ContaminationSensor – CS 2000 series
HYDAC Filtertechnik GmbH
en
Page 68
BeWa CS2000 3117721e en.doc
2008-03-28
14
Cleanliness classes - brief overview
14.1 Cleanliness
class - ISO 4406:1999
In ISO 4406:1999 particle counts are determined cumulatively, i.e. > 4 µm
(c)
, >6
µm
(c)
and >14 µm
(c)
(manually by filtering the fluid through an analysis membrane or
automatically using particle counters) and allocated to measurement references.
The goal of allocating particle counts to references is to facilitate the assessment of
fluid cleanliness ratings.
In 1999 the "old" ISO 4406:1987 was revised and the size ranges of the particle
sizes undergoing analysis redefined. The counting method and calibration were also
changed.
This is important for the user in his everyday work: even though the measurement
references of the particles undergoing analysis have changed, the cleanliness code
will change only in individual cases. When drafting the "new" ISO 4406:1999 it was
ensured that not all the existing cleanliness provisions for systems had to be
changed.
14.1.1 ISO 4406 table
Allocation of particle counts to cleanliness classes:
Number of particles / 100 ml
Number of particles / 100 ml
Class
More than
Up to (and
including)
Class
More than
Up to (and
including)
0
0 1
15
16,000 32,000
1
1
2
16
32,000
64,000
2
2 4
17
64,000 130,000
3
4
8
18
130,000
250,000
4
8 16
19
250,000 500,000
5
16
32
20
500,000
1,000,000
6
32 64
21
1,000,000 2,000,000
7
64
130
22
2,000,000
4,000,000
8
130 250
23
4,000,000 8,000,000
9
250
500
24
8,000,000
16,000,000
10
500
1,000
25
16,000,000 32,000,000
11
1,000
2,000
26
32,000,000
64,000,000
12
2,000 4,000
27
64,000,000 130,000,000
13
4,000
8,000
28
130,000,000
250,000,000
14
8,000 16,000
