Overview
ISO 8895:2004 specifies a standardized method for determining the cold crushing strength of shaped insulating refractory products at room temperature. The procedure defines sample preparation, equipment, test conditions and calculation of strength so that manufacturers, laboratories and purchasers can obtain repeatable, comparable compression-strength data for insulating refractories.
Key topics and technical requirements
- Scope: Applies to shaped insulating refractories (true porosity ≥ 45% by volume).
- Definition: Cold crushing strength = maximum load (room temperature) divided by loaded area at failure.
- Sampling: Number of items and sampling plan per ISO 5022 or agreed alternative; normally one test piece taken from each standard-size brick.
- Test pieces: Nominal half-brick sizes: 114 × 114 × 76 mm or 114 × 114 × 64 mm; special shapes can be dry-cut to these sizes.
- Dimensional/tolerance checks:
- Load-bearing faces flat within 0.5 mm (checked with rule and 0.5 mm feeler gauge).
- Faces parallel within 1 mm (four height measurements).
- Side perpendicularity within 1 mm (set square check).
- Conditioning: Dry to constant mass in an oven at 110 °C ± 5 °C; cool in a dry atmosphere.
- Apparatus:
- Mechanical or hydraulic compression machine with force measurement accuracy ±2% and spherical seating on one platen; ground platens; deformation measuring device (micrometer).
- Loading rate:
