April 1992, ISO/TC22 members approved new work item proposal N1712 Performance Testing of Filters – Definition of Test Dust. Later that year ISO/TC22/SC7/WG3 began work on a rough draft, which would evolve through stages of ISO Standard Development.

ISO 12103-1 ROAD VEHICLES – TEST DUST FOR FILTER EVALUATION

Part 1: Arizona Test Dust was published, First Edition, 15 December 1997. It specifies four grades of test dust including dust description, designation, particle size distribution, particle size analysis procedure, and chemical content. The intent in producing a separate standard for the description of test dust was to provide a simple and accurate test dust reference for use in other standards or documents where test dust use is required. Future revisions of ISO 12103-1 will accommodate changes in technology affecting test dust manufacturing processes and insure product consistency for years to come.

Four grades of test dust are designated in ISO 12103-1, a description of each is as follows:

• ISO 12103-1,A1 Ultrafine Test Dust is nominal 0-10 micron size. It was originally developed for testing automotive cabin air filters. Although it is not currently specified as a suitable contaminant for cabin air filters, it is used as a test contaminant for fuel system components, water filter performance evaluation, and other custom applications. ISO Ultrafine test dust is a milled and classified product resulting in a sub micron content that is lower than that found in ISO 12103-1,A2 Fine Test Dust.
• ISO 12103-1,A2 Fine Test Dust is nominal 0-80 micron size. ISO Fine Dust is identical to SAE Fine Test Dust produced by Powder Technology Inc. prior to formation of this Standard. The basis for acceptable particle size limits specified per ISO 12103-1, A2 were derived from analysis of eight batches of SAE Fine Test Dust manufactured by Powder Technology, Inc. between 1992 and 1994. A view of volume differential particle size data indicates a bi-modal distribution with approximate peaks at 4 and 20 micron size. The bi-modal aspect of this product traces back to the original roller analysis specification of Fine Test Dust shown in former revisions of SAE J726 Specification.
• ISO 12103-1,A3 Medium Test Dust is nominal 0-80 micron size with a lower 0-5 micron content than ISO 12103-1,A2 Fine Test Dust. Medium Test Dust is identical to former SAE 5-80 Micrometer Test Dust specified in SAE J1858: Full flow lubricating oil filters multipass method for evaluating filtration performance (now relaced by ISO 4548-12). The basis for acceptable particle size limits specified per ISO 12103-1,A3 were derived from multiple samples of two prior batches of SAE 5-80 Micrometer Test Dust manufactured by Powder Technology Inc. Samples from only two batches were used because only two batches of this type dust were produced prior to 1994 when ISO 12103-1 particle size limits were determined.
• ISO 12103-1,A4 Coarse Test Dust is nominal 0-180 micron size. ISO Coarse Test Dust is identical to SAE Coarse Test Dust produced by Powder Technology Inc. prior to formation of this Standard. The basis for acceptable particle size limits specified per ISO 12103-1,A4 were derived from analysis of 8 batches of SAE Coarse Test Dust manufactured between 1992 and 1994.
• Multisizer IIe Particle Size Analyzer. The Multisizer IIe analyzer measures particles individually by volume (mass). Particles for analysis are suspended in an electrolyte solution. The suspension is stirred and drawn through an aperture using a vacuum source. Particles are measured as they pass through the aperture. Particle size limits specified per ISO 12103-1 are expressed as cumulative volume percent smaller than and listed as follows:

GRAPHICAL COMPARISON OF ISO 12103-1 TEST DUST GRADES

Based on ISO 12103-1 Specified Limits Median (Cumulative Volume)