Standard · Surface preparation and conditions
ISO 8502
Tests for surface cleanliness before painting: dust, salts and condensation.
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
37 practice items in the members area mention ISO 8502 (CIP 1: 18 · CIP 2: 9 · FROSIO written: 10).
Related
Try it in an exam-style question. The free readiness check shows the question style, explains every answer and gives you a dated study plan.
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Also published openly: Elcometer 142 dust tape kit instructions · DeFelsko: grading dust tape tests to 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. CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.