Vacuum equipment acceptance
Why ultimate pressure is not enough; how pump-down, pressure rise, helium leak rate, gas load and process logging should be read together.
What I want to see
A pressure-time trace from atmosphere to the acceptance pressure; the gauge range and calibration basis; valve and pump states; an isolated pressure-rise test; helium leak-test conditions and result; and the process gas load where the equipment is intended to operate.
Why one number is weak
Ultimate pressure alone does not separate a tight, clean system from a system limited by outgassing, conductance, trapped volumes, gauge position or a small leak. The useful acceptance picture is the behaviour of the whole vacuum system over time.
Acceptance logic
The acceptance criterion should be written around measurable system behaviour: pump-down, stable base pressure, pressure rise, leak rate, repeatability and process-condition pressure. Supplier component names are supporting information, not the acceptance result.