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As a policy of continual improvement, RMF reserves the right to alter the specification without prior notice.
201.028 REV 1 Date of Issue: 18 June 2018
7.3 Test Duration
The set Test Duration is the amount of time for which particle counts are accumulated, before the test result is
updated. The default of 120 seconds is likely to be suitable for most applications. However it is possible to set
other values.
A shorter time enables the unit to respond more quickly to variations in cleanliness. This may be desired in order
to reduce the product test time in a production line situation.
A longer test time enables the unit to average out variations in cleanliness and produce a more stable result. This
is especially true for the larger particle sizes. In clean systems there are very few of these, so a large amount of
fluid needs to be sampled in order to count a statistically significant number.
Another factor is the flow rate. This can be traded off with cycle time, since a higher flow allows the same amount
of fluid to be sampled in a shorter time.
"Very Clean" Systems
– Longer test times / higher flows are needed.
"Normal" or "Dirty" Systems
– Shorter test times or lower flows are acceptable.
Figure 7.1 Test time needed for reliable indication by ISO code