diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.C b/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.C
index ae637ef88f..e9ff0b4c4e 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.C
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.C
@@ -867,7 +867,14 @@ Foam::scalar Foam::chemistryModel<ThermoType>::solve
                 Rphiq[Rphiq.size()-2] = p;
                 Rphiq[Rphiq.size()-1] = deltaT[celli];
 
-                tabulation_.add(phiq, Rphiq, celli, rho0, deltaT[celli]);
+                tabulation_.add
+                (
+                    phiq,
+                    Rphiq,
+                    mechRed_.nActiveSpecies(),
+                    celli,
+                    deltaT[celli]
+                );
             }
 
             // When operations are done and if mechanism reduction is active,
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.H b/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.H
index 0c09e576cd..d18c1ef10c 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModel.H
@@ -330,9 +330,8 @@ public:
 
         // Mechanism reduction access functions
 
-            //- Return access to the mechanism reduction method
-            //  Needed by ISAT
-            inline const chemistryReductionMethod<ThermoType>& mechRed() const;
+            //- Return true if mechanism reduction is active
+            inline bool reduction() const;
 
             //- Allow the reduction method to reset the number of species
             inline void setNSpecie(const label newNs);
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModelI.H b/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModelI.H
index 61e5c58b93..2c1523c387 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModelI.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/chemistryModelI.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2016-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -119,10 +119,9 @@ Foam::chemistryModel<ThermoType>::Y() const
 
 
 template<class ThermoType>
-inline const Foam::chemistryReductionMethod<ThermoType>&
-Foam::chemistryModel<ThermoType>::mechRed() const
+inline bool Foam::chemistryModel<ThermoType>::reduction() const
 {
-    return mechRed_;
+    return mechRedActive_;
 }
 
 
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.C b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.C
index 460506337a..9a9e518d62 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.C
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.C
@@ -43,6 +43,7 @@ Foam::chemistryTabulationMethods::ISAT<ThermoType>::ISAT
     coeffsDict_(chemistryProperties.subDict("tabulation")),
     chemistry_(chemistry),
     log_(coeffsDict_.lookupOrDefault<Switch>("log", false)),
+    reduction_(chemistry_.reduction()),
     chemisTree_(*this, coeffsDict_),
     scaleFactor_(chemistry.nEqns() + 1, 1),
     runTime_(chemistry.time()),
@@ -198,7 +199,6 @@ void Foam::chemistryTabulationMethods::ISAT<ThermoType>::calcNewC
 )
 {
     const label nEqns = chemistry_.nEqns(); // Species, T, p
-    const bool mechRedActive = chemistry_.mechRed().active();
     const List<label>& completeToSimplified = phi0->completeToSimplifiedIndex();
 
     const scalarField dphi(phiq - phi0->phi());
@@ -213,12 +213,12 @@ void Foam::chemistryTabulationMethods::ISAT<ThermoType>::calcNewC
     Rphiq = phi0->Rphi();
     for (label i=0; i<nEqns + 1; i++)
     {
-        if (mechRedActive)
+        if (reduction_)
         {
             const label si =
                 i < nEqns - 2
               ? completeToSimplified[i]
-              : i - (nEqns - 2) + phi0->nActiveSpecies();
+              : i - (nEqns - 2) + phi0->nActive();
 
             if (si != -1)
             {
@@ -229,7 +229,7 @@ void Foam::chemistryTabulationMethods::ISAT<ThermoType>::calcNewC
                     const label sj =
                         j < nEqns - 2
                       ? completeToSimplified[j]
-                      : j - (nEqns - 2) + phi0->nActiveSpecies();
+                      : j - (nEqns - 2) + phi0->nActive();
 
                     if (sj != -1)
                     {
@@ -490,6 +490,7 @@ Foam::label Foam::chemistryTabulationMethods::ISAT<ThermoType>::add
 (
     const scalarField& phiq,
     const scalarField& Rphiq,
+    const label nActive,
     const label li,
     const scalar deltaT
 )
@@ -568,6 +569,7 @@ Foam::label Foam::chemistryTabulationMethods::ISAT<ThermoType>::add
                      scaleFactor(),
                      tolerance_,
                      scaleFactor_.size(),
+                     nActive,
                      nulPhi
                 );
                 deleteDemandDrivenData(tempList[i]);
@@ -592,6 +594,7 @@ Foam::label Foam::chemistryTabulationMethods::ISAT<ThermoType>::add
         scaleFactor(),
         tolerance_,
         scaleFactor_.size(),
+        nActive,
         lastSearch_ // lastSearch_ may be nullptr (handled by binaryTree)
     );
     if (lastSearch_ != nullptr)
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.H b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.H
index 61b048bad6..614521a2fd 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/ISAT.H
@@ -68,6 +68,9 @@ class ISAT
         //- Switch to select performance logging
         Switch log_;
 
+        //- Is reduction applied to the state vectors
+        const bool reduction_;
+
         //- List of the stored 'points' organised in a binary tree
         binaryTree<ThermoType> chemisTree_;
 
@@ -232,6 +235,12 @@ public:
             return true;
         }
 
+        //- Return true if reduction is applied to the state variables
+        bool reduction() const
+        {
+            return reduction_;
+        }
+
         const chemistryModel<ThermoType>& chemistry()
         {
             return chemistry_;
@@ -271,6 +280,7 @@ public:
         (
             const scalarField& phiq,
             const scalarField& Rphiq,
+            const label nActive,
             const label li,
             const scalar deltaT
         );
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryNode/binaryNode.C b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryNode/binaryNode.C
index e7fcb3fa6f..05ee98d6ee 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryNode/binaryNode.C
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryNode/binaryNode.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2016-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -70,7 +70,7 @@ void Foam::binaryNode<ThermoType>::calcV
 {
     // LT is the transpose of the L matrix
     scalarSquareMatrix& LT = elementLeft->LT();
-    bool mechReductionActive = elementLeft->chemistry().mechRed().active();
+    const bool reduction = elementLeft->table().reduction();
 
     // Difference of composition in the full species domain
     scalarField phiDif(elementRight->phi() - elementLeft->phi());
@@ -82,7 +82,7 @@ void Foam::binaryNode<ThermoType>::calcV
     {
         label si = i;
         bool outOfIndexI = true;
-        if (mechReductionActive)
+        if (reduction)
         {
             if (i<elementLeft->completeSpaceSize() - 3)
             {
@@ -93,17 +93,18 @@ void Foam::binaryNode<ThermoType>::calcV
             {
                 outOfIndexI = false;
                 const label dif = i - (elementLeft->completeSpaceSize() - 3);
-                si = elementLeft->nActiveSpecies() + dif;
+                si = elementLeft->nActive() + dif;
             }
         }
-        if (!mechReductionActive || (mechReductionActive && !(outOfIndexI)))
+        if (!reduction || (reduction && !(outOfIndexI)))
         {
             v[i] = 0;
             for (label j=0; j<elementLeft->completeSpaceSize(); j++)
             {
                 label sj = j;
                 bool outOfIndexJ = true;
-                if (mechReductionActive)
+
+                if (reduction)
                 {
                     if (j < elementLeft->completeSpaceSize() - 3)
                     {
@@ -115,14 +116,11 @@ void Foam::binaryNode<ThermoType>::calcV
                         outOfIndexJ = false;
                         const label dif =
                             j - (elementLeft->completeSpaceSize() - 3);
-                        sj = elementLeft->nActiveSpecies() + dif;
+                        sj = elementLeft->nActive() + dif;
                     }
                 }
-                if
-                (
-                    !mechReductionActive
-                  ||(mechReductionActive && !(outOfIndexJ))
-                )
+
+                if (!reduction ||(reduction && !(outOfIndexJ)))
                 {
                     // Since L is a lower triangular matrix k=0->min(i, j)
                     for (label k=0; k<=min(si, sj); k++)
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.C b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.C
index 9630cf4b73..0a137dfd50 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.C
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2016-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -382,6 +382,7 @@ void Foam::binaryTree<ThermoType>::insertNewLeaf
     const scalarField& scaleFactor,
     const scalar& epsTol,
     const label nCols,
+    const label nActive,
     chP*& phi0
 )
 {
@@ -401,6 +402,7 @@ void Foam::binaryTree<ThermoType>::insertNewLeaf
                 scaleFactor,
                 epsTol,
                 nCols,
+                nActive,
                 coeffsDict_,
                 root_
             );
@@ -428,6 +430,7 @@ void Foam::binaryTree<ThermoType>::insertNewLeaf
                 scaleFactor,
                 epsTol,
                 nCols,
+                nActive,
                 coeffsDict_
             );
         // insert new node on the parent node in the position of the
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.H b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.H
index d75ec0bcf3..644e079228 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/binaryTree/binaryTree.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2016-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -188,6 +188,7 @@ public:
             const scalarField& scaleFactor,
             const scalar& epsTol,
             const label nCols,
+            const label nActive,
             chP*& phi0
         );
 
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.C b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.C
index 33674c6204..e79148cea9 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.C
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2016-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -204,8 +204,9 @@ Foam::chemPointISAT<ThermoType>::chemPointISAT
     const scalarField& Rphi,
     const scalarSquareMatrix& A,
     const scalarField& scaleFactor,
-    const scalar& tolerance,
-    const label& completeSpaceSize,
+    const scalar tolerance,
+    const label completeSpaceSize,
+    const label nActive,
     const dictionary& coeffsDict,
     binaryNode<ThermoType>* node
 )
@@ -218,8 +219,8 @@ Foam::chemPointISAT<ThermoType>::chemPointISAT
     node_(node),
     completeSpaceSize_(completeSpaceSize),
     nGrowth_(0),
-    nActiveSpecies_(table_.chemistry().mechRed().nActiveSpecies()),
-    simplifiedToCompleteIndex_(nActiveSpecies_),
+    nActive_(nActive),
+    simplifiedToCompleteIndex_(nActive_),
     timeTag_(table.timeSteps()),
     lastTimeUsed_(table.timeSteps()),
     toRemove_(false),
@@ -237,21 +238,20 @@ Foam::chemPointISAT<ThermoType>::chemPointISAT
     idT_ = completeSpaceSize - 3;
     idp_ = completeSpaceSize - 2;
 
-    const bool mechRedActive = table_.chemistry().mechRed().active();
-    if (mechRedActive)
+    if (table_.reduction())
     {
         for (label i=0; i<completeSpaceSize-3; i++)
         {
             completeToSimplifiedIndex_[i] = table_.chemistry().cTos(i);
         }
-        for (label i=0; i<nActiveSpecies_; i++)
+        for (label i=0; i<nActive_; i++)
         {
             simplifiedToCompleteIndex_[i] = table_.chemistry().sToc(i);
         }
     }
 
     const label reduOrCompDim =
-        mechRedActive ? nActiveSpecies_ + 3 : completeSpaceSize;
+        table_.reduction() ? nActive_ + 3 : completeSpaceSize;
 
     // SVD decomposition A = U*D*V^T
     SVD svdA(A);
@@ -277,7 +277,7 @@ Foam::chemPointISAT<ThermoType>::chemPointISAT
         {
             label compi = i;
 
-            if (mechRedActive)
+            if (table_.reduction())
             {
                 compi = simplifiedToCompleteIndex(i);
             }
@@ -314,7 +314,7 @@ Foam::chemPointISAT<ThermoType>::chemPointISAT
     node_(p.node()),
     completeSpaceSize_(p.completeSpaceSize()),
     nGrowth_(p.nGrowth()),
-    nActiveSpecies_(p.nActiveSpecies()),
+    nActive_(p.nActive()),
     simplifiedToCompleteIndex_(p.simplifiedToCompleteIndex()),
     timeTag_(p.timeTag()),
     lastTimeUsed_(p.lastTimeUsed()),
@@ -338,10 +338,9 @@ template<class ThermoType>
 bool Foam::chemPointISAT<ThermoType>::inEOA(const scalarField& phiq)
 {
     const scalarField dphi(phiq - phi());
-    const bool mechRedActive = table_.chemistry().mechRed().active();
 
