What is the allowable error for repeatability and reproducibility？

  According to ISO13320:2009, the error of repeatability and reproducibility is evaluated by three typical particle sizes of D10, D50 and D90. The deviation of D50 is allowed to be no more than 3%, and the deviation of D10 and D90 is not more than 5%. The standard also stipulates the conditions for repeatability and reproducibility verification: first, the ratio of the particle size distribution D90 to D10 of the sample used is 1.5-10, second, at least three consecutive tests, and third, for samples with a particle size less than 10um, the allowable range of repeatability and reproducibility errors can be doubled, that is, the deviation of D50 is allowed to be no more than 6%, and the deviation of D10 and D90 is no more than 10%.