ISO 8502-3:2017 remains the most current and updated version of the standard for assessing dust on steel surfaces. While last reviewed and confirmed in
, it is currently active and set for its next review cycle ending in February 2026 Updated ISO 8502-3 Dust Rating Chart The standard provides pictorial ratings for and descriptive classes for Quantity Rating Description of Dust Level Typical Action No particles visible under 10x magnification Very slight; particles visible under 10x but not naked eye Slight; particles just visible with normal vision Pass (Typical spec) Moderate; particles clearly visible (~0.5mm) Often Fail / Re-clean Heavy; particles between 0.5mm and 2.5mm Fail / Re-clean Very Heavy; particles larger than 2.5mm Fail / Re-clean Rösler Blog Key Procedure Steps
The current version of the standard is ISO 8502-3:2017 , which replaced previous editions like the 1992 version. This standard provides a qualitative, pressure-sensitive tape method to assess the quantity and size of dust remaining on blast-cleaned steel surfaces before painting. iTeh Standards ISO 8502-3 Dust Level Classifications The assessment is divided into two primary metrics: Quantity Rating Size Class iTeh Standards Particle Size Description Particle Diameter No particles visible under 10x magnification Visible under 10x magnification, not by naked eye Just visible with normal/corrected vision Clearly visible with normal/corrected vision Large particles clearly visible Very large particles clearly visible Quantity Rating (1–5):
Determined by comparing the tape sample to pictorial references that show the density of dust coverage. Common Acceptance Criteria: Many painting specifications require a maximum Quantity Rating 2 Size Class 2 for high-performance coatings. Rösler Group The Critical Role of ISO 8502-3 in Surface Preparation Introduction
Surface preparation is widely regarded as the most critical stage in any industrial coating project. While visible contaminants like rust and mill scale are often the primary focus, microscopic "invisible" threats like residual dust can be equally devastating to a coating's lifespan. ISO 8502-3 provides the standardized framework necessary to detect and quantify these particles using a simple yet effective pressure-sensitive tape method. ISO - International Organization for Standardization The Impact of Dust on Coating Integrity
Residual dust on blast-cleaned steel acts as a "bond-breaker" between the substrate and the protective coating. Even a thin layer of microscopic particles can reduce adhesive strength, leading to premature delamination or blistering. Furthermore, dust is often hygroscopic; it can trap moisture against the steel, accelerating corrosion under the paint film, often before the asset even enters service. ISO - International Organization for Standardization INTERNATIONAL STANDARD ISO 8502-3
ISO 8502-3 Dust Level Chart is a standard visual tool used in the protective coatings industry to evaluate surface cleanliness after blast cleaning. The most current official version of the standard is ISO 8502-3:2017 , which replaced the original 1992 version. Электронный магазин стандартов Core Functionality
The chart provides a pictorial reference for the "Pressure-Sensitive Tape Method." Inspectors apply a specialized adhesive tape to a prepared steel surface, remove it, and then compare the captured dust against the chart to determine: iTeh Standards Dust Quantity Rating
: A scale from 0 to 5, where 0 is no visible dust and 5 is heavily contaminated. Dust Particle Size Class
: A classification from 0 to 5 based on the diameter of the largest particles. Rösler Group Updated Standard Features (ISO 8502-3:2017) iso 85023 dust level chart pdf updated
The 2017 update maintains the core visual comparison method but ensures consistency with other modern surface preparation standards. INTERNATIONAL STANDARD ISO 8502-3
Important Clarification: There is no official document named "ISO 85023." The correct standard is ISO 8502-3. This is part of the ISO 8502 series, which deals with surface cleanliness tests.
Below is a comprehensive guide on how to use the ISO 8502-3 standard, understand the dust level chart, and where to find the updated PDF resources.
Even with the updated PDF, inspectors make errors. Avoid these:
For legal QA/QC documentation, purchase the official PDF. Do not rely on third-party screenshots.
Q: Is ISO 85023 the same as ISO 8502-3? A: Yes. ISO 85023 is a common typo. The correct number is ISO 8502-3.
