The values have been determined from past results of pipette leak testing. Specifically, it has been determined that the pressure and detection conditions are sufficient to detect leakage and do not damage pipettes from 2 to 10,000 μL.
If a test is failed very close to the limit of the leak detection conditions, the pipette might have a minute leak or temperature changes after adiabatic expansion of the equipment may have caused a pressure change. In such cases, use a pipette accuracy tester to check if the output volume is correct and then judge whether the pipette is acceptable or not.