What is the difference between STP and NTP
Standard temperature and pressure, abbreviated STP, refers to nominal conditions in the atmosphere at sea level. This value is important to physicists, chemists, engineers, and pilots and navigators.
Standard temperature is defined as zero degrees Celsius (0 0C), which translates to 32 degrees Fahrenheit (32 0F) or 273.15 degrees kelvin (273.15 0K). This is essentially the freezing point of pure water at sea level, in air at standard pressure.
Normal Temperature and Pressure - is defined as air at 20oC (293.15 K, 68oF) and 1 atm ( 101.325 kN/m2, 101.325 kPa, 14.7 psia, 0 psig, 29.92 in Hg, 760 torr). Density 1.204 kg/m3 (0.075 pounds per cubic foot