diff --git a/src/BRepExtrema/BRepExtrema_ExtCC.cxx b/src/BRepExtrema/BRepExtrema_ExtCC.cxx
index c4fbdc97eb..e66a067431 100644
--- a/src/BRepExtrema/BRepExtrema_ExtCC.cxx
+++ b/src/BRepExtrema/BRepExtrema_ExtCC.cxx
@@ -40,7 +40,9 @@ BRepExtrema_ExtCC::BRepExtrema_ExtCC(const TopoDS_Edge& E1, const TopoDS_Edge& E
 
 void BRepExtrema_ExtCC::Initialize(const TopoDS_Edge& E2)
 {
-  Standard_Real V1,V2;
+  if (!BRep_Tool::IsGeometric(E2))
+    return;  // protect against non-geometric type (e.g. polygon)
+  Standard_Real V1, V2;
   BRepAdaptor_Curve Curv(E2);
   myHC = new BRepAdaptor_HCurve(Curv);
   Standard_Real Tol = Min(BRep_Tool::Tolerance(E2), Precision::Confusion());
@@ -57,6 +59,8 @@ void BRepExtrema_ExtCC::Initialize(const TopoDS_Edge& E2)
 
 void BRepExtrema_ExtCC::Perform(const TopoDS_Edge& E1)
 {
+  if (!BRep_Tool::IsGeometric(E1))
+    return;  // protect against non-geometric type (e.g. polygon)
   Standard_Real U1, U2;
   BRepAdaptor_Curve Curv(E1);
   Handle(BRepAdaptor_HCurve) HC = new BRepAdaptor_HCurve(Curv);
diff --git a/src/BRepExtrema/BRepExtrema_ExtCF.cxx b/src/BRepExtrema/BRepExtrema_ExtCF.cxx
index 897f2018c1..59d67b3c44 100644
--- a/src/BRepExtrema/BRepExtrema_ExtCF.cxx
+++ b/src/BRepExtrema/BRepExtrema_ExtCF.cxx
@@ -45,6 +45,9 @@ BRepExtrema_ExtCF::BRepExtrema_ExtCF(const TopoDS_Edge& E, const TopoDS_Face& F)
 void BRepExtrema_ExtCF::Initialize(const TopoDS_Edge& E, const TopoDS_Face& F)
 {
   BRepAdaptor_Surface Surf(F);
+  if (Surf.GetType() == GeomAbs_OtherSurface ||
+      !BRep_Tool::IsGeometric(E))
+    return; // protect against non-geometric type (e.g. triangulation)
   BRepAdaptor_Curve aC(E);
   myHS = new BRepAdaptor_HSurface(Surf);
   Standard_Real aTolC, aTolS;
@@ -73,6 +76,9 @@ void BRepExtrema_ExtCF::Perform(const TopoDS_Edge& E, const TopoDS_Face& F2)
   myPointsOnS.Clear();
   myPointsOnC.Clear();
 
+  if (myHS.IsNull())
+    return; // protect against non-geometric type (e.g. triangulation)
+
   Standard_Real U1, U2;
   BRep_Tool::Range(E, U1, U2);
 
diff --git a/src/BRepExtrema/BRepExtrema_ExtFF.cxx b/src/BRepExtrema/BRepExtrema_ExtFF.cxx
index 0881dcc4cb..e777f25cc6 100644
--- a/src/BRepExtrema/BRepExtrema_ExtFF.cxx
+++ b/src/BRepExtrema/BRepExtrema_ExtFF.cxx
@@ -46,6 +46,9 @@ BRepExtrema_ExtFF::BRepExtrema_ExtFF(const TopoDS_Face& F1, const TopoDS_Face& F
 void BRepExtrema_ExtFF::Initialize(const TopoDS_Face& F2)
 {
   BRepAdaptor_Surface Surf(F2);
+  if (Surf.GetType() == GeomAbs_OtherSurface)
+    return; // protect against non-geometric type (e.g. triangulation)
+
   myHS = new BRepAdaptor_HSurface(Surf);
   Standard_Real Tol = Min(BRep_Tool::Tolerance(F2), Precision::Confusion());
   Tol = Min(Surf.UResolution(Tol), Surf.VResolution(Tol));
@@ -67,6 +70,9 @@ void BRepExtrema_ExtFF::Perform(const TopoDS_Face& F1, const TopoDS_Face& F2)
   myPointsOnS2.Clear();
 
   BRepAdaptor_Surface Surf1(F1);
+  if (myHS.IsNull() || Surf1.GetType() == GeomAbs_OtherSurface)
+    return; // protect against non-geometric type (e.g. triangulation)
+
   Handle(BRepAdaptor_HSurface) HS1 = new BRepAdaptor_HSurface(Surf1);
   Standard_Real Tol1 = Min(BRep_Tool::Tolerance(F1), Precision::Confusion());
   Tol1 = Min(Surf1.UResolution(Tol1), Surf1.VResolution(Tol1));
diff --git a/src/BRepExtrema/BRepExtrema_ExtPC.cxx b/src/BRepExtrema/BRepExtrema_ExtPC.cxx
index 4c491c8863..a74939ca8a 100644
--- a/src/BRepExtrema/BRepExtrema_ExtPC.cxx
+++ b/src/BRepExtrema/BRepExtrema_ExtPC.cxx
@@ -41,7 +41,9 @@ BRepExtrema_ExtPC::BRepExtrema_ExtPC(const TopoDS_Vertex& V, const TopoDS_Edge&
 
 void BRepExtrema_ExtPC::Initialize(const TopoDS_Edge& E)
 {
-  Standard_Real U1,U2;
+  if (!BRep_Tool::IsGeometric(E))
+    return;  // protect against non-geometric type (e.g. polygon)
+  Standard_Real U1, U2;
   BRepAdaptor_Curve Curv(E);
   myHC = new BRepAdaptor_HCurve(Curv);
   Standard_Real Tol = Min(BRep_Tool::Tolerance(E), Precision::Confusion());
@@ -57,6 +59,9 @@ void BRepExtrema_ExtPC::Initialize(const TopoDS_Edge& E)
 
 void BRepExtrema_ExtPC::Perform(const TopoDS_Vertex& V)
 {
-  gp_Pnt P = BRep_Tool::Pnt(V);
-  myExtPC.Perform(P);
+  if (!myHC.IsNull())
+  {
+    gp_Pnt P = BRep_Tool::Pnt(V);
+    myExtPC.Perform(P);
+  }
 }
diff --git a/src/BRepExtrema/BRepExtrema_ExtPF.cxx b/src/BRepExtrema/BRepExtrema_ExtPF.cxx
index 5b2d4be300..41493900b9 100644
--- a/src/BRepExtrema/BRepExtrema_ExtPF.cxx
+++ b/src/BRepExtrema/BRepExtrema_ExtPF.cxx
@@ -49,6 +49,10 @@ void BRepExtrema_ExtPF::Initialize(const TopoDS_Face& TheFace,
   // cette surface doit etre en champ. Extrema ne fait
   // pas de copie et prend seulement un pointeur dessus.
   mySurf.Initialize(TheFace, Standard_False); 
+
+  if (mySurf.GetType() == GeomAbs_OtherSurface)
+    return;  // protect against non-geometric type (e.g. triangulation)
+
   Standard_Real Tol = Min(BRep_Tool::Tolerance(TheFace), Precision::Confusion());
   Standard_Real aTolU, aTolV;
   aTolU = Max(mySurf.UResolution(Tol), Precision::PConfusion());
@@ -71,6 +75,9 @@ void BRepExtrema_ExtPF::Perform(const TopoDS_Vertex& TheVertex, const TopoDS_Fac
   myPoints.Clear();
 
   const gp_Pnt P = BRep_Tool::Pnt(TheVertex);
+  if (mySurf.GetType() == GeomAbs_OtherSurface)
+    return;  // protect against non-geometric type (e.g. triangulation)
+  
   myExtPS.Perform(P);
 
   // Exploration of points and classification
diff --git a/src/BRepGProp/BRepGProp.cxx b/src/BRepGProp/BRepGProp.cxx
index 14dca7b99b..4cc0f1da40 100644
--- a/src/BRepGProp/BRepGProp.cxx
+++ b/src/BRepGProp/BRepGProp.cxx
@@ -170,6 +170,7 @@ static Standard_Real volumeProperties(const TopoDS_Shape& S, GProp_GProps& Props
   BRepGProp_Domain BD;
   TopTools_MapOfShape aFwdFMap;
   TopTools_MapOfShape aRvsFMap;
+  TopLoc_Location aLocDummy;
 
