European basis for natural gas heating values

[nickwigen]

I want to verify information on how most of the world measures heating value of combustion gases. Outside North America most places use the Lower Heating Value v.s. our Higher Heating Value. My question is what temperature and pressure is used in the EU when establishing the LHV. I think it's 1 atmosphere and 0°C but I cannot find a reference.

 

[WalterMoreno]

nickwigen,

As I can see in EN standards for appliances like Room Heaters and Storage water heaters, the basis is dry gas 1013.25 mbar and 15°C.
These standards are EN 613:2000, Heaters and EN 89 Water Heaters.
The standard for test gases is EN 437.

Luck,
WalterMoreno

 

[radomir]

I believe Mr Moreno is right.

Pressure of 1013.25 mbar is in fact a Standard Atmosphere (1 atm = 760 mmHg), and 15 deg C is some miracle temperature value used for ages in all European standards. A cubic meter of any pure gas under those conditions is designated as a Normal Cubic Meter (Nm^3) of that gas and all physical characteristics of gases are usualy defined for the 1 Nm^3, including LHV and HHV.

 

[TD2K]

Miller states that in Europe, standard conditions are 14.69595 psia (101.325 kPa) and 60 deg F. Normal conditions are at the same pressure but 0 deg C (32F).

Interestingly, Miller states in 1981 in the US for ISO 5024 for natural gas, standard temperature is 15C/59F but also concedes that other temperature and pressure bases widely apply.

I remember 'normal' (which got me looking through my reference materials) from high school chemistry as being 0 deg C.

 

[nickwigen]

TD2K brings up an interesting point on "Standard" and "Normal". If I read the post corectly Normal is 0°C and Standard is 15°C. On my airflow calcs we designate them as "nM3" but use the 15°C as a basis. I guess that should actually be Standard. The fan performance data from the German Manufacturer refers to Normal but I'm pretty sure they base it on 15° not 0°. Looks like I'll include lots of notes on the temperature basis.

Thanks to everyone.

 

[MortenA]

TD2K and nickwigen:

Its correct that is seems like a deliberate trap the definition of Sm3 and Nm3

nickwigen is correct:

Nm3 is 1 atm (14.7 psia) and 0 deg C
Sm3 is 1 atm and 15 deg C. Please note that 60 deg F is 15.6 deg C. Nobody that i have asked knwe why 15 and not 16 deg C is used.

To add more trouble: In the UK almost on Sm3 is used while in Norway almost only Nm3 is used. In Denmark we mix

Best Regards

Morten