The standard categorizes dust contamination using two distinct metrics: (how much dust is present) and Size (how large the particles are). A complete specification will always state both limits (e.g., "Max Quantity 2, Max Size Class 3"). 1. Dust Quantity Ratings (0 to 5)
The most recent update to ISO 8502-3 (valid as of 2024/2025) introduces several clarifications to the dust level chart. If you have been using older reference charts (pre-2020), note these critical changes:
The ISO 8502-3 method is a qualitative pressure-sensitive tape test used to measure the amount and size of dust particles remaining on a cleaned surface, typically before coating application. It is particularly crucial for steel surfaces that have been abrasive blast-cleaned. Key Components of the Standard iso 85023 dust level chart pdf updated
The ISO 8502-3 standard defines the following dust levels:
: Trace to light dust (often acceptable for high-performance coatings). Dust Quantity Ratings (0 to 5) The most
Part of a broader series focused on surface cleanliness, ISO 8502-3 uses a to qualitatively assess loose particulate matter. It functions as a rapid "pass/fail" mechanism or a permanent record of surface quality prior to industrial paint application. The evaluation relies on two primary data streams:
Small amount of dust; particles are visible but sparse. Key Components of the Standard The ISO 8502-3
Clear tape. No dust particles visible under 10x magnification.
Visually compare an area of the tape equal to the reference area shown in the standard's Figure 1. Record the corresponding quantity rating.
The procedure for using the chart is standardized to ensure reliable results: