37
As a policy of continual improvement, STAUFF reserves the right to alter the specification without prior notice.
201.031
Date of Issue: 06 November 2018
Figure 6.24
ISO4406:1999 Alarm Levels
ISO4406:1999 represents cleanliness using codes for the number of particles greater than 4, 6 and
14µm. These codes can be used as limits for the alarms by selecting the ISO4406:1999 test Format and
then entering values as required. As an extension to ISO4406:1999 it is also possible to specify codes
for the other measured sizes too. If this is not needed then the entries can be left blank.
NAS1638 Alarm Levels
Figure 6.25
NAS1638 can be used by selecting this as the test Format. The headings and boxes for the available
settings change appropriately. NAS1638 represents the overall cleanliness level as a single code, this
being the highest of the individual codes generated for each defined particle size. Hence we have the
option of setting a limit on this overall contamination class (the Basic Class), or we can set individual
limits on any combination of the classes for the defined particle size ranges.
AS4059E Table 2 Alarm Levels
Figure 6.26
AS4059E Table 2 uses letters instead of numbers to indicate the particle size range, so the settings are
labelled appropriately. The standard specifies ways to represent a cleanliness level using only a subset