Quote Originally Posted by hassanfadil View Post
Thanks for the informative reply
Yes that's what am asking but my problems are:
1) the API standard shows that Uncertainty should be +/- 0.027 with 95% level of confidence, which can be achieved by: The typical requirement is that a meter must repeat within +/- 0.05%
in 5 consultative runs. For example, a repeatability of +/ - 0.12% in 10 consecutive runs or a repeatability of +/- 0.17% in 15 consecutive
runs both meet +/- 0.027% at 95% confidence level.
2) The API standard does not show the linearity requirement.
It's true that API do not define the linearity numbers that should go with the meter. (Probably the reason for this could be with the diffent physical properties for the liquid ( e.g.: phase, viscosity etc) & the variety of fluids fluids to meter (crude, lpg, lng,other refined products) it could be difficult to define a particular number for linearity). Hence for majority of liquid custody transfer applications, this linearity requirement is defined in the contract between buyer & seller with their mutual agreement. Secondly it also depends on the what r the best linearity meters available in the market. For a turbine meter / ultrasonic meter the linearity is typically +/-0.15%.

I hope this answers your query.