diff --git a/Documentation/Examples/geometry_example.cc b/Documentation/Examples/geometry_example.cc
index 528c0d4436a2ccf00f226642fc5eda20ce8afd55..a8ae9c51bbdfe0dfb1d398fd6c4d980e2e918603 100644
--- a/Documentation/Examples/geometry_example.cc
+++ b/Documentation/Examples/geometry_example.cc
@@ -8,11 +8,8 @@
 #include <typeinfo>
 #include <cstdlib>
 
-using namespace phys::units; 
-using namespace phys::units::io; // support stream << unit
-using namespace phys::units::literals; // support unit literals like 5_m;
-
 using namespace fwk;
+using namespace fwk::literals; // support unit literals like 5_m;
 
 int main()
 {
@@ -29,7 +26,7 @@ int main()
     Point const p1(root, {0_m, 0_m, 0_m}); // the origin of the root CS
     Point const p2(cs2, {0_m, 0_m, 0_m}); // the origin of cs2
     
-    Vector<length_d> const diff = p2 - p1; // the distance between the points, basically the translation vector given above
+    Vector<fwk::length_d> const diff = p2 - p1; // the distance between the points, basically the translation vector given above
     auto const norm = diff.squaredNorm(); // squared length with the right dimension
     
     // print the components of the vector as given in the different CS
@@ -46,8 +43,8 @@ int main()
     
     
     // let's try parallel projections:
-    auto const v1 = Vector<length_d>(root, {1_m, 1_m, 0_m});
-    auto const v2 = Vector<length_d>(root, {1_m, 0_m, 0_m});
+    auto const v1 = Vector<fwk::length_d>(root, {1_m, 1_m, 0_m});
+    auto const v2 = Vector<fwk::length_d>(root, {1_m, 0_m, 0_m});
 
     auto const v3 = v1.parallelProjectionOnto(v2);
     
diff --git a/Documentation/Examples/helix_example.cc b/Documentation/Examples/helix_example.cc
index c365c83b0fd300b3fac3fa23040031fc8883a7b0..4d6ccfe8c93612e8765d9caf4163f068afd11132 100644
--- a/Documentation/Examples/helix_example.cc
+++ b/Documentation/Examples/helix_example.cc
@@ -8,9 +8,8 @@
 #include <cstdlib>
 #include <iostream>
 
-using namespace phys::units;
-using namespace phys::units::io;       // support stream << unit
-using namespace phys::units::literals; // support unit literals like 5_m;
+using namespace fwk;
+using namespace fwk::literals; // support unit literals like 5_m;
 
 int main() {
   fwk::CoordinateSystem root;
diff --git a/Framework/Particles/ParticleProperties.h b/Framework/Particles/ParticleProperties.h
index 7f2f433d925b5febe49909fcf1269eba8db1d8bb..c9acdb44cbac3f0457adeb8daf067d1f9defddb9 100644
--- a/Framework/Particles/ParticleProperties.h
+++ b/Framework/Particles/ParticleProperties.h
@@ -43,7 +43,7 @@ namespace fwk {
     }
 
     auto constexpr GetElectricCharge(Code const p) {
-      return GetElectricChargeNumber(p) * (phys::units::e);
+      return GetElectricChargeNumber(p) * (fwk::constants::e);
     }
 