Q: Can I get a free PDF of the dust level chart? A: The official ISO chart is copyrighted. However, many training providers offer free summary reference cards. Do not use unofficial PDFs for contractual disputes.
Q: How often is the chart updated? A: ISO standards are reviewed every 5 years. The last confirmed update was 2017. A minor revision may occur in 2027.
Q: What if my customer requires Class 1 but I have Class 2? A: Re-blast the surface, then use compressed air and a vacuum brush. Retest until Class 1 is achieved. ISO 8502-3:2017 remains the most current and updated
Keywords used: iso 85023 dust level chart pdf updated, ISO 8502-3:2017, surface cleanliness, tape test, dust class 1 2 3, coating inspection, abrasive blasting, steel preparation.
The most current version of the ISO 8502-3 standard is ISO 8502-3:2017, which was last reviewed and confirmed in 2022 and remains the active version for 2026. It defines a qualitative "pressure-sensitive tape method" to assess dust quantity and size on blast-cleaned steel. ISO 8502-3 Dust Level Assessment
The standard uses two primary metrics to grade surface cleanliness: Quantity Rating (pictorial) and Size Class (descriptive). 1. Dust Particle Size Classes
The average size of the dust particles is assigned a class from 0 to 5 based on visibility and diameter: Particle Description Typical Diameter 0 No particles visible under 10x magnification 1 Visible under 10x magnification (not to naked eye) 2 Just visible with normal vision 50 μm – 100 μm 3 Clearly visible with normal vision Up to 0.5 mm 4 Clearly visible 0.5 mm – 2.5 mm 5 Clearly visible 2. Dust Quantity Ratings
The quantity of dust is assessed by comparing the tape to a pictorial reference chart (0–5 scale): Rating 0: Tape is clear; no dust visible. Rating 1–4: Increasing concentrations of dust particles.
Rating 5: Tape exhibits overall discoloration (reddish-brown/black), often caused by microscopic dust from specific abrasives. Standard Inspection Procedure
The most current version of the standard is ISO 8502-3:2017, which details the "pressure-sensitive tape method" for assessing dust on blast-cleaned steel surfaces. This assessment involves comparing a used tape sample against pictorial ratings to determine both dust quantity and particle size. ISO 8502-3 Dust Classification Chart
The standard provides two main evaluation scales from 0 to 5. Rating/Class Dust Quantity Assessment Dust Particle Size Description 0 No dust visible on tape No particles visible under 10x magnification 1 Lowest dust quantity
Visible under 10x magnification, but not with normal vision ( 2 Generally accepted limit Just visible with normal vision ( 3 Moderate dust; requires re-test Clearly visible with normal vision (up to 4 High dust quantity Particles between 5 Excessive dust quantity Particles larger than Official Resources & PDFs Common Mistakes When Using the ISO 8502-3 Dust
While the full official standard must be purchased directly from the International Organization for Standardization (ISO), summary charts and data sheets are often provided by equipment manufacturers:
Official PDF Sample: A preview of the ISO 8502-3:2017 standard is available via iTeh Standards.
Assessment Guide: A practical instructional PDF for field use is hosted by Paint Test Equipment Test Kit Reference: Commercial kits like the Elcometer 142 Go to product viewer dialog for this item. include physical comparator boards based on these classes. Key Application Tips
Acceptance Level: In most industrial coating specifications, Rating 2 is the maximum allowable level for both quantity and size; anything higher typically requires re-cleaning.
Procedural Rule: Always discard the first three turns of a new tape roll to ensure no environmental contamination affects the test.
Visual Aid: Because this is a qualitative visual test, using an illuminated 10x magnifier is required for Class 0 and 1 assessments. Elcometer 142 ISO 8502-3 Dust Tape Test Kit
If you need a PDF for educational purposes, general reference, or to include in a method statement, you can obtain it through the following channels:
Recommendation for Contractors: While PDF charts are useful for training, always use an ISO 8502-3 certified Comparator Card (often included with Testex tape or Elcometer kits) for final inspection to avoid disputes over adhesion failures.