what is an accepted measurement uncertainty in natural gas distribution system quantity metering

[ehuds]

Hello,
I am looking for publications and/or private experience and/or examples and/or calculation programs
Thanks.
Ehud

 

[EmmanuelTop]

Ehud,

Measurement uncertainty is normally defined in the delivery/sales gas contracts. Suitable metering systems are chosen accordingly.


Dejan IVANOVIC
Process Engineer, MSChE

 

[LittleInch]

In really large scale systems I've seen required "accuracy" or rather "uncertainty" be listed as no more than 1.1% of energy. The calculation comes from something like AGA 8 to handle all the pressure and temperature compensations and adjustments, never mid the accuracy and repeatability of the relevant instruments.

"Domestic, very low pressure distribution on the other hand.

The UK gas meter regulations from the 1980's state that it should not differ by more than 2% of volume.

The latest European spec divides things into an upper and lower band for flow and different turndown factors. The Maximum Permitted Error (MPE) is either 2% (low flow band) or 1% (higher flow band) for a meter with a turndown of 1:20. for meters with bigger turndowns it is 3% or 1.5%. If errors are all on one side of measurement (same sign) from base then they should not exceed 1% or 0.5% respectively.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.