ASTM C533 Standard Reference
ASTM C533 is the international standard specification for calcium silicate block and pipe thermal insulation. It defines two temperature types:
- Type I: Rated for maximum use temperature of 649°C (1200°F). Mingfa Grade 650 products meet this classification.
- Type II: Rated for maximum use temperature of 927°C (1700°F). Mingfa Grade 1000 and Grade 1100 products exceed this classification.
ASTM C533 also specifies requirements for density, thermal conductivity, compressive strength, flexural strength, linear shrinkage, and moisture content. All Mingfa products can be tested to ASTM C533 upon project request.
LG-Standard Calcium Silicate Products (HCS Series)
Key Takeaways
- HCS series spans 170-250 kg/m3: Thermal conductivity ranges from 0.058 W/m-K (HCS-17) to 0.065 W/m-K (HCS-25) at 100 deg C — select lower density for maximum insulation, higher density where mechanical load-bearing is required.
- ASTM C533 Type I (649 deg C) and Type II (927 deg C): Mingfa Grade 650 meets Type I, while Grades 1000 and 1100 exceed Type II requirements — specify the correct ASTM type in tender documents.
- Five product series available: HCS (general industrial), SCS (high-temp 1100 deg C), MFDJ (aluminum reduction cells), MFGB (steel ladles), MFBL (glass furnaces) — each formulated for specific industry conditions.
- All Mingfa products are manufactured to GB/T 10699 with third-party testing to ASTM C533, EN 14306, and other international standards available on request — custom dimensions and CNC machining offered.
Author's Note: This article draws on Mingfa's 34+ years of calcium silicate R&D and manufacturing experience in Laizhou, Shandong. Technical claims are validated against our in-house laboratory data and published industry standards. About our engineering team
Standard type rated to 1000°C. Low-density calcium silicate insulation board with excellent insulation performance. Bulk density 170-250 kg/m³. Widely used in cement, electrolytic aluminum, steel, and power plant industries for backup insulation behind refractory linings.
| Property | HCS-17 | HCS-20 | HCS-23 | HCS-25 | Test Standard |
|---|---|---|---|---|---|
| Volume Density (kg/m³) | 170 ±10% | 200 ±10% | 230 ±10% | 250 ±10% | GB/T 10699 |
| Flexural Strength (MPa) | ≥0.25 | ≥0.35 | ≥0.45 | ≥0.50 | GB/T 10699 |
| Compressive Strength (MPa) | ≥2.0 | ≥2.3 | ≥2.5 | ≥3.0 | GB/T 5072 |
| Thermal Conductivity (W/m·K) @100°C | ≤0.058 | ≤0.062 | ≤0.064 | ≤0.065 | GB/T 10294 |
| Thermal Conductivity (W/m·K) @400°C | ≤0.100 | ≤0.102 | ≤0.104 | ≤0.107 | GB/T 10294 |
| Maximum Operating Temperature (°C) | 1000 | 1000 | 1000 | 1000 | , |
| Linear Shrinkage (%) | ≤2.0 (1000°C, 16hr soak) | GB/T 10699 | |||
| Moisture Content (%) | ≤5.0 (as manufactured) | GB/T 10699 | |||
References: [1] ASTM C533-17(2023); [2] EN 14306:2015+A1:2018; [3] Mingfa QC Laboratory test data. Full certification details
Products with a maximum operating temperature of 650°C are also available. Contact our technical team for Grade 650 specifications.
LG-High Temperature Calcium Silicate Products (SCS Series)
High-temperature formulation with enhanced thermal stability for applications reaching 1,050-1,100°C. Suitable for burning zone backup insulation in cement kilns and high-temperature industrial furnace linings.
| Property | SCS-25 | Test Standard |
|---|---|---|
| Volume Density (kg/m³) | 250 ±10% | GB/T 10699 |
| Flexural Strength (MPa) | ≥0.50 | GB/T 10699 |
| Compressive Strength (MPa) | ≥3.0 | GB/T 5072 |
| Maximum Operating Temperature (°C) | 1100 | , |
| Linear Shrinkage (%) | ≤2.0 (1050°C, 3hr soak) | GB/T 10699 |
| Thermal Conductivity (W/m·K) @100°C | ≤0.065 | GB/T 10294 |
| Thermal Conductivity (W/m·K) @400°C | ≤0.108 | GB/T 10294 |
| Moisture Content (%) | ≤5.0 (as manufactured) | GB/T 10699 |
Hard Silica-Calcium Composite Brick -- MFDJ Series (Electrolytic Aluminum)
Substrate synthesized from siliceous and calcareous materials through autoclaved hydrothermal compression. Features uniformly distributed micron and nano-sized pores (porosity 85-91%). Used in electrolytic aluminum reduction cells as backup insulation behind the cathode lining.
| Property | MFDJ-30Q | MFDJ-40 | Test Standard |
|---|---|---|---|
| Temperature Grade (°C) | 1000 | 1000 | , |
| Density (kg/m³) | 300 ±10% | 400 ±10% | GB/T 10699 |
| Compressive Strength (MPa) | ≥2.0 | ≥2.5 | GB/T 5072 |
| Linear Shrinkage 900°C × 3h (%) | ≤1.2 | ≤1.2 | GB/T 10699 |
| Thermal Conductivity @900°C (W/m·K) | ≤0.11 | ≤0.11 | YB/T 4130 |
| Porosity (%) | 85-91 | 85-91 | , |
Hard Silica-Calcium Composite Brick -- MFGB Series (Steel Ladle)
High-density formulation for permanent backing in steel ladles. Designed to withstand the mechanical stresses of ladle tilting, crane lifting, and repeated thermal cycling without cracking or crushing. Used behind working refractory linings (alumina-magnesia carbon brick, magnesia-carbon brick).
