Key Update from 2017: The new chart emphasizes that even if quantity is Class 2, if any particle exceeds 100 µm, the overall rating drops to Class 3.
The standard specifies a simple, low-tech method using a specialized "dust tape kit."
Equipment Needed:
The "chart" refers to the pictorial references used to classify the dust collected on a piece of tape. The test involves pressing a specialized adhesive tape onto the blasted surface, removing it, and then comparing the tape to the chart.
The assessment is based on two factors:
Meta Description: Need the latest ISO 85023 dust level chart? This guide explains the updated PDF version, how to read the chart, test methods (tape/bristle), and why it matters for surface cleanliness before coating.
There has been some confusion regarding updates to this standard.
The ISO 8502-3 standard, titled "Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method)," is a critical benchmark in industrial coating to ensure surface cleanliness. The latest version is ISO 8502-3:2017, which replaced the older 1992 and 2000 versions. The Role of ISO 8502-3 in Surface Preparation
Surface cleanliness is the foundation of any long-lasting protective coating. Dust on blast-cleaned steel can significantly reduce the adhesion of organic coatings and promote corrosion by trapping moisture. The ISO 8502-3 standard provides a standardized method to quantify and categorize this dust, allowing inspectors to make objective "pass/fail" decisions before paint application. Assessment Methodology: The Tape Test
The standard employs a qualitative approach known as the "pressure-sensitive tape method". iso 85023 dust level chart pdf updated
Application: A standardized adhesive tape is pressed onto the cleaned steel surface using a weighted roller or consistent thumb pressure.
Removal: The tape is peeled off, carrying any residual dust with it.
Observation: The tape is then placed on a contrasting background (typically white or black) for visual comparison against pictorial references. The Dust Level Chart: Ratings and Classes
The ISO 8502-3 chart uses two primary metrics to evaluate cleanliness:
Dust Quantity Rating (0–5): This is a pictorial rating representing the density of dust particles on the tape. Rating 0: Surface is free of dust.
Rating 1–2: Trace to light dust (often acceptable for high-performance coatings).
Rating 3–5: Significant to heavy dust (typically requiring re-cleaning).
Dust Size Class (0–5): These descriptive classes categorize the average size of the dust particles. Class 0: Particles not visible under 10x magnification.
Class 1–2: Fine particles visible under magnification but difficult to see with the naked eye. Key Update from 2017: The new chart emphasizes
Class 3–5: Large particles easily visible to the naked eye. Practical Application and PDF Reporting
Industrial inspectors often use standardized reporting templates to document these results. You can find current resources and PDF examples on platforms like Scribd (e.g., ISO 8502-3 Dust Level Chart PDF) or via official standards bodies like the ISO Store for the ISO 8502-3:2017 full document. INTERNATIONAL STANDARD ISO 8502-3
ISO 8502-3 Dust Level Chart: The Complete Guide to Surface Cleanliness
Proper surface preparation is the single most critical factor in determining the longevity of a protective coating. The ISO 8502-3:2017 standard provides the definitive qualitative method—known as the Dust Tape Test—for assessing the presence of loose dust on blast-cleaned steel surfaces before painting.
Understanding the dust quantity ratings and size classes is essential for inspectors to ensure paint adhesion and prevent premature corrosion. ISO 8502-3 Dust Level Ratings
The standard evaluates dust based on two primary metrics: Quantity Rating (the density of particles) and Size Class (the diameter of particles). 1. Dust Quantity Ratings (Density)
Dust quantity is determined by comparing the pressure-sensitive tape to pictorial references provided in the ISO 8502-3 standard. Description Common Acceptance Level 0 No particles visible under 10x magnification. Always Accepted 1 Very small amount of dust; barely visible. Always Accepted 2 Low amount; particles just visible. Industry Standard Limit 3 Moderate amount; clearly visible. Often Rejected 4 Large amount; easily noticeable. 5 Very large amount; dense coverage. 2. Dust Particle Size Classes
While quantity is the most common requirement in coating specifications, the size of the particles is also classified. ISO 8502-3 testing | Industrial Physics
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 specifies a simple, low-tech method using
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 ISO 8502-3:2017 standard remains the current global benchmark for assessing dust on steel surfaces before painting. While it was last confirmed in 2022, the methodology and pictorial references established in the 2017 update continue to serve as the industry standard for quality control in 2024 and beyond.
Understanding the ISO 8502-3 dust level chart is critical for coating inspectors and surface preparation teams to ensure proper adhesion and prevent premature corrosion. Core Components of the ISO 8502-3 Chart
The assessment is split into two primary qualitative ratings: Quantity and Size. 1. Dust Quantity Ratings (1–5)
This visual rating compares the density of dust particles on a test tape against pictorial references.
Based on the request for updated content regarding the ISO 8502-3 dust level chart, the following information summarizes the current standard, how the chart works, and where the PDF resources fit in.
The standard uses a scale from 1 to 5 to denote the density of particles: