diff --git a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C
index 652c9070f6..02cbae1f5c 100644
--- a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C
@@ -34,6 +34,76 @@ License
 #include "PatchInteractionModel.H"
 #include "PostProcessingModel.H"
 
+// * * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * //
+
+template<class ParcelType>
+void Foam::KinematicCloud<ParcelType>::preEvolve()
+{
+    this->dispersion().cacheFields(true);
+    forces_.cacheFields(true);
+}
+
+
+template<class ParcelType>
+void Foam::KinematicCloud<ParcelType>::evolveCloud()
+{
+    autoPtr<interpolation<scalar> > rhoInterpolator =
+        interpolation<scalar>::New
+        (
+            interpolationSchemes_,
+            rho_
+        );
+
+    autoPtr<interpolation<vector> > UInterpolator =
+        interpolation<vector>::New
+        (
+            interpolationSchemes_,
+            U_
+        );
+
+    autoPtr<interpolation<scalar> > muInterpolator =
+        interpolation<scalar>::New
+        (
+            interpolationSchemes_,
+            mu_
+        );
+
+    typename ParcelType::trackData td
+    (
+        *this,
+        constProps_,
+        rhoInterpolator(),
+        UInterpolator(),
+        muInterpolator(),
+        g_.value()
+    );
+
+    this->injection().inject(td);
+
+    if (coupled_)
+    {
+        resetSourceTerms();
+    }
+
+    Cloud<ParcelType>::move(td);
+}
+
+
+template<class ParcelType>
+void Foam::KinematicCloud<ParcelType>::postEvolve()
+{
+    if (debug)
+    {
+        this->writePositions();
+    }
+
+    this->dispersion().cacheFields(false);
+    forces_.cacheFields(false);
+
+    this->postProcessing().post();
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 template<class ParcelType>
@@ -62,6 +132,7 @@ Foam::KinematicCloud<ParcelType>::KinematicCloud
         )
     ),
     constProps_(particleProperties_),
+    active_(particleProperties_.lookup("active")),
     parcelTypeId_(readLabel(particleProperties_.lookup("parcelTypeId"))),
     coupled_(particleProperties_.lookup("coupled")),
     cellValueSourceCorrection_
@@ -179,75 +250,17 @@ void Foam::KinematicCloud<ParcelType>::resetSourceTerms()
 }
 
 
-template<class ParcelType>
-void Foam::KinematicCloud<ParcelType>::preEvolve()
-{
-    this->dispersion().cacheFields(true);
-    forces_.cacheFields(true);
-}
-
-
-template<class ParcelType>
-void Foam::KinematicCloud<ParcelType>::postEvolve()
-{
-    if (debug)
-    {
-        this->writePositions();
-    }
-
-    this->dispersion().cacheFields(false);
-    forces_.cacheFields(false);
-
-    this->postProcessing().post();
-}
-
-
 template<class ParcelType>
 void Foam::KinematicCloud<ParcelType>::evolve()
 {
-    preEvolve();
-
-    autoPtr<interpolation<scalar> > rhoInterpolator =
-        interpolation<scalar>::New
-        (
-            interpolationSchemes_,
-            rho_
-        );
-
-    autoPtr<interpolation<vector> > UInterpolator =
-        interpolation<vector>::New
-        (
-            interpolationSchemes_,
-            U_
-        );
-
-    autoPtr<interpolation<scalar> > muInterpolator =
-        interpolation<scalar>::New
-        (
-            interpolationSchemes_,
-            mu_
-        );
-
-    typename ParcelType::trackData td
-    (
-        *this,
-        constProps_,
-        rhoInterpolator(),
-        UInterpolator(),
-        muInterpolator(),
-        g_.value()
-    );
-
-    this->injection().inject(td);
-
-    if (coupled_)
+    if (active_)
     {
-        resetSourceTerms();
+        preEvolve();
+
+        evolveCloud();
+
+        postEvolve();
     }
-
-    Cloud<ParcelType>::move(td);
-
-    postEvolve();
 }
 
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H
index 4d5295b08d..3bd89a61a3 100644
--- a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H
@@ -109,6 +109,9 @@ protected:
         //- Parcel constant properties
         typename ParcelType::constantProperties constProps_;
 
+        //- Cloud active flag
+        const Switch active_;
+
         //- Parcel type id - used to flag the type of parcels issued by this
         //  cloud
         const label parcelTypeId_;
@@ -189,6 +192,9 @@ protected:
             //- Pre-evolve
             void preEvolve();
 
+            //- Evolve the cloud
+            void evolveCloud();
+
             //- Post-evolve
             void postEvolve();
 
@@ -223,9 +229,6 @@ public:
 
             // References to the mesh and databases
 
-                //- Return the parcel type id
-                inline label parcelTypeId() const;
-
                 //- Return refernce to the mesh
                 inline const fvMesh& mesh() const;
 
@@ -237,14 +240,22 @@ public:
                     constProps() const;
 
 
-            //- Return coupled flag
-            inline const Switch coupled() const;
+            // Cloud data
 
-            //- Return cell value correction flag
-            inline const Switch cellValueSourceCorrection() const;
+                //- Return the active flag
+                inline const Switch active() const;
 
-            //- Return refernce to the random object
-            inline Random& rndGen();
+                //- Return the parcel type id
+                inline label parcelTypeId() const;
+
+                //- Return coupled flag
+                inline const Switch coupled() const;
+
+                //- Return cell value correction flag
+                inline const Switch cellValueSourceCorrection() const;
+
+                //- Return refernce to the random object
+                inline Random& rndGen();
 
 
             // References to the carrier gas fields
diff --git a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H
index 1f48632d15..e65ed15741 100644
--- a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H
+++ b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H
@@ -58,6 +58,13 @@ Foam::KinematicCloud<ParcelType>::constProps() const
 }
 
 
+template<class ParcelType>
+inline const Foam::Switch Foam::KinematicCloud<ParcelType>::active() const
+{
+    return active_;
+}
+
+
 template<class ParcelType>
 inline const Foam::Switch Foam::KinematicCloud<ParcelType>::coupled() const
 {
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C
index 6f4b4bc763..210a589902 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C
@@ -58,6 +58,87 @@ void Foam::ReactingCloud<ParcelType>::checkSuppliedComposition
 }
 
 
+template<class ParcelType>
+void Foam::ReactingCloud<ParcelType>::preEvolve()
+{
+    ThermoCloud<ParcelType>::preEvolve();
+}
+
+
+template<class ParcelType>
+void Foam::ReactingCloud<ParcelType>::evolveCloud()
+{
+    const volScalarField& T = this->carrierThermo().T();
+    const volScalarField cp = this->carrierThermo().Cp();
+    const volScalarField& p = this->carrierThermo().p();
+
+    autoPtr<interpolation<scalar> > rhoInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        this->rho()
+    );
+
+    autoPtr<interpolation<vector> > UInterp = interpolation<vector>::New
+    (
+        this->interpolationSchemes(),
+        this->U()
+    );
+
+    autoPtr<interpolation<scalar> > muInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        this->mu()
+    );
+
+    autoPtr<interpolation<scalar> > TInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        T
+    );
+
+    autoPtr<interpolation<scalar> > cpInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        cp
+    );
+
+    autoPtr<interpolation<scalar> > pInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        p
+    );
+
+    typename ParcelType::trackData td
+    (
+        *this,
+        constProps_,
+        rhoInterp(),
+        UInterp(),
+        muInterp(),
+        TInterp(),
+        cpInterp(),
+        pInterp(),
+        this->g().value()
+    );
+
+    this->injection().inject(td);
+
+    if (this->coupled())
+    {
+        resetSourceTerms();
+    }
+
+    Cloud<ParcelType>::move(td);
+}
+
+
+template<class ParcelType>
+void Foam::ReactingCloud<ParcelType>::postEvolve()
+{
+    ThermoCloud<ParcelType>::postEvolve();
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 template<class ParcelType>
@@ -181,88 +262,17 @@ void Foam::ReactingCloud<ParcelType>::resetSourceTerms()
 }
 
 
-template<class ParcelType>
-void Foam::ReactingCloud<ParcelType>::preEvolve()
-{
-    ThermoCloud<ParcelType>::preEvolve();
-}
-
-
-template<class ParcelType>
-void Foam::ReactingCloud<ParcelType>::postEvolve()
-{
-    ThermoCloud<ParcelType>::postEvolve();
-}
-
-
 template<class ParcelType>
 void Foam::ReactingCloud<ParcelType>::evolve()
 {
-    preEvolve();
-
-    const volScalarField& T = this->carrierThermo().T();
-    const volScalarField cp = this->carrierThermo().Cp();
-    const volScalarField& p = this->carrierThermo().p();
-
-    autoPtr<interpolation<scalar> > rhoInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        this->rho()
-    );
-
-    autoPtr<interpolation<vector> > UInterp = interpolation<vector>::New
-    (
-        this->interpolationSchemes(),
-        this->U()
-    );
-
-    autoPtr<interpolation<scalar> > muInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        this->mu()
-    );
-
-    autoPtr<interpolation<scalar> > TInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        T
-    );
-
-    autoPtr<interpolation<scalar> > cpInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        cp
-    );
-
-    autoPtr<interpolation<scalar> > pInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        p
-    );
-
-    typename ParcelType::trackData td
-    (
-        *this,
-        constProps_,
-        rhoInterp(),
-        UInterp(),
-        muInterp(),
-        TInterp(),
-        cpInterp(),
-        pInterp(),
-        this->g().value()
-    );
-
-    this->injection().inject(td);
-
-    if (this->coupled())
+    if (this->active())
     {
-        resetSourceTerms();
+        preEvolve();
+
+        evolveCloud();
+
+        postEvolve();
     }
-
-    Cloud<ParcelType>::move(td);
-
-    postEvolve();
 }
 
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H
index 23f579649a..fe9ca29aee 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H
@@ -137,6 +137,9 @@ protected:
             //- Pre-evolve
             void preEvolve();
 
+            //- Evolve the cloud
+            void evolveCloud();
+
             //- Post-evolve
             void postEvolve();
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C
index e81aa2ee8d..b783cb2b08 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C
@@ -29,6 +29,89 @@ License
 #include "DevolatilisationModel.H"
 #include "SurfaceReactionModel.H"
 
+// * * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * //
+
+template<class ParcelType>
+void Foam::ReactingMultiphaseCloud<ParcelType>::preEvolve()
+{
+    ReactingCloud<ParcelType>::preEvolve();
+}
+
+
+template<class ParcelType>
+void Foam::ReactingMultiphaseCloud<ParcelType>::evolveCloud()
+{
+    const volScalarField& T = this->carrierThermo().T();
+    const volScalarField cp = this->carrierThermo().Cp();
+    const volScalarField& p = this->carrierThermo().p();
+
+    autoPtr<interpolation<scalar> > rhoInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        this->rho()
+    );
+
+    autoPtr<interpolation<vector> > UInterp = interpolation<vector>::New
+    (
+        this->interpolationSchemes(),
+        this->U()
+    );
+
+    autoPtr<interpolation<scalar> > muInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        this->mu()
+    );
+
+    autoPtr<interpolation<scalar> > TInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        T
+    );
+
+    autoPtr<interpolation<scalar> > cpInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        cp
+    );
+
+    autoPtr<interpolation<scalar> > pInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        p
+    );
+
+    typename ParcelType::trackData td
+    (
+        *this,
+        constProps_,
+        rhoInterp(),
+        UInterp(),
+        muInterp(),
+        TInterp(),
+        cpInterp(),
+        pInterp(),
+        this->g().value()
+    );
+
+    this->injection().inject(td);
+
+    if (this->coupled())
+    {
+        resetSourceTerms();
+    }
+
+    Cloud<ParcelType>::move(td);
+}
+
+
+template<class ParcelType>
+void Foam::ReactingMultiphaseCloud<ParcelType>::postEvolve()
+{
+    ReactingCloud<ParcelType>::postEvolve();
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 template<class ParcelType>
@@ -135,88 +218,17 @@ void Foam::ReactingMultiphaseCloud<ParcelType>::resetSourceTerms()
 }
 
 
-template<class ParcelType>
-void Foam::ReactingMultiphaseCloud<ParcelType>::preEvolve()
-{
-    ReactingCloud<ParcelType>::preEvolve();
-}
-
-
-template<class ParcelType>
-void Foam::ReactingMultiphaseCloud<ParcelType>::postEvolve()
-{
-    ReactingCloud<ParcelType>::postEvolve();
-}
-
-
 template<class ParcelType>
 void Foam::ReactingMultiphaseCloud<ParcelType>::evolve()
 {
-    preEvolve();
-
-    const volScalarField& T = this->carrierThermo().T();
-    const volScalarField cp = this->carrierThermo().Cp();
-    const volScalarField& p = this->carrierThermo().p();
-
-    autoPtr<interpolation<scalar> > rhoInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        this->rho()
-    );
-
-    autoPtr<interpolation<vector> > UInterp = interpolation<vector>::New
-    (
-        this->interpolationSchemes(),
-        this->U()
-    );
-
-    autoPtr<interpolation<scalar> > muInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        this->mu()
-    );
-
-    autoPtr<interpolation<scalar> > TInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        T
-    );
-
-    autoPtr<interpolation<scalar> > cpInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        cp
-    );
-
-    autoPtr<interpolation<scalar> > pInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        p
-    );
-
-    typename ParcelType::trackData td
-    (
-        *this,
-        constProps_,
-        rhoInterp(),
-        UInterp(),
-        muInterp(),
-        TInterp(),
-        cpInterp(),
-        pInterp(),
-        this->g().value()
-    );
-
-    this->injection().inject(td);
-
-    if (this->coupled())
+    if (this->active())
     {
-        resetSourceTerms();
+        preEvolve();
+
+        evolveCloud();
+
+        postEvolve();
     }
-
-    Cloud<ParcelType>::move(td);
-
-    postEvolve();
 }
 
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
index 61dcdf6679..d3cf593678 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
@@ -119,6 +119,9 @@ protected:
             //- Pre-evolve
             void preEvolve();
 
+            //- Evolve the cloud
+            void evolveCloud();
+
             //- Post-evolve
             void postEvolve();
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C
index 28fa0b20e7..0d12d286b9 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C
@@ -30,6 +30,81 @@ License
 
 #include "HeatTransferModel.H"
 
+// * * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * //
+
+template<class ParcelType>
+void Foam::ThermoCloud<ParcelType>::preEvolve()
+{
+    KinematicCloud<ParcelType>::preEvolve();
+}
+
+
+template<class ParcelType>
+void Foam::ThermoCloud<ParcelType>::evolveCloud()
+{
+    const volScalarField& T = carrierThermo_.T();
+    const volScalarField cp = carrierThermo_.Cp();
+
+    autoPtr<interpolation<scalar> > rhoInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        this->rho()
+    );
+
+    autoPtr<interpolation<vector> > UInterp = interpolation<vector>::New
+    (
+        this->interpolationSchemes(),
+        this->U()
+    );
+
+    autoPtr<interpolation<scalar> > muInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        this->mu()
+    );
+
+    autoPtr<interpolation<scalar> > TInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        T
+    );
+
+    autoPtr<interpolation<scalar> > cpInterp = interpolation<scalar>::New
+    (
+        this->interpolationSchemes(),
+        cp
+    );
+
+    typename ParcelType::trackData td
+    (
+        *this,
+        constProps_,
+        rhoInterp(),
+        UInterp(),
+        muInterp(),
+        TInterp(),
+        cpInterp(),
+        this->g().value()
+    );
+
+    this->injection().inject(td);
+
+    if (this->coupled())
+    {
+        resetSourceTerms();
+    }
+
+    Cloud<ParcelType>::move(td);
+}
+
+
+template<class ParcelType>
+void Foam::ThermoCloud<ParcelType>::postEvolve()
+{
+    KinematicCloud<ParcelType>::postEvolve();
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 template<class ParcelType>
@@ -149,80 +224,17 @@ void Foam::ThermoCloud<ParcelType>::resetSourceTerms()
 }
 
 
-template<class ParcelType>
-void Foam::ThermoCloud<ParcelType>::preEvolve()
-{
-    KinematicCloud<ParcelType>::preEvolve();
-}
-
-
-template<class ParcelType>
-void Foam::ThermoCloud<ParcelType>::postEvolve()
-{
-    KinematicCloud<ParcelType>::postEvolve();
-}
-
-
 template<class ParcelType>
 void Foam::ThermoCloud<ParcelType>::evolve()
 {
-    preEvolve();
-
-    const volScalarField& T = carrierThermo_.T();
-    const volScalarField cp = carrierThermo_.Cp();
-
-    autoPtr<interpolation<scalar> > rhoInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        this->rho()
-    );
-
-    autoPtr<interpolation<vector> > UInterp = interpolation<vector>::New
-    (
-        this->interpolationSchemes(),
-        this->U()
-    );
-
-    autoPtr<interpolation<scalar> > muInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        this->mu()
-    );
-
-    autoPtr<interpolation<scalar> > TInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        T
-    );
-
-    autoPtr<interpolation<scalar> > cpInterp = interpolation<scalar>::New
-    (
-        this->interpolationSchemes(),
-        cp
-    );
-
-    typename ParcelType::trackData td
-    (
-        *this,
-        constProps_,
-        rhoInterp(),
-        UInterp(),
-        muInterp(),
-        TInterp(),
-        cpInterp(),
-        this->g().value()
-    );
-
-    this->injection().inject(td);
-
-    if (this->coupled())
+    if (this->active())
     {
-        resetSourceTerms();
+        preEvolve();
+
+        evolveCloud();
+
+        postEvolve();
     }
-
-    Cloud<ParcelType>::move(td);
-
-    postEvolve();
 }
 
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H
index 793a563f5b..c0e2d5864a 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H
@@ -125,6 +125,9 @@ protected:
             //- Pre-evolve
             void preEvolve();
 
+            //- Evolve the cloud
+            void evolveCloud();
+
             //- Post-evolve
             void postEvolve();