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# HOW TO CONVERT M3/hr.( CUBIC METER PER HOUR) TO Nm3/hr. (NORMAL CUBIC METER PER HOUR)?

CONVERT M3/hr TO Nm3/hr
by Robstaa
Member since:
10 September 2008
Total points:
1,260 (Level 3)

Normalising any measurement requires that the STP (standard temperature and pressure) values be defined 1st as they are often different for different countries ie

USA

Tref = 20 or 25 degC (depending on the measurement standards)
Pref = 29.92 inHg

Europe, Australia, NZ, UK

Tref = 273.15 degK = 0 degC
Pref = 1013 hPa

Converting raw m3/hr to Nm3/hr is a simple application of Charles Law multiplying ratios of true and ref Temp and Pressure values as follows.. we can ignore the hr term as it is applied throughout

if m3=1 and Pactual=1025hPa and Tactual=21degC

Nm3 = m3 x Pactual/Pref x (273.15+Tref)/(273.15+Tactual)

Nm3 = m3 x Pactual/1013 x (273.15+0)/(273.15+21)

Nm3 = 1 x 1025/1013 x 273.15/294.15

Nm3 = 1 x 1.01185 x 0.92861

Nm3 = 0.939 m3

### Source(s):

Been doing this everyday for 19yrs
what is hpa in ihe formula?
i know Pa & kpa

1 hpa=? pa or kpa
hPa is = 100Pa,
1kPa = 10hPa

BTW we use capital P for Pa as it is from a persons name "Pascal" Same as A for Ampere, V for Volta, N for Newton. Wherever you see a SI unit in CAPS its come from someones name.

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• Member since:
10 November 2007
Total points:
832,800 (Level 7)
A normal cubic meter (Nm³) is the metric expression of gas volume at standard conditions and it is usually defined as being measured at 0°C and 1 atmosphere of pressure.

So you need to know the temperature and pressure conditions of the gas if you want to convert to "normal cubic meter".

PS, M is never used as an abbreviation for meter. Only m is used.

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