Overview
ISO 12678-2:1996 - Refractory products - Measurement of dimensions and external defects of refractory bricks - Part 2: Corner and edge defects and other surface imperfections - defines practical, repeatable methods to measure external surface defects of refractory bricks. It covers apparatus, definitions and step‑by‑step measurement procedures for corner defects, edge defects, craters, cracks, protrusions, indentations and fins. This part deals only with external defects (not internal defects) and does not set acceptance or rejection criteria.
Key topics and technical requirements
- Scope and limitations
- Applies to standard brick shapes referenced to ISO 5019 (parts 1–6) and ISO 5417 unless otherwise agreed.
- Procedures are for routine inspection; internal defects are excluded.
- Definitions
- Corner defect (dimensions a, b, c), edge defect (e, f, g), crater (max/min diameter and depth), hairline crack (width ≤ 0.2 mm), open crack (length > 10 mm and width > 0.2 mm), surface crazing, fins, protrusions and indentations.
- Required apparatus
- Linear measuring device (steel tape, calipers, graticule) - calipers accurate to 0.1 mm; steel tape accurate to ~1 mm.
- Steel straightedge (min. 5 mm thick), breakage‑defect sizers (slots uncovering 2 mm), feeler gauges, depth gauge with 3 mm probe, measuring wedges (graduated; types with 0.5 mm or 0.1 mm increments).
- Measurement methods
- Corner and edge defects measured with straightedge, breakage‑defect sizer(s) and tape or calipers; crater diameters D and d and depth h measured with tape and depth gauge; protrusion heights with straightedge and wedges; crack lengths with tape and widths with graticule or feeler gauges.
- Accuracy requirements: most linear dimensions to the nearest millimetre; finer features measured to specified accuracies (see standard for table of measurement accuracy).
- Reporting
- Test report must include testing establishment, date/place, reference to ISO 12678-2, material designation, batch/sample size, inspected properties, results and inspector signature.
Applications and users
- Who uses it
- Refractory manufacturers, quality control and inspection labs, procurement and acceptance inspectors, plant maintenance teams, and standards bodies.
- Practical uses
- Routine quality inspection of refractory bricks before shipment or installation, documenting surface imperfections for supplier claims, supporting dimensional conformity checks, and preparing consistent inspection reports for industrial furnaces, steelmaking, cement and kiln linings.
Related standards
- ISO 12678 (other parts) - general series for refractory product measurement
- ISO 5019 (brick dimensions, parts 1–6) and ISO 5417 (rotary kiln bricks) - referenced shape/dimension standards used with ISO 12678-2
Keywords: ISO 12678-2:1996, refractory bricks, corner defects, edge defects, craters, protrusions, breakage-defect sizer, surface imperfections, measurement methods, quality inspection.