     auto const GetName(Code const p) {
diff --git a/Framework/Particles/pdxml_reader.py b/Framework/Particles/pdxml_reader.py
index 6c1fc3bd95339c0d6366452705d57d0bc7aabefc..9a5e5220f621c21b324601f900e7144a584625c1 100755
--- a/Framework/Particles/pdxml_reader.py
+++ b/Framework/Particles/pdxml_reader.py
@@ -278,7 +278,7 @@ def gen_classes(pythia_db):
         string += "  public:\n"
         string += "   static Code GetCode() { return Type; }\n"
         string += "   static quantity<energy_d> GetMass() { return masses[TypeIndex]; }\n"
-        string += "   static quantity<electric_charge_d> GetCharge() { return phys::units::e*electric_charge[TypeIndex]/3; }\n"
+        string += "   static quantity<electric_charge_d> GetCharge() { return fwk::constants::e*electric_charge[TypeIndex]/3; }\n"
         string += "   static int GetChargeNumber() { return electric_charge[TypeIndex]/3; }\n"
         string += "   static std::string GetName() { return names[TypeIndex]; }\n"
         string += "   static Code GetAntiParticle() { return AntiType; }\n"
@@ -303,9 +303,8 @@ def inc_start():
     string += "#include <array>\n"
     string += "#include <cstdint>\n"
 #    string += "#include <iostream>\n\n"
-    string += "using namespace phys::units;\n"
-    string += "using namespace phys::units::literals;\n\n"
     string += "namespace fwk { \n\n"
+    string += "using namespace literals; \n"
     string += "namespace particle { \n\n"
     string += "typedef int16_t PDGCode;\n\n"
     return string
diff --git a/Framework/Particles/testParticles.cc b/Framework/Particles/testParticles.cc
index 8b219a3eded171c52a0df47b09de7821b9b128e0..a48858b991f01e9623ee2884819c6706c98011af 100644
--- a/Framework/Particles/testParticles.cc
+++ b/Framework/Particles/testParticles.cc
@@ -6,9 +6,7 @@
 
 #include <fwk/ParticleProperties.h>
 
-// using namespace phys::units;
-// using namespace phys::units::literals;
-
+using namespace fwk::literals;
 using namespace fwk::particle;
 
 TEST_CASE("Particles", "[Particles]") {
@@ -18,9 +16,9 @@ TEST_CASE("Particles", "[Particles]") {
   SECTION("Data") {
     REQUIRE(Electron::GetMass() / 0.511_MeV == Approx(1));
     REQUIRE(Electron::GetMass() / GetMass(Code::Electron) == Approx(1));
-    REQUIRE(Electron::GetCharge() / phys::units::e == Approx(-1));
-    REQUIRE(Positron::GetCharge() / phys::units::e == Approx(+1));
-    REQUIRE(GetElectricCharge(Positron::GetAntiParticle()) / phys::units::e ==
+    REQUIRE(Electron::GetCharge() / fwk::constants::e == Approx(-1));
+    REQUIRE(Positron::GetCharge() / fwk::constants::e == Approx(+1));
+    REQUIRE(GetElectricCharge(Positron::GetAntiParticle()) / fwk::constants::e ==
             Approx(-1));
     REQUIRE(Electron::GetName() == "e-");
   }
diff --git a/Framework/Units/PhysicalConstants.h b/Framework/Units/PhysicalConstants.h
index 7935c3962e83b14fe27dd0f60176faac75b6eedf..a4e8b0ce6e644734a3dbeb627c568a458d6ffdfb 100644
--- a/Framework/Units/PhysicalConstants.h
+++ b/Framework/Units/PhysicalConstants.h
@@ -64,13 +64,12 @@ namespace phys {
 
 namespace fwk {
 
-  using namespace phys;
+  // using namespace phys;
   using namespace phys::units;
 
+  namespace constants = phys::units::constants;
+  
 } // namespace fwk
 
 #endif // PHYS_UNITS_PHYSICAL_CONSTANTS_HPP_INCLUDED
 
-/*
- * end of file
- */
diff --git a/Framework/Units/PhysicalUnits.h b/Framework/Units/PhysicalUnits.h
index b5ee98bff29baf44223e0aa02aded7e7fb7cc091..3403cafac6765c630ea3a7d64041a59d6f0c3fd4 100644
--- a/Framework/Units/PhysicalUnits.h
+++ b/Framework/Units/PhysicalUnits.h
@@ -1,8 +1,9 @@
 #ifndef _include_PhysicalUnits_h_
 #define _include_PhysicalUnits_h_
 
+#include <fwk/PhysicalConstants.h>
+
 #include <phys/units/io.hpp>
-#include <phys/units/physical_constants.hpp>
 #include <phys/units/quantity.hpp>
 
