (io && io->isHeaderClass<GeoFieldType>())
     {
-        if (io && io->headerClassName() == GeoFieldType::typeName)
-        {
-            Info<< "Reading " << GeoFieldType::typeName
-                << ' ' << io->name() << endl;
+        Info<< "Reading " << io->headerClassName()
+            << ' ' << io->name() << endl;
 
-            return autoPtr<GeoFieldType>::New
+        return autoPtr<GeoFieldType>::New
+        (
+            IOobject
             (
-                IOobject
-                (
-                    io->name(),
-                    io->instance(),
-                    io->local(),
-                    io->db(),
-                    IOobject::MUST_READ,
-                    IOobject::AUTO_WRITE,
-                    io->registerObject()
-                ),
-                mesh
-            );
-        }
-
-        return nullptr;
+                io->name(),
+                io->instance(),
+                io->local(),
+                io->db(),
+                IOobject::MUST_READ,
+                IOobject::AUTO_WRITE,
+                io->registerObject()
+            ),
+            mesh
+        );
     }
+
+    return nullptr;
 }
 
+} // End namespace Foam
+
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //