diff --git a/FluidDynamics/Components/Orifices/Opening.mo b/FluidDynamics/Components/Orifices/Opening.mo
index 0f279b8196140615bdb6cc9c47d3f34c8ce5ca8a..44fcd8354d5380d14e6035955ebd7e7115d52934 100644
--- a/FluidDynamics/Components/Orifices/Opening.mo
+++ b/FluidDynamics/Components/Orifices/Opening.mo
@@ -29,6 +29,7 @@ model Opening
   Modelica.SIunits.IsentropicExponent gamma "Isentropic exponent";
   Modelica.SIunits.MachNumber M "Mach number at the opening";
   Medium.ThermodynamicState state, state_a, state_b;
+  Modelica.SIunits.MassFraction[Medium.nX] X_a,X_b;
   
   // Imported modules
   TAeZoSysPro.FluidDynamics.Interfaces.FlowPort_a port_a(redeclare package Medium = Medium) annotation (
@@ -77,11 +78,15 @@ equation
     m_flow_i[i] = Vel[i] * Cd * A / N * d[i];       
   end for ;
       
+  /*Ensure compatibility with mono substance medium*/
+  X_a=port_a.d/sum(port_a.d);
+  X_b=port_b.d/sum(port_b.d);
+  
   mX_flow_i = {m_flow_i[i] * TAeZoSysPro.FluidDynamics.Utilities.regStep(
     x = Vel[i], 
     x_small = 1e-14, 
-    y1 = state_a.X, 
-    y2 = state_b.X ) for i in 1:N} ;
+    y1 = X_a, 
+    y2 = X_b ) for i in 1:N} ;
 
   m_flow = sum(m_flow_i) ;
 
diff --git a/FluidDynamics/Sources/Atmosphere.mo b/FluidDynamics/Sources/Atmosphere.mo
index 64830c4a4ba813d6799dae6ca8e283c02043e386..9e7597eead56d68cf0ab03396b5349b0a2f65990 100644
--- a/FluidDynamics/Sources/Atmosphere.mo
+++ b/FluidDynamics/Sources/Atmosphere.mo
@@ -3,6 +3,8 @@ within TAeZoSysPro.FluidDynamics.Sources;
 model Atmosphere
   // Medium declaration
   replaceable package Medium = TAeZoSysPro.Media.MyMedia ;
+  /*Get TAeZoSysPro reference moist air Media*/
+    package Medium_MoistAirTAezo=TAeZoSysPro.Media.Air.MoistAir;
 
 // User defined parameters
   parameter Boolean use_p_in = false "Get the pressure from the input connector" annotation(
@@ -14,12 +16,14 @@ model Atmosphere
   
   parameter Modelica.SIunits.Temperature T = 293.15 "Atmosphere temperature" ;
   parameter Modelica.SIunits.Pressure p = 101325 "Atmosphere Pressure" ;
-  parameter Real RH = 0.6 "Atmosphere relative humidity" ;
+  parameter Real RH = 0.6 "Atmosphere relative humidity - Only accounted if medium == Moist air" ;
+  parameter Modelica.SIunits.MassFraction X[Medium.nX] = Medium.X_default "usefull except for Moist Air";
 
   parameter Integer nPorts = 0 "Number of fluidport" annotation(Dialog(connectorSizing=true));
   // Internal variables
   Medium.ThermodynamicState state ;
 
+  
 // Imported module
   Modelica.Fluid.Interfaces.FluidPort_a[nPorts] Fluidport(redeclare package Medium = Medium) annotation(
     Placement(visible = true, transformation(origin = {-30, 26}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {0, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
@@ -35,6 +39,15 @@ model Atmosphere
     Placement(visible = true, transformation(origin = {-70, -30}, extent = {{-20, -20}, {20, 20}}, rotation = 0), iconTransformation(origin = {-95, -61}, extent = {{-15, -15}, {15, 15}}, rotation = 0)));
 
 protected
+  /*Using TAeZoSysPro medium function ensure no fail with new OM frontend (function exist whatever medium used*/
+  parameter Medium_MoistAirTAezo.MassFraction X_moist[Medium_MoistAirTAezo.nX]= cat(1, {Medium_MoistAirTAezo.massFraction_pTphi(p = p, T = T, phi = RH)}, {1-Medium_MoistAirTAezo.massFraction_pTphi(p = p, T = T, phi = RH)});
+  
+  /*depending on chosen medium, parameter X vector to be adjusted*/
+  parameter Modelica.SIunits.MassFraction X_final[Medium.nX] = if Medium.mediumName=="Moist air" then 
+                                                                X_moist 
+                                                                else
+                                                                X;
+                                                                
   Modelica.Blocks.Interfaces.RealInput T_internal
     "Temperature at ports. Needed to connect to conditional connector";
   Modelica.Blocks.Interfaces.RealInput p_internal
@@ -59,31 +72,22 @@ equation
     RH_internal = RH;
   end if;
 
-  /* detection of the media between a gas with condensable species and a dry gas */
-  if Medium.mediumName == "Moist air" then
-    state = Medium.setState_pTX(p = p_internal, 
-                                T = T_internal, 
-                                X = {Medium.massFraction_pTphi(p = p_internal, T = T_internal, phi = RH_internal)}) ;
+  state = Medium.setState_pTX(p = p_internal, 
+                                T = T_internal,
+                                X=X_final) ; 
   
-  elseif Medium.mediumName == "Air" then
-    state = Medium.setState_pTX(p = p_internal, 
-                                T = T_internal) ;                              
-  else
-  
-    assert(false, "Current Medium is not praticable", AssertionLevel.error);
-    
-  end if ;
 // Ports handover
 // Flowport
   Flowport.T = T_internal;
-  Flowport.d = p_internal / (Medium.gasConstant(state) * T_internal) * state.X ;
+  Flowport.d=Medium.density(state)*X_final;
+
 // Heatport
   Heatport.T = T_internal;
 // Fluidport
   for i in 1:nPorts loop
     Fluidport[i].p = p_internal;
     Fluidport[i].h_outflow = Medium.specificEnthalpy(state);
-    Fluidport[i].Xi_outflow = state.X[1:Medium.nXi];
+    Fluidport[i].Xi_outflow = X_final[1:Medium.nXi];
   end for;
   annotation(
     Icon(coordinateSystem(initialScale = 0.1), graphics = {Ellipse(origin = {-8, 23}, extent = {{-52, 37}, {68, -83}}, endAngle = 360), Text(origin = {-65, 87}, extent = {{-35, 13}, {165, -7}}, textString = "P=%p"), Text(origin = {-37, 33}, extent = {{-63, 47}, {137, 27}}, textString = "T=%T"), Text(origin = {-17, -97}, extent = {{-83, 17}, {117, -3}}, textString = "RH=%RH")}),