# ISO 8502

Source: https://coatmentor.com/standards/iso-8502/ · Updated 2026-10-04

Tests for surface cleanliness before painting: dust, salts and condensation.

**Publisher**: ISO

**Area**: Surface preparation and conditions

ISO 8502 holds the tests that find what the eye cannot judge: dust, soluble salts and the risk of condensation.

## The parts an inspector meets

- **Part 3:** dust. Clear tape is pressed onto the blast-cleaned surface. The dust is rated for quantity (1–5, against pictures) and particle size class (0–5).
- **Part 4:** the probability of condensation, from air temperature, humidity and steel temperature. The dew point formula comes from here.
- **Part 6:** the Bresle method: deionised water in an adhesive patch dissolves the soluble salts on a known area.
- **Part 9:** the conductivity of that water, measured in the field and converted to a surface density of salt.

The specification sets the limits: a maximum dust rating and size class, a maximum salt level, and the dew point margin.

**Use it:** [Dew point calculator](https://coatmentor.com/calculators/dew-point/)

**37** practice items in the members area mention ISO 8502 (CIP 1: 18 · CIP 2: 9 · FROSIO written: 10).

## Related

- **Concepts:** [Soluble salts and the Bresle test](https://coatmentor.com/learn/soluble-salts/) · [Dew point and the 3 °C margin](https://coatmentor.com/learn/dew-point/)
- **Standards:** [ISO 8501](https://coatmentor.com/standards/iso-8501/) · [ASTM E337](https://coatmentor.com/standards/astm-e337/)
- **Defects:** [Blistering](https://coatmentor.com/defects/blistering/) · [Amine blush](https://coatmentor.com/defects/amine-blush/) · [Blushing (solvent blush)](https://coatmentor.com/defects/blushing/) · [Contamination and inclusions](https://coatmentor.com/defects/contamination/)

## About this page

**Also published openly:** [Elcometer 142 dust tape kit instructions](https://downloads.elcometer.com/PDFs/InstructionManuals/English/142.pdf) · [DeFelsko: grading dust tape tests to ISO 8502-3](https://www.defelsko.com/resources/how-to-perform-and-grade-dust-tape-tests-in-accordance-with-iso-8502-3).

This page describes the subject of ISO 8502 in our own words; it does not reproduce the standard. For the full text, buy the current edition from ISO. Checked on 2026-10-04; errors go in the [corrections log](https://coatmentor.com/method/). CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.