The accuracy level and allowable error of the flowmeter within the specified flow range should meet the requirements of Table 1. The flowmeter error indicates the relative indication error. For the flowmeter error indication used for instantaneous flow indication, quoted error can also be used. The allowable error series should meet the requirements of Table 1. The accuracy grade is no longer given in the bidding document of the verification result, and the allowable error expression should be used instead. Mark FS after the allowable error, such as ±0.5%FS.

In a calibration of a flowmeter, the method of indicating the error of the flowmeter should be given according to one of the accuracy grade and the quoted error; for the flowmeter that uses the combination of relative indication error and quoted error to indicate the error, a calibration is in progress A method should also be used to express the error.