This part of ISO 21360 specifies methods for measuring the volume flow rate, base pressure, water vapour

tolerance, power consumption, and the lowest start-up temperature of positive displacement vacuum pumps,

which discharge gas against atmospheric pressure and with a usual base pressure <10 kPa.

In this part of ISO 21360, it is necessary to use the determinations of volume flow rate and base pressure

specified in ISO 21360‑1.

This part of ISO 21360 also applies to the testing of other types of pumps which can discharge gas against

atmospheric pressure, e.g. drag pumps.