TECHNICAL STANDARD
ISO 8503-2
Preparation of steel substrates before application of paints and related products — Surface roughness characteristics of blast-cleaned steel substrates — Part 2: Method for the grading of surface profile of abrasive blast-cleaned steel — Comparator procedure
ISO
2012
Current
WHAT DOES THIS STANDARD COVER?
Describes a visual and tactile procedure for grading the surface profile of abrasive blast-cleaned steel using ISO comparators.
WHY IS IT RELEVANT?
Provides a practical field method for determining whether a prepared steel surface corresponds to a defined ISO profile grade.
KEY INSPECTION CONSIDERATIONS
ISO 8503-2 provides a method for grading the surface profile of abrasive blast-cleaned steel using a comparator. The prepared steel surface is assessed against the appropriate ISO surface-profile comparator to establish a profile classification. The comparator should be appropriate for the abrasive/preparation characteristics being assessed, and the comparison should be made directly against the prepared surface. This is a comparative grading method rather than a direct numerical measurement of peak-to-valley height.
WHAT THE STANDARD SHOULD NOT BE USED TO ASSUME
A comparator classification should not automatically be converted into a precise numerical surface-profile measurement. Fine, Medium and Coarse are profile classifications used within the applicable comparison system. Where a project specification requires a quantitative profile result in micrometres, an appropriate quantitative measurement method should be used. Visual surface cleanliness and surface-profile classification remain separate inspection characteristics.
PRACTICAL INSPECTION APPLICATION
ISO 8503-2 may be used following abrasive blast cleaning to classify the resulting surface profile before coating application. Inspectors should assess representative prepared areas and record the resulting profile classification. The result should be compared with the surface-profile requirement established by the project specification or coating manufacturer. Where the profile classification is subsequently used when applying ISO 19840 DFT corrections, the classification and correction should be clearly distinguished in the inspection record.
RELATED TECHNICAL STANDARDS
RELATED TECHNICAL TOPICS
Surface Profile Abrasive Blast Cleaning Dry Film Thickness
RELATED PIL GUIDANCE
Measuring dry film thickness on abrasive blast-cleaned steel is not the same as measuring a coating on a smooth surface. ISO 19840 provides a method for accounting for the influence of surface roughness when verifying coating thickness against the specified nominal dry film thickness.
Practical guidance on assessing abrasive blast-cleaned steel surface profile before protective coating application.
RELATED EXPERTISE
Inspection Technical Consultancy
ABOUT THIS TECHNICAL SUMMARY
Paint Inspection Ltd provides this information to help inspectors, engineers, asset owners and contractors understand the practical relevance of commonly referenced protective coatings standards. This page is PIL technical guidance and does not reproduce or replace the published standard. Users should refer to the current published standard, project specification, coating manufacturer requirements and other applicable contract documents when establishing project requirements or acceptance criteria.
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OFFICIAL STANDARD
PIL technical summaries are intended to explain the inspection relevance of industry standards and do not replace the published document.
STATUS AND SOURCE VERIFICATION
Official ISO catalogue checked 2026-09-23. CMS designation, title and edition checked against the official ISO catalogue record. Record retained as an external standards reference.