Alumina content is only one input to a refractory-brick specification. A suitable grade depends on the actual furnace zone, hot-face temperature and operating upsets, chemical exposure, mechanical load, abrasion, thermal cycling, brick shape and lining design. A nominal Al₂O₃ percentage is a starting point, not proof of service life or interchangeability.
Before approving a grade or substitution, obtain the offered product's datasheet and agree which test methods, acceptance criteria and documents apply to the project. This guide is a review framework; it does not prescribe a universal grade, temperature margin or campaign life.
1. Define the service envelope
Record the furnace and exact lining zone, not just the industry name. Separate measured operating data from design assumptions. Include normal and upset temperatures; direct flame, slag, alkali vapour or dust exposure; static load; abrasion; heating and cooling frequency; and the current lining's observed damage. The combination matters more than a single headline temperature.
| Input | Project evidence to request | Why it matters |
|---|---|---|
| Location and duty | Furnace drawing, zone name and lining arrangement | The same furnace may contain very different service environments. |
| Thermal profile | Normal and upset temperatures, measurement location and cycling schedule | Peak, duration and cycling must be evaluated together. |
| Chemical and mechanical exposure | Slag or ash analysis where available, alkali sources, abrasion and load description | Composition alone does not establish corrosion or wear resistance. |
| Geometry and installation | Brick drawing, dimensions, jointing and installation method | A technically suitable material still needs a compatible shape and lining design. |
2. Compare product-specific data
Request the exact offered grade and manufacturer's current datasheet. Relevant properties may include declared Al₂O₃ composition, bulk density, apparent porosity, cold crushing strength, load or creep behaviour, thermal-shock test results and chemical-resistance evidence. Ask for the test method, specimen or lot basis and units beside each reported result. Do not fill missing values from a generic grade table.
Where a requirement is mandatory, state its acceptance criterion and required evidence in the purchase specification. If a report is not yet available, mark it supplier confirmation required; do not assume it will accompany every shipment.
3. Keep load-test methods distinct
ASTM C16 describes testing refractories under a specified compressive load at a specified temperature for a specified time. ISO 1893 addresses refractoriness under load under rising temperature. These are not interchangeable labels for one universal RUL figure. Specify the required method, conditions and reported result for the project, and have the technical buyer assess suitability against the actual duty.
Use the standards identified in the contract and verify their applicable editions. A supplier's declared value is meaningful only together with its method and test conditions; this article does not assign a fixed safety margin between test temperature and operating temperature.
4. Compare offers like for like
Align the proposed grade, drawing, quantity, dimensional tolerances, tests and documents, packing, delivery destination, commercial basis and lead time. If two offers use different products or test methods, resolve the difference before treating their numbers or prices as comparable. Higher Al₂O₃ alone does not establish longer service life or lower total cost.
5. Release a project-specific specification
| Check | Record before approval |
|---|---|
| Service basis | Measured and assumed conditions, lining zone and failure history. |
| Offered product | Manufacturer, grade, revision-controlled datasheet and approved drawing. |
| Test and acceptance | Methods, required values, sampling or witnessing rules and who approves results. |
| Documents | Which reports, certificates or batch records are mandatory and when they are due. |
| Supply | Quantity, packing, destination, commercial terms and confirmed lead time. |
Release the final specification only after the responsible buyer or designer reviews the offered product against the actual service conditions. Availability, compliance, documentation and quotation timing must be confirmed for the specific inquiry.
For a project review: Send the furnace and zone, operating data, exposure and cycling conditions, drawing, quantity, destination and mandatory document list. We will check whether a suitable proposal and the required documentation can be supported; this is not a compliance or quotation commitment.
Request a Project Review →Technical references: ASTM C16 and ISO 1893 official scope pages. Product-specific values and supply documents require separate confirmation.