     const label dim =
-        mechRedActive ? nActiveSpecies_ : completeSpaceSize() - 3;
+        table_.reduction() ? nActive_ : completeSpaceSize() - 3;
 
     scalar epsTemp = 0;
     List<scalar> propEps(completeSpaceSize(), scalar(0));
@@ -355,19 +354,19 @@ bool Foam::chemPointISAT<ThermoType>::inEOA(const scalarField& phiq)
         // inactive species), just multiply the diagonal element and dphi
         if
         (
-            !(mechRedActive)
-          ||(mechRedActive && completeToSimplifiedIndex_[i] != -1)
+            !(table_.reduction())
+          ||(table_.reduction() && completeToSimplifiedIndex_[i] != -1)
         )
         {
             const label si =
-                mechRedActive
+                table_.reduction()
               ? completeToSimplifiedIndex_[i]
               : i;
 
             for (label j=si; j<dim; j++)// LT is upper triangular
             {
                 const label sj =
-                    mechRedActive
+                    table_.reduction()
                   ? simplifiedToCompleteIndex_[j]
                   : j;
 
@@ -487,18 +486,17 @@ bool Foam::chemPointISAT<ThermoType>::checkSolution
     const scalarField dphi(phiq - phi());
     const scalarField& scaleFactorV(scaleFactor());
     const scalarSquareMatrix& Avar(A());
-    const bool mechRedActive = table_.chemistry().mechRed().active();
     scalar dRl = 0;
 
     const label dim =
-        mechRedActive ? nActiveSpecies_ : completeSpaceSize() - 2;
+        table_.reduction() ? nActive_ : completeSpaceSize() - 2;
 
     // Since we build only the solution for the species, T and p are not
     // included
     for (label i=0; i<completeSpaceSize()-3; i++)
     {
         dRl = 0;
-        if (mechRedActive)
+        if (table_.reduction())
         {
             const label si = completeToSimplifiedIndex_[i];
 
@@ -510,9 +508,9 @@ bool Foam::chemPointISAT<ThermoType>::checkSolution
                     const label sj = simplifiedToCompleteIndex_[j];
                     dRl += Avar(si, j)*dphi[sj];
                 }
-                dRl += Avar(si, nActiveSpecies_)*dphi[idT_];
-                dRl += Avar(si, nActiveSpecies_+1)*dphi[idp_];
-                dRl += Avar(si, nActiveSpecies_+2)*dphi[iddeltaT_];
+                dRl += Avar(si, nActive_)*dphi[idT_];
+                dRl += Avar(si, nActive_+1)*dphi[idp_];
+                dRl += Avar(si, nActive_+2)*dphi[iddeltaT_];
             }
             else
             {
@@ -546,10 +544,9 @@ template<class ThermoType>
 bool Foam::chemPointISAT<ThermoType>::grow(const scalarField& phiq)
 {
     const scalarField dphi(phiq - phi());
-    const label initNActiveSpecies(nActiveSpecies_);
-    const bool mechRedActive = table_.chemistry().mechRed().active();
+    const label initNActiveSpecies(nActive_);
 
-    if (mechRedActive)
+    if (table_.reduction())
     {
         label activeAdded(0);
         DynamicList<label> dimToAdd(0);
@@ -602,11 +599,11 @@ bool Foam::chemPointISAT<ThermoType>::grow(const scalarField& phiq)
         }
 
         // the number of added dimension to the current chemPoint
-        nActiveSpecies_ += dimToAdd.size();
-        simplifiedToCompleteIndex_.setSize(nActiveSpecies_);
+        nActive_ += dimToAdd.size();
+        simplifiedToCompleteIndex_.setSize(nActive_);
         forAll(dimToAdd, i)
         {
-            label si = nActiveSpecies_ - dimToAdd.size() + i;
+            label si = nActive_ - dimToAdd.size() + i;
             // add the new active species
             simplifiedToCompleteIndex_[si] = dimToAdd[i];
             completeToSimplifiedIndex_[dimToAdd[i]] = si;
@@ -618,12 +615,12 @@ bool Foam::chemPointISAT<ThermoType>::grow(const scalarField& phiq)
         //  (change the diagonal position)
         //-set all element of the new lines and columns to zero except diagonal
         //  (=1/(tolerance*scaleFactor))
-        if (nActiveSpecies_ > initNActiveSpecies)
+        if (nActive_ > initNActiveSpecies)
         {
             const scalarSquareMatrix LTvar = LT_; // take a copy of LT_
             const scalarSquareMatrix Avar = A_; // take a copy of A_
-            LT_ = scalarSquareMatrix(nActiveSpecies_+3, Zero);
-            A_ = scalarSquareMatrix(nActiveSpecies_+3, Zero);
+            LT_ = scalarSquareMatrix(nActive_+3, Zero);
+            A_ = scalarSquareMatrix(nActive_+3, Zero);
 
             // write the initial active species
             for (label i=0; i<initNActiveSpecies; i++)
@@ -640,27 +637,27 @@ bool Foam::chemPointISAT<ThermoType>::grow(const scalarField& phiq)
             {
                 for (label j=1; j>=0; j--)
                 {
-                    LT_(i, nActiveSpecies_+j)=LTvar(i, initNActiveSpecies+j);
-                    A_(i, nActiveSpecies_+j)=Avar(i, initNActiveSpecies+j);
-                    LT_(nActiveSpecies_+j, i)=LTvar(initNActiveSpecies+j, i);
-                    A_(nActiveSpecies_+j, i)=Avar(initNActiveSpecies+j, i);
+                    LT_(i, nActive_+j)=LTvar(i, initNActiveSpecies+j);
+                    A_(i, nActive_+j)=Avar(i, initNActiveSpecies+j);
+                    LT_(nActive_+j, i)=LTvar(initNActiveSpecies+j, i);
+                    A_(nActive_+j, i)=Avar(initNActiveSpecies+j, i);
                 }
             }
             // end with the diagonal elements for temperature and pressure
-            LT_(nActiveSpecies_, nActiveSpecies_)=
+            LT_(nActive_, nActive_)=
                 LTvar(initNActiveSpecies, initNActiveSpecies);
-            A_(nActiveSpecies_, nActiveSpecies_)=
+            A_(nActive_, nActive_)=
                 Avar(initNActiveSpecies, initNActiveSpecies);
-            LT_(nActiveSpecies_+1, nActiveSpecies_+1)=
+            LT_(nActive_+1, nActive_+1)=
                 LTvar(initNActiveSpecies+1, initNActiveSpecies+1);
-            A_(nActiveSpecies_+1, nActiveSpecies_+1)=
+            A_(nActive_+1, nActive_+1)=
                 Avar(initNActiveSpecies+1, initNActiveSpecies+1);
-            LT_(nActiveSpecies_+2, nActiveSpecies_+2)=
+            LT_(nActive_+2, nActive_+2)=
                 LTvar(initNActiveSpecies+2, initNActiveSpecies+2);
-            A_(nActiveSpecies_+2, nActiveSpecies_+2)=
+            A_(nActive_+2, nActive_+2)=
                 Avar(initNActiveSpecies+2, initNActiveSpecies+2);
 
-            for (label i=initNActiveSpecies; i<nActiveSpecies_;i++)
+            for (label i=initNActiveSpecies; i<nActive_;i++)
             {
                 LT_(i, i)=
                     1.0
@@ -671,7 +668,7 @@ bool Foam::chemPointISAT<ThermoType>::grow(const scalarField& phiq)
     }
 
     const label dim =
-        mechRedActive ? nActiveSpecies_ + 3 : completeSpaceSize();
+        table_.reduction() ? nActive_ + 3 : completeSpaceSize();
 
     // beginning of grow algorithm
     scalarField phiTilde(dim, 0);
@@ -683,7 +680,7 @@ bool Foam::chemPointISAT<ThermoType>::grow(const scalarField& phiq)
         for (label j=i; j<dim-3; j++)// LT is upper triangular
         {
             const label sj =
-                mechRedActive
+                table_.reduction()
               ? simplifiedToCompleteIndex_[j]
               : j;
 
