The more dependent one becomes on determining parameters of fluid devices and systems through trial runs, the more important it is that these results are comparable. Otherwise, the different products will not be comparable, nor will it be possible to draw conclusions on the behaviour of the devices under other framework conditions.
A prerequisite for such comparability for standardised processes is exact compliance with the standardised framework conditions, and for freely selectable test procedures is the accurate reproduction of the selected framework conditions in the test protocol.