Verified answer

Nm^3 refers to gas volume occupied at normal temperature and pressures which are 0 deg c and 14.7 psia. Am^3 refers to gas volume at actual operating conditions of the process. Use P1xV1/T1 = P2xV2/T2 for the conversion.

A Normal Cubic Meter of a gas (Nm^3) is the volume of that gas measured under the standard conditions of 0 degrees Celsius, and 1 atmosphere of pressure. Specifying the "Normal"

conditions of measurement must be done with gases, since the volume of a gas is inversely proportional to its pressure, and proportional to absolute temperature. In other words, because gas volume changes so dramatically with temperature and pressure, we have to establish some "normal" or "known" temperature and pressure conditions in order to be able to compare one person's measurement with another.

Liquids are also universally measured in cubic meters, but not "Normal" cubic meters, since liquids are not subject to the dramatic changes in volume that gases are when temperature and pressure are changed.

My question - are you referring nm3 as normal cubic meter? or is it something else?

Normal cubic meter is the volume of gas at 0C and 1 atm (NTP) or sometime it is also called standard temperature and pressure (STP).

If that is so then use gas law and the fact that 1 mole of gas occupies 22.414 liters at NTP or use the formula:

V = 22.414 x{T/273.15] x [1/P] where T in K and P in atm.

I have been using the above many-many times in my career as a process engineer. Since in chemical plant, use of Nm3 is very common to measure volumetric flow rate of gases.