 /**
@@ -11,29 +12,27 @@
  * Define _XeV literals, alowing 10_GeV in the code.
  */
 
-/*using namespace phys::units::io;
-using namespace phys::units::literals;*/
-
 namespace phys {
   namespace units {
     namespace literals {
-      QUANTITY_DEFINE_SCALING_LITERALS(eV, energy_d, magnitude(eV))
+      QUANTITY_DEFINE_SCALING_LITERALS(eV, energy_d, magnitude(constants::eV))
     }
   } // namespace units
 } // namespace phys
 
 namespace fwk {
 
-  using namespace phys;
   using namespace phys::units;
-  // using namespace phys::units::literals;
+  //namespace literals = phys::units::literals;    
   
-  using Length = phys::units::quantity<phys::units::length_d, double>;
-  using Time = phys::units::quantity<phys::units::time_interval_d, double>;
-  using Speed = phys::units::quantity<phys::units::speed_d, double>;
-  using Frequency = phys::units::quantity<phys::units::frequency_d, double>;
-  using ElectricCharge = phys::units::quantity<phys::units::electric_charge_d, double>;
-  using Energy = phys::units::quantity<phys::units::energy_d, double>;
+  //namespace quantity {
+    using Length = phys::units::quantity<phys::units::length_d, double>;
+    using Time = phys::units::quantity<phys::units::time_interval_d, double>;
+    using Speed = phys::units::quantity<phys::units::speed_d, double>;
+    using Frequency = phys::units::quantity<phys::units::frequency_d, double>;
+    using ElectricCharge = phys::units::quantity<phys::units::electric_charge_d, double>;
+    using Energy = phys::units::quantity<phys::units::energy_d, double>;
+    //} // namespace quantity
 
 } // end namespace fwk
 
diff --git a/Framework/Units/testUnits.cc b/Framework/Units/testUnits.cc
index e963c6796ee5d746abc0c29bd006c5d07c394d0e..a1f52e15d39ee493fe16732deb01352caf32d1bb 100644
--- a/Framework/Units/testUnits.cc
+++ b/Framework/Units/testUnits.cc
@@ -1,73 +1,73 @@
-#define CATCH_CONFIG_MAIN  // This tells Catch to provide a main() - only do this in one cpp file
+#define CATCH_CONFIG_MAIN // This tells Catch to provide a main() - only do this in one
+                          // cpp file
 #include <catch2/catch.hpp>
 
 #include <fwk/PhysicalUnits.h>
 
 #include <array>
 
-using namespace phys::units;
-using namespace phys::units::literals;
+using namespace fwk;
+using namespace fwk::literals;
 
-TEST_CASE( "PhysicalUnits", "[Units]" ) {  
+TEST_CASE("PhysicalUnits", "[Units]") {
 
   SECTION("Consistency") {
-    REQUIRE( 1_m/1_m == Approx(1) );
-    //REQUIRE_FALSE( 1_m/1_s == 1 ); // static assert
+    REQUIRE(1_m / 1_m == Approx(1));
+    // REQUIRE_FALSE( 1_m/1_s == 1 ); // static assert
   }
 
   SECTION("Constructors") {
     auto E1 = 10_GeV;
-    REQUIRE( E1==10_GeV );
+    REQUIRE(E1 == 10_GeV);
 
-    quantity<phys::units::length_d> l1 = 10_nm;
-    
-    quantity<phys::units::length_d> arr0[5];
+    fwk::Length l1 = 10_nm;
+
+    fwk::Length arr0[5];
     arr0[0] = 5_m;
-    
-    quantity<phys::units::length_d> arr1[2] = { {1_mm}, {2_cm} };
 
