Overview
ISO 5017:2025 specifies a laboratory method for determining bulk density, apparent porosity and true porosity of dense shaped refractory products. Applicable to standard refractory bricks, special shapes and pre-cast items, the standard defines sampling, specimen preparation, vacuum impregnation with an immersion liquid and a sequence of weighings to calculate porosity and bulk density. The method requires the true density to be determined in accordance with ISO 5018 and includes guidance on precision and reporting.
Key topics and requirements
- Scope: Applies to shaped refractories with fixed geometry; can also be used for unshaped refractories after specimen preparation per ISO 1927-5. Shaped insulating products use ISO 5016 for bulk density and true porosity.
- Principle: Weigh test pieces dry, after vacuum impregnation determine apparent immersed mass, then weigh soaked mass in air; calculate bulk density, apparent porosity and true porosity using these masses and the true density (ISO 5018).
- Sampling and specimens:
- A sample consists of at least four items (e.g., bricks) - follow a sampling plan agreed by parties (example: ISO 5022).
- Recommended at least two test pieces per item; pieces should be taken randomly from items.
- Test pieces: prisms or cylinders, remove as-manufactured surfaces (typical removal ≈1 mm). Bulk volume should be 50–200 cm3; longest/shortest dimension ratio ≤ 2:1.
- Apparatus and conditions:
- Drying oven (110 °C ± 5 °C, or 150 °C ± 10 °C for MgO products).
- Balance with ±0.01 g accuracy and arrangement for suspended weighing.
- Evacuating equipment to reach absolute pressure ≤ 2 500 Pa for vacuum impregnation.
- Immersion liquid: cold distilled/deionized water for non-reactive materials or suitable organic liquid for water-sensitive materials; paraffin options noted with caveats.
- Procedure specifics: Vacuum soak cycle (evacuate, introduce liquid, maintain reduced pressure, allow penetration) and sponging/drying practices; reject cracked specimens.
- Quality: Annex on precision and bias and requirements for reporting test conditions and any deviations.
Applications and users
ISO 5017:2025 is used for:
- Quality control and acceptance testing of refractory bricks and shaped products
- Material selection and process control in steel, foundry, cement and ceramic industries
- Laboratory testing in commercial materials testing labs and R&D groups
- Contractual testing and conformity assessment between manufacturers and users
Typical users: refractory manufacturers, metallurgical plants, materials engineers, test laboratories and procurement/specification teams.
Related standards
- ISO 5018 - Determination of true density (required input)
- ISO 5016 - Bulk density and true porosity for shaped insulating refractories
- ISO 1927-5 / ISO 1927-6 - Preparation and testing of unshaped refractories
- ISO 5022 - Sampling plans for refractory products
Keywords: ISO 5017:2025, dense shaped refractory products, bulk density, apparent porosity, true porosity, vacuum impregnation, refractory bricks, materials testing.