Normal m³/hr (Nm³/hr) and m³/hr are both units of volumetric flow rate, but they represent different conditions:

• Nm³/hr stands for "Normal Cubic Meters per Hour" and refers to the flow rate of a gas at standard temperature and pressure (STP), which is typically defined as 0°C and 1 atmosphere (101.325 kPa).
• m³/hr simply stands for "Cubic Meters per Hour" and refers to the flow rate of a gas or liquid at any temperature and pressure.

To convert Nm³/hr to m³/hr, you need to know the actual temperature and pressure of the gas. You can use the following formula:

m³/hr = Nm³/hr * (P_STP / P_actual) * (T_actual / T_STP)

where:

• P_STP is the standard pressure (101.325 kPa)
• P_actual is the actual pressure of the gas
• T_STP is the standard temperature (273.15 K)
• T_actual is the actual temperature of the gas

If you don't have the actual temperature and pressure of the gas, you can assume standard conditions and the conversion factor is simply 1:

m³/hr = Nm³/hr

In summary, if you're dealing with gas flow rates at standard conditions, you can use Nm³/hr and m³/hr interchangeably. However, if you're working with gas flow rates at non-standard conditions, you'll need to use the conversion formula to accurately convert between the two units.