diff --git a/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.C b/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.C
index 013f4ad179..cfdc342b3a 100644
--- a/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.C
+++ b/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.C
@@ -31,11 +31,6 @@ License
 #include "OFstream.H"
 #include "ListOps.H"
 
-// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
-
-template<class Type>
-Foam::scalar Foam::dynamicIndexedOctree<Type>::perturbTol_ = 10*SMALL;
-
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 template<class Type>
@@ -2046,13 +2041,6 @@ Foam::dynamicIndexedOctree<Type>::dynamicIndexedOctree
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-template<class Type>
-Foam::scalar& Foam::dynamicIndexedOctree<Type>::perturbTol()
-{
-    return perturbTol_;
-}
-
-
 template<class Type>
 Foam::pointIndexHit Foam::dynamicIndexedOctree<Type>::findNearest
 (
diff --git a/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.H b/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.H
index 8512c1882b..3c71965879 100644
--- a/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.H
+++ b/src/OpenFOAM/algorithms/dynamicIndexedOctree/dynamicIndexedOctree.H
@@ -89,15 +89,6 @@ class dynamicIndexedOctree
 :
     public dynamicIndexedOctreeBase
 {
-    // Static data
-
-        //- Relative perturbation tolerance. Determines when point is
-        //  considered to be close to face/edge of bb of node.
-        //  The tolerance is relative to the bounding box of the smallest
-        //  node.
-        static scalar perturbTol_;
-
-
     // Private Data
 
         //- Underlying shapes for geometric queries.
@@ -333,10 +324,6 @@ class dynamicIndexedOctree
 
 public:
 
-        //- Get the perturbation tolerance
-        static scalar& perturbTol();
-
-
     // Constructors
 
         //- Construct from shapes
diff --git a/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.C b/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.C
index 4a71b43fa7..6d09bdc263 100644
--- a/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.C
+++ b/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.C
@@ -32,12 +32,6 @@ License
 #include "ListOps.H"
 #include "memInfo.H"
 
-// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
-
-template<class Type>
-Foam::scalar Foam::indexedOctree<Type>::perturbTol_ = 10*SMALL;
-
-
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 template<class Type>
@@ -2293,13 +2287,6 @@ Foam::indexedOctree<Type>::indexedOctree
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-template<class Type>
-Foam::scalar& Foam::indexedOctree<Type>::perturbTol()
-{
-    return perturbTol_;
-}
-
-
 template<class Type>
 Foam::pointIndexHit Foam::indexedOctree<Type>::findNearest
 (
diff --git a/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.H b/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.H
index 9f39421b3d..6d9bee036b 100644
--- a/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.H
+++ b/src/OpenFOAM/algorithms/indexedOctree/indexedOctree.H
@@ -178,6 +178,16 @@ public:
 
 protected:
 
+    // Static Data
+
+        //- Relative perturbation tolerance.
+        //  Determines when point is considered to be close to face/edge
+        //  of bb of node.
+        //  The tolerance is relative to the bounding box of the smallest
+        //  node.
+        static scalar perturbTol_;
+
+
     // Protected Member Functions
 
     // Encode node addressing
@@ -204,6 +214,18 @@ protected:
 
 public:
 
+    //- Get the perturbation tolerance
+    static scalar& perturbTol() noexcept { return perturbTol_; }
+
+    //- Set the perturbation tolerance, return the old value
+    static scalar perturbTol(scalar tol) noexcept
+    {
+        scalar old(perturbTol_);
+        perturbTol_ = tol;
+        return old;
+    }
+
+
     //- Runtime type information
     ClassName("indexedOctree");
 
@@ -236,15 +258,6 @@ class indexedOctree
 :
     public indexedOctreeBase
 {
-    // Static data
-
-        //- Relative perturbation tolerance. Determines when point is
-        //  considered to be close to face/edge of bb of node.
-        //  The tolerance is relative to the bounding box of the smallest
-        //  node.
-        static scalar perturbTol_;
-
-
     // Private Data
 
         //- Underlying shapes for geometric queries.
@@ -489,10 +502,6 @@ class indexedOctree
 
 public:
 
-        //- Get the perturbation tolerance
-        static scalar& perturbTol();
-
-
     // Constructors
 
