diff --git a/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.C b/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.C
index 7670cb5b98..93f8eb8bfd 100644
--- a/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.C
+++ b/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2017 OpenFOAM Foundation
+    Copyright (C) 2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -37,13 +38,7 @@ namespace Foam
 namespace fv
 {
     defineTypeNameAndDebug(radiation, 0);
-
-    addToRunTimeSelectionTable
-    (
-        option,
-        radiation,
-        dictionary
-    );
+    addToRunTimeSelectionTable(option, radiation, dictionary);
 }
 }
 
@@ -60,8 +55,7 @@ Foam::fv::radiation::radiation
 :
     option(sourceName, modelType, dict, mesh)
 {
-    const basicThermo& thermo =
-        mesh_.lookupObject<basicThermo>(basicThermo::dictName);
+    const auto& thermo = mesh_.lookupObject<basicThermo>(basicThermo::dictName);
 
     fieldNames_.setSize(1);
     fieldNames_[0] = thermo.he().name();
@@ -86,8 +80,7 @@ void Foam::fv::radiation::addSup
     const label fieldi
 )
 {
-    const basicThermo& thermo =
-        mesh_.lookupObject<basicThermo>(basicThermo::dictName);
+    const auto& thermo = mesh_.lookupObject<basicThermo>(basicThermo::dictName);
 
     radiation_->correct();
 
diff --git a/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.H b/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.H
index 83eb7a95f2..723b53b2e4 100644
--- a/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.H
+++ b/src/thermophysicalModels/radiation/fvOptions/radiation/radiation.H
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2017 OpenFOAM Foundation
+    Copyright (C) 2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -27,17 +28,33 @@ Class
     Foam::fv::radiation
 
 Description
-    Calculates and applies the radiation source to the energy equation.
+    Applies radiation sources (i.e. \c Sh)
+    to the energy equation for compressible flows.
 
 Usage
-    Example usage:
+    Minimal example by using \c constant/fvOptions:
     \verbatim
-    radiationCoeffs
+    radiation1
     {
-        fields          (h);                    // Name of energy field
+        // Mandatory entries (unmodifiable)
+        type             radiation;
+        fields           (h);
+
+        // Mandatory/Optional (inherited) entries
+        ...
     }
     \endverbatim
 
+    where the entries mean:
+    \table
+      Property  | Description                       | Type   | Reqd  | Dflt
+      type      | Type name: radiation              | word   | yes   | -
+      fields    | Name of operand energy field      | word   | yes   | -
+    \endtable
+
+    The inherited entries are elaborated in:
+     - \link fvOption.H \endlink
+
 SourceFiles
     radiation.C
 
@@ -58,14 +75,14 @@ namespace fv
 {
 
 /*---------------------------------------------------------------------------*\
-               Class radiation Declaration
+                          Class radiation Declaration
 \*---------------------------------------------------------------------------*/
 
 class radiation
 :
     public option
 {
-    // Private data
+    // Private Data
 
         //- The radiation model pointer
         autoPtr<Foam::radiation::radiationModel> radiation_;