Download PML²/User Guide

Appendix G
New Test Dust Benefits
The new ISO Medium Test Dust (ISO MTD) consists of similar materials to the old
ACFTD, but to minimize particle counting errors, it is of a slightly coarser grade because ACFTD included too many particles smaller than 5µm which gave problems
during testing.
ISO MTD is produced to a standard distribution and stringent quality control procedures, thereby ensuring excellent batch-to-batch repeatability. These procedures,
combined with a revised ISO APC calibration method give:
• A traceable and controlled reference test dust with greatly reduced variation in particle size distribution. This gives the trace-ability required by ISO 9000, QS9000
and similar quality management systems.
• A procedure for determining the performance of APCs so that minimum acceptable
levels can be set by the user.
• Improved calibration techniques and procedures.
• More accurate calibration.
• Improved levels of particle count reproducibility with different equipment.
• More accurate and consistent filter test results.
Effect on Industry
The introduction of ISO MTD has necessitated changes to certain ISO standards.
The standards affected include:
ISO 4402:1991
Hydraulic fluid power
Calibration of liquid automatic particle counters.
ISO 4406:1987
Hydraulic fluid power
Code for defining the level of contamination by solid particles.
ISO 4572:1981
Hydraulic fluid power – Filters
Multi-pass method for evaluating filtration performance of a filter
element.
New ISO Medium Test Dust and its effect on ISO . . .
51