Calibration and Auditing Procedures
Audit Apparatus
A MiniFlo flow rate transfer device is used as the audit flow rate reference standard; how-ever, the audit standard must be a different device from the one used to calibrate the sampler. Also, to be valid, the MiniFlo audit standard must have been calibrated against a primary standard traceable to the NIST within the last year.

A calibrated digital manometer, Magnehelic® gage, or water manometer is required to measure the pressure drop across the MiniFlo orifice element.

The actual ambient temperature and barometric pressure must also be measured or obtained locally.