using System;

using System.Web;

public class Program

{

    public static string HTMLEncodeSpecialChars(string text)

    {

      System.Text.StringBuilder sb = new System.Text.StringBuilder();

      foreach (char c in text){

        if(c>127) // special chars

          sb.Append(String.Format("&#{0};",(int)c));

        else

          sb.Append(c);

      }

      return sb.ToString();

    }

    public static void Main()

    {

        var a = HTMLEncodeSpecialChars("≥ 60ml/min");

        Console.WriteLine(a);

        var b = HttpUtility.HtmlDecode(a);

        Console.WriteLine(b);

    }

}