Appendix G
50
New ISO Medium Test Dust and its effect on ISO . . .
New ISO Medium Test Dust and its effect
on ISO Contamination Control Standards
When General Motors gave advance warning to the International Standards Organiza-
tion (ISO) that it was intending to stop the production of AC Fine Test Dust (ACFTD),
work commenced immediately on finding an improved replacement dust. ACFTD was
used extensively within the fluid power and automotive industries for calibrating Au-
tomatic Particle Counters (APCs) and for the testing of components.
APCs are used for testing oil filters, and also for contaminant sensitivity testing of hy-
draulic components. For 25 years, APCs have been the main stay in the measurement
of solid particles in hydraulic fluids. The growth in demand for measuring fluid clean-
liness in a variety of industrial processes, including fluid power, has resulted in APCs
moving from the laboratory environment out into the factory. In fact, they are now a
critical part of many production processes. It is therefore essential that the data they
provide is both accurate and consistent.
Calibration
ACFTD has been used as an artificial contaminant since the 1960s and its original
particle size distribution was determined using an optical microscope. This particle
size distribution subsequently formed the basis of ISO 4402, the method for calibrat-
ing APCs. Due to the limitations of that method of measurement, the particle size
distribution was questioned below about 5µm. It was also not traceable to any national
standard of measurement - a critical requirement for today’s quality management sys-
tems.
There was also an absence of formal controls over the distribution of the test dust, and
batch-to-batch variability was much greater than is acceptable nowadays.
ISO therefore defined the requirements for the replacement for ACFTD and asked the
National Institute of Standards and Technology (NIST) in the USA to produce a stan-
dard, traceable reference material. The new dust’s particle size distribution has been
accurately determined with the aid of modern scanning electron microscope and image
analysis techniques.
Summary of Contents for PML2
Page 1: ...PML Analyser UserGuide 200 052 EN www mpfiltri co uk ...
Page 6: ...6 Introduction Figure 1 ...
Page 38: ...38 Warranty ...
Page 62: ...Appendix K 62 Fault Finding ...