-    std::array<quantity<phys::units::energy_d>, 4> arr2; // empty array
-    
-    std::array<quantity<phys::units::energy_d>, 4> arr3 = { 1_GeV, 1_eV, 5_MeV };
+    fwk::Length arr1[2] = {{1_mm}, {2_cm}};
+
+    std::array<fwk::Energy, 4> arr2; // empty array
+
+    std::array<fwk::Energy, 4> arr3 = {1_GeV, 1_eV, 5_MeV};
   }
-  
+
   SECTION("Powers in literal units") {
-    REQUIRE( 1_s/1_ds == Approx(1e1) );
-    REQUIRE( 1_m/1_cm == Approx(1e2) );
-    REQUIRE( 1_m/1_mm == Approx(1e3) );
-    REQUIRE( 1_V/1_uV == Approx(1e6) );
-    REQUIRE( 1_s/1_ns == Approx(1e9) );
-    REQUIRE( 1_eV/1_peV == Approx(1e12) );
-    REQUIRE( 1_A/1_fA == Approx(1e15) );
-    REQUIRE( 1_mol/1_amol == Approx(1e18) );
-    REQUIRE( 1_K/1_zK == Approx(1e21) );
-    REQUIRE( 1_K/1_yK == Approx(1e24) );
-
-    REQUIRE( 1_A/1_hA == Approx(1e-2) );
-    REQUIRE( 1_m/1_km == Approx(1e-3) );
-    REQUIRE( 1_m/1_Mm == Approx(1e-6) );
-    REQUIRE( 1_V/1_GV == Approx(1e-9) );
-    REQUIRE( 1_s/1_Ts == Approx(1e-12) );
-    REQUIRE( 1_eV/1_PeV == Approx(1e-15) );
-    REQUIRE( 1_A/1_EA == Approx(1e-18) );
-    REQUIRE( 1_K/1_ZK == Approx(1e-21) );
-    REQUIRE( 1_mol/1_Ymol == Approx(1e-24) );    
+    REQUIRE(1_s / 1_ds == Approx(1e1));
+    REQUIRE(1_m / 1_cm == Approx(1e2));
+    REQUIRE(1_m / 1_mm == Approx(1e3));
+    REQUIRE(1_V / 1_uV == Approx(1e6));
+    REQUIRE(1_s / 1_ns == Approx(1e9));
+    REQUIRE(1_eV / 1_peV == Approx(1e12));
+    REQUIRE(1_A / 1_fA == Approx(1e15));
+    REQUIRE(1_mol / 1_amol == Approx(1e18));
+    REQUIRE(1_K / 1_zK == Approx(1e21));
+    REQUIRE(1_K / 1_yK == Approx(1e24));
+
+    REQUIRE(1_A / 1_hA == Approx(1e-2));
+    REQUIRE(1_m / 1_km == Approx(1e-3));
+    REQUIRE(1_m / 1_Mm == Approx(1e-6));
+    REQUIRE(1_V / 1_GV == Approx(1e-9));
+    REQUIRE(1_s / 1_Ts == Approx(1e-12));
+    REQUIRE(1_eV / 1_PeV == Approx(1e-15));
+    REQUIRE(1_A / 1_EA == Approx(1e-18));
+    REQUIRE(1_K / 1_ZK == Approx(1e-21));
+    REQUIRE(1_mol / 1_Ymol == Approx(1e-24));
   }
 
   SECTION("Powers and units") {
-    REQUIRE( 1 * ampere / 1_A == Approx(1e0) );
-    REQUIRE( mega * bar / bar == Approx(1e6) );
+    REQUIRE(1 * ampere / 1_A == Approx(1e0));
+    REQUIRE(mega * bar / bar == Approx(1e6));
   }
 
   SECTION("Formulas") {
-    const quantity<phys::units::energy_d> E2 = 20_GeV * 2;
-    REQUIRE( E2==40_GeV );
-    
-    const double lgE = log10(E2/1_GeV);
-    REQUIRE( lgE==Approx(log10(40.)) );
+    const fwk::Energy E2 = 20_GeV * 2;
+    REQUIRE(E2 == 40_GeV);
+
+    const double lgE = log10(E2 / 1_GeV);
+    REQUIRE(lgE == Approx(log10(40.)));
 
     const auto E3 = E2 + 100_GeV + pow(10, lgE) * 1_GeV;
-    REQUIRE( E3==180_GeV );
+    REQUIRE(E3 == 180_GeV);
   }
-  
 }