Division 8.2.3.1 Periodic verifications

It shall be made sure that the balance and PM-stabilization environments meet the periodic verifications in point 8.1.12. The reference filter shall be weighed just before weighing test filters to establish an appropriate reference point (see section details of the procedure in point 8.1.12.1). The verification of the stability of the reference filters shall occur after the post-test stabilisation period, immediately before the post-test weighing.