   for (ex.Init(S,TopAbs_FACE), i = 1; ex.More(); ex.Next(), i++) {
     const TopoDS_Face& F = TopoDS::Face(ex.Current());
@@ -187,6 +188,15 @@ static Standard_Real volumeProperties(const TopoDS_Shape& S, GProp_GProps& Props
         continue;
       }
     }
+    {
+      const Handle(Geom_Surface)& aSurf = BRep_Tool::Surface (F, aLocDummy);
+      if (aSurf.IsNull())
+      {
+        // skip faces without geometry
+        continue;
+      }
+    }
+
     if (isFwd || isRvs){
       BF.Load(F);
       TopoDS_Iterator aWIter(F);
@@ -306,6 +316,7 @@ static Standard_Real volumePropertiesGK(const TopoDS_Shape     &theShape,
   Standard_Real    anError = 0.;
   TopTools_MapOfShape aFwdFMap;
   TopTools_MapOfShape aRvsFMap;
+  TopLoc_Location aLocDummy;
 
   aVProps.SetLocation(aLoc);
 
@@ -325,6 +336,15 @@ static Standard_Real volumePropertiesGK(const TopoDS_Shape     &theShape,
         continue;
       }
     }
+    {
+      const Handle(Geom_Surface)& aSurf = BRep_Tool::Surface (aFace, aLocDummy);
+      if (aSurf.IsNull())
+      {
+        // skip faces without geometry
+        continue;
+      }
+    }
+
     if (isFwd || isRvs){
         aPropFace.Load(aFace);
 
@@ -444,6 +464,7 @@ static Standard_Real volumePropertiesGK(const TopoDS_Shape     &theShape,
   Standard_Real    anError = 0.;
   TopTools_MapOfShape aFwdFMap;
   TopTools_MapOfShape aRvsFMap;
+  TopLoc_Location aLocDummy;
 
   aVProps.SetLocation(aLoc);
 
@@ -463,6 +484,15 @@ static Standard_Real volumePropertiesGK(const TopoDS_Shape     &theShape,
         continue;
       }
     }
+    {
+      const Handle(Geom_Surface)& aSurf = BRep_Tool::Surface (aFace, aLocDummy);
+      if (aSurf.IsNull())
+      {
+        // skip faces without geometry
+        continue;
+      }
+    }
+
     if (isFwd || isRvs){
         aPropFace.Load(aFace);
 
diff --git a/src/BRepTest/BRepTest_ExtremaCommands.cxx b/src/BRepTest/BRepTest_ExtremaCommands.cxx
index 73ccbfd4d6..3fb1887f90 100644
--- a/src/BRepTest/BRepTest_ExtremaCommands.cxx
+++ b/src/BRepTest/BRepTest_ExtremaCommands.cxx
@@ -138,8 +138,7 @@ static Standard_Integer distmini(Draw_Interpretor& di, Standard_Integer n, const
 
   }
   
-  else di << "probleme\n";
-  //else cout << "probleme"<< endl;
+  else di << "problem: no distance is found\n";
   return 0;
 }
 
diff --git a/tests/bugs/modalg_6/bug27992 b/tests/bugs/modalg_6/bug27992
new file mode 100644
index 0000000000..52271234da
--- /dev/null
+++ b/tests/bugs/modalg_6/bug27992
@@ -0,0 +1,17 @@
+puts "========"
+puts "OCC27992"
+puts "========"
+puts ""
+#################################################
+# Extrema_ExtPS crashes on face without geometric surface
+#################################################
+
+restore [locate_data_file bug27821_nullsurf.brep] a
+
+# check for exceptions for vertex-face
+vertex v 0 0 0
+distmini d v a
+
+# check for exceptions for face-face
+tcopy a b
+distmini d a b
diff --git a/tests/bugs/vis/bug27821 b/tests/bugs/vis/bug27821
index 0e30cfef01..96c3eb2523 100644
--- a/tests/bugs/vis/bug27821
+++ b/tests/bugs/vis/bug27821
@@ -7,8 +7,9 @@ pload MODELING VISUALIZATION
 restore [locate_data_file bug27821_nullsurf.brep] s
 explode s F
 
-# check that sprops does not crash on NULL surface
+# check that sprops and vprops do not crash on NULL surface
 sprops s
+vprops s
 
 # check that AIS_Shape does not crash on NULL surface
 vclear