         //- Construct null
diff --git a/src/OpenFOAM/algorithms/indexedOctree/indexedOctreeBase.C b/src/OpenFOAM/algorithms/indexedOctree/indexedOctreeBase.C
index 416c39a8c7..854859fdb7 100644
--- a/src/OpenFOAM/algorithms/indexedOctree/indexedOctreeBase.C
+++ b/src/OpenFOAM/algorithms/indexedOctree/indexedOctreeBase.C
@@ -34,6 +34,8 @@ License
 namespace Foam
 {
     defineTypeNameAndDebug(indexedOctreeBase, 0);
+
+    scalar indexedOctreeBase::perturbTol_ = 10*SMALL;
 }
 
 
diff --git a/src/meshTools/searchableSurfaces/triSurfaceMesh/triSurfaceMesh.C b/src/meshTools/searchableSurfaces/triSurfaceMesh/triSurfaceMesh.C
index 4714300105..8a87d50dba 100644
--- a/src/meshTools/searchableSurfaces/triSurfaceMesh/triSurfaceMesh.C
+++ b/src/meshTools/searchableSurfaces/triSurfaceMesh/triSurfaceMesh.C
@@ -801,8 +801,8 @@ Foam::triSurfaceMesh::edgeTree() const
                 << "calculating edge tree for bb:" << bb << endl;
         }
 
-        scalar oldTol = indexedOctree<treeDataEdge>::perturbTol();
-        indexedOctree<treeDataEdge>::perturbTol() = tolerance();
+        const scalar oldTol =
+            indexedOctree<treeDataEdge>::perturbTol(tolerance());
 
         edgeTree_.reset
         (
@@ -822,7 +822,7 @@ Foam::triSurfaceMesh::edgeTree() const
             )
         );
 
-        indexedOctree<treeDataEdge>::perturbTol() = oldTol;
+        indexedOctree<treeDataEdge>::perturbTol(oldTol);
 
         if (debug)
         {
@@ -1221,8 +1221,8 @@ void Foam::triSurfaceMesh::getVolumeType
     List<volumeType>& volType
 ) const
 {
-    const scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
-    indexedOctree<treeDataTriSurface>::perturbTol() = tolerance();
+    const scalar oldTol =
+        indexedOctree<treeDataTriSurface>::perturbTol(tolerance());
 
     if (debug)
     {
@@ -1258,7 +1258,8 @@ void Foam::triSurfaceMesh::getVolumeType
         }
     }
 
-    indexedOctree<treeDataTriSurface>::perturbTol() = oldTol;
+    indexedOctree<treeDataTriSurface>::perturbTol(oldTol);
+
     if (debug)
     {
         Pout<< "triSurfaceMesh::getVolumeType :"
diff --git a/src/meshTools/triSurface/triSurfaceSearch/triSurfaceRegionSearch.C b/src/meshTools/triSurface/triSurfaceSearch/triSurfaceRegionSearch.C
index 54e5c35245..d58ec499bf 100644
--- a/src/meshTools/triSurface/triSurfaceSearch/triSurfaceRegionSearch.C
+++ b/src/meshTools/triSurface/triSurfaceSearch/triSurfaceRegionSearch.C
@@ -108,8 +108,7 @@ Foam::triSurfaceRegionSearch::treeByRegion() const
 
         forAll(regionsAddressing, regionI)
         {
-            scalar oldTol = treeType::perturbTol();
-            treeType::perturbTol() = tolerance();
+            const scalar oldTol = treeType::perturbTol(tolerance());
 
             indirectRegionPatches_.set
             (
@@ -177,7 +176,7 @@ Foam::triSurfaceRegionSearch::treeByRegion() const
                 )
             );
 
-            treeType::perturbTol() = oldTol;
+            treeType::perturbTol(oldTol);
         }
     }
 
@@ -199,8 +198,7 @@ void Foam::triSurfaceRegionSearch::findNearest
     }
     else
     {
-        scalar oldTol = treeType::perturbTol();
-        treeType::perturbTol() = tolerance();
+        const scalar oldTol = treeType::perturbTol(tolerance());
 
         const PtrList<treeType>& octrees = treeByRegion();
 
@@ -249,7 +247,7 @@ void Foam::triSurfaceRegionSearch::findNearest
             }
         }
 
-        treeType::perturbTol() = oldTol;
+        treeType::perturbTol(oldTol);
     }
 }
 
diff --git a/src/meshTools/triSurface/triSurfaceSearch/triSurfaceSearch.C b/src/meshTools/triSurface/triSurfaceSearch/triSurfaceSearch.C
index 63853a2d3b..156b545dea 100644
--- a/src/meshTools/triSurface/triSurfaceSearch/triSurfaceSearch.C
+++ b/src/meshTools/triSurface/triSurfaceSearch/triSurfaceSearch.C
@@ -233,8 +233,8 @@ Foam::triSurfaceSearch::tree() const
             bb.inflate(rndGen, 1e-4, ROOTVSMALL);
         }
 
-        const scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
-        indexedOctree<treeDataTriSurface>::perturbTol() = tolerance_;
+        const scalar oldTol =
+            indexedOctree<treeDataTriSurface>::perturbTol(tolerance_);
 
         treePtr_.reset
         (
@@ -248,7 +248,7 @@ Foam::triSurfaceSearch::tree() const
             )
         );
 
-        indexedOctree<treeDataTriSurface>::perturbTol() = oldTol;
+        indexedOctree<treeDataTriSurface>::perturbTol(oldTol);
     }
 
     return *treePtr_;
@@ -291,8 +291,8 @@ void Foam::triSurfaceSearch::findNearest
     List<pointIndexHit>& info
 ) const
 {
-    const scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
-    indexedOctree<treeDataTriSurface>::perturbTol() = tolerance();
+    const scalar oldTol =
+        indexedOctree<treeDataTriSurface>::perturbTol(tolerance());
 
     const indexedOctree<treeDataTriSurface>& octree = tree();
 
@@ -310,7 +310,7 @@ void Foam::triSurfaceSearch::findNearest
         );
     }
 
-    indexedOctree<treeDataTriSurface>::perturbTol() = oldTol;
+    indexedOctree<treeDataTriSurface>::perturbTol(oldTol);
 }
 
 
@@ -338,15 +338,15 @@ void Foam::triSurfaceSearch::findLine
 
     info.setSize(start.size());
 
-    const scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
-    indexedOctree<treeDataTriSurface>::perturbTol() = tolerance();
+    const scalar oldTol =
+        indexedOctree<treeDataTriSurface>::perturbTol(tolerance());
 
     forAll(start, i)
     {
         info[i] = octree.findLine(start[i], end[i]);
     }
 
-    indexedOctree<treeDataTriSurface>::perturbTol() = oldTol;
+    indexedOctree<treeDataTriSurface>::perturbTol(oldTol);
 }
 
 
@@ -361,15 +361,15 @@ void Foam::triSurfaceSearch::findLineAny
 
     info.setSize(start.size());
 
-    const scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
-    indexedOctree<treeDataTriSurface>::perturbTol() = tolerance();
+    const scalar oldTol =
+        indexedOctree<treeDataTriSurface>::perturbTol(tolerance());
 
     forAll(start, i)
     {
         info[i] = octree.findLineAny(start[i], end[i]);
     }
 
-    indexedOctree<treeDataTriSurface>::perturbTol() = oldTol;
+    indexedOctree<treeDataTriSurface>::perturbTol(oldTol);
 }
 
 
@@ -384,8 +384,8 @@ void Foam::triSurfaceSearch::findLineAll
 
     info.setSize(start.size());
 
-    const scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
-    indexedOctree<treeDataTriSurface>::perturbTol() = tolerance();
+    const scalar oldTol =
+        indexedOctree<treeDataTriSurface>::perturbTol(tolerance());
 
     // Work array
     DynamicList<pointIndexHit> hits;
@@ -437,7 +437,7 @@ void Foam::triSurfaceSearch::findLineAll
         info[pointi].transfer(hits);
     }
 
-    indexedOctree<treeDataTriSurface>::perturbTol() = oldTol;
+    indexedOctree<treeDataTriSurface>::perturbTol(oldTol);
 }