# Accuracy of a flow measuring instrument

Gold Member
I have an instrument whose spec. sheet mentions Accuracy as 2% of FSD.

The scale runs from 0 to 1000 Litres per hour. Does this mean if I check the instrument versus a gold standard calibrating instrument at a flow of 500 Litres per hour (which is our typical flow) the absolute error can be as large as 2% of 1000? i.e. 20 Litres?

If so, then the allowable error at 500 LPH nominal flow becomes 4%.

Am I doing this right?