@@ -747,19 +744,19 @@ Foam::label Foam::chemPointISAT<ThermoType>::simplifiedToCompleteIndex
     const label i
 )
 {
-    if (i < nActiveSpecies_)
+    if (i < nActive_)
     {
         return simplifiedToCompleteIndex_[i];
     }
-    else if (i == nActiveSpecies_)
+    else if (i == nActive_)
     {
         return completeSpaceSize_ - 3;
     }
-    else if (i == nActiveSpecies_ + 1)
+    else if (i == nActive_ + 1)
     {
         return completeSpaceSize_ - 2;
     }
-    else if (i == nActiveSpecies_ + 2)
+    else if (i == nActive_ + 2)
     {
         return completeSpaceSize_ - 1;
     }
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.H b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.H
index ab982e6753..d91fa14ad6 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/ISAT/chemPointISAT/chemPointISAT.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2016-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -184,7 +184,7 @@ class chemPointISAT
         static scalar tolerance_;
 
         //- Number of active species stored in the chemPoint
-        label nActiveSpecies_;
+        label nActive_;
 
         //- Vectors that store the index conversion between the simplified
         //  and the complete chemical mechanism
@@ -256,8 +256,9 @@ public:
             const scalarField& Rphi,
             const scalarSquareMatrix& A,
             const scalarField& scaleFactor,
-            const scalar& tolerance,
-            const label& completeSpaceSize,
+            const scalar tolerance,
+            const label completeSpaceSize,
+            const label nActive,
             const dictionary& coeffsDict,
             binaryNode<ThermoType>* node = nullptr
         );
@@ -275,13 +276,13 @@ public:
 
     // Member Functions
 
-        //- Access to the chemistryModel
-        inline const chemistryModel<ThermoType>& chemistry()
+        //- Access to the ISAT table
+        inline const chemistryTabulationMethods::ISAT<ThermoType>& table() const
         {
-            return table_.chemistry();
+            return table_;
         }
 
-        inline label nGrowth()
+        inline label nGrowth() const
         {
             return nGrowth_;
         }
@@ -301,12 +302,12 @@ public:
             return Rphi_;
         }
 
-        inline const scalarField& scaleFactor()
+        inline const scalarField& scaleFactor() const
         {
             return scaleFactor_;
         }
 
-        inline const scalar& tolerance()
+        inline const scalar& tolerance() const
         {
             return tolerance_;
         }
@@ -341,9 +342,9 @@ public:
             return LT_;
         }
 
-        inline label nActiveSpecies()
+        inline label nActive()
         {
-            return nActiveSpecies_;
+            return nActive_;
         }
 
         inline List<label>& completeToSimplifiedIndex()
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/chemistryTabulationMethod/chemistryTabulationMethod.H b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/chemistryTabulationMethod/chemistryTabulationMethod.H
index a942fedf1d..c8ac056329 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/chemistryTabulationMethod/chemistryTabulationMethod.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/chemistryTabulationMethod/chemistryTabulationMethod.H
@@ -56,7 +56,6 @@ class chemistryModel;
 template<class ThermoType>
 class chemistryTabulationMethod
 {
-
 public:
 
     //- Runtime type information
@@ -123,6 +122,7 @@ public:
         (
             const scalarField& phiQ,
             const scalarField& RphiQ,
+            const label nActive,
             const label li,
             const scalar deltaT
         ) = 0;
diff --git a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/noChemistryTabulation/noChemistryTabulation.H b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/noChemistryTabulation/noChemistryTabulation.H
index 93cb9737d8..efdfdf19d1 100644
--- a/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/noChemistryTabulation/noChemistryTabulation.H
+++ b/src/thermophysicalModels/chemistryModel/chemistryModel/tabulation/noChemistryTabulation/noChemistryTabulation.H
@@ -103,6 +103,7 @@ public:
         (
             const scalarField& phiq,
             const scalarField& Rphiq,
+            const label nActive,
             const label li,
             const scalar deltaT
         )