| Property | MFGB-40 | MFGB-50 | MFGB-60 | Test Standard |
|---|---|---|---|---|
| Temperature Grade (°C) | 1000 | 1000 | 1000 | , |
| Density (kg/m³) | 400 ±10% | 500 ±10% | 600 ±10% | GB/T 10699 |
| Compressive Strength (MPa) | ≥4.0 | ≥5.0 | ≥6.0 | GB/T 5072 |
| Linear Shrinkage 900°C × 3h (%) | ≤1.2 | ≤1.2 | ≤1.2 | GB/T 10699 |
| Thermal Conductivity @900°C (W/m·K) | ≤0.12 | ≤0.13 | ≤0.14 | YB/T 4130 |
Hard Silica-Calcium Composite Brick -- MFBL Series (Glass Furnace)
Specialized formulation for glass melting furnace insulation. Low iron content to minimize discoloration risk. Excellent dimensional stability under prolonged high-temperature exposure typical of glass furnace campaigns (5-15 years).
| Property | MFBL-35 | MFBL-45 | Test Standard |
|---|---|---|---|
| Temperature Grade (°C) | 1000 | 1000 | , |
| Density (kg/m³) | 350 ±10% | 450 ±10% | GB/T 10699 |
| Compressive Strength (MPa) | ≥3.0 | ≥4.0 | GB/T 5072 |
| Linear Shrinkage 900°C × 3h (%) | ≤1.2 | ≤1.2 | GB/T 10699 |
| Thermal Conductivity @900°C (W/m·K) | ≤0.11 | ≤0.12 | YB/T 4130 |
Need a Printable Data Sheet?
Contact our technical team for PDF data sheets with full thermal conductivity curves and standard compliance certificates for your project documentation.
Request Data SheetCustom Sizes Available
All products can be manufactured in custom dimensions and thicknesses. CNC machining available for complex geometries, tapered shapes, and precision cut-outs.
Inquire About Custom SizesKey Takeaways — Reading These Specifications
Before using the tables below, three points determine which grade and property values apply to your application.
- Temperature first, then density. The four product families below are separated by service temperature (1000°C LG-Standard, 1100°C LG-High Temp, plus the industry-specific composite brick series). Within a family, density is selected by mechanical load — never by preference.
- Thermal conductivity must be read at the mean temperature. A single value means nothing without its temperature. The tables give conductivity at 100°C, 200°C, and 400°C mean; interpolate for your actual service condition. The full curve for each grade is available on request.
- These are representative values; batch certificates carry the delivered figures. Every shipment includes a batch test certificate with measured values matching the pallet labels — that certificate, not this page, is the compliance document for your project quality file.
If you need a specific property that is not listed — for example compressive strength at a particular density, or conductivity above 800°C mean — request the full technical data sheet for the grade: contact the engineering team with the grade and property you need, and the data sheet is returned within one business day.
How to Use These Data Sheets in Specification
Procurement teams use these tables in three ways, each requiring a different level of detail from the specification.
Screening a Grade
Match your peak temperature to the family, then check that the density range covers your mechanical duty. This page is sufficient for screening. Typical time: 5 minutes.
Sizing Insulation
For thickness calculation you need conductivity at your service mean temperature and the target heat loss or surface temperature. Use the thickness calculator or request the full conductivity curve.
Writing the Tender Clause
Cite the grade, density, the property value with its test method and mean temperature, and the certificate requirement. Our team reviews tender clauses free of charge — send your draft.
Frequently Asked Questions — Specification Data
Which test methods are the values on this page measured to?
Density per ASTM C302/C303, compressive strength per ASTM C165, flexural strength per ASTM C203, thermal conductivity per ASTM C518 (guarded heat flow meter, with ASTM C177 guarded hot plate available for verification), and linear shrinkage per ASTM C356. European specifications may cite EN 14306 test methods instead; the values are comparable when the mean-temperature basis matches.
Can I get a data sheet for a grade not listed here?
Yes. The tables on this page cover the principal production grades; Mingfa also produces custom densities and formulations for OEM and project-specific orders. Contact the engineering team with the required density, temperature rating, and application, and a data sheet for the closest production grade — or a formulation proposal — is returned within one business day.
How do I verify the delivered material matches these specifications?
Each shipment includes batch test certificates carrying the batch number that also appears on the pallet labels, with measured values for density, compressive strength, thermal conductivity, and linear shrinkage. Compare the certificate values against the specification clause at receiving inspection. For projects requiring independent verification, SGS or Bureau Veritas pre-shipment inspection can be arranged at the factory.
What is the difference between the HCS and SCS series?
HCS (LG-Standard) is the 1000°C family at 170-250 kg/m³ density, the workhorse grade for kiln backing, furnaces, ductwork, and vessels. SCS (LG-High Temp) is the 1100°C family at 250-270 kg/m³, formulated with enhanced xonotlite crystallinity for calcining furnaces, cement burning zones, glass furnace regenerators, and aluminum melting furnace sidewalls. SCS uses a slightly higher conductivity coefficient (0.00012 vs 0.00011) reflecting its denser matrix.
Do you provide CAD files or drawings for the composite brick series?
Yes. For MFDJ (aluminum), MFGB (steel ladle), and MFBL (glass furnace) brick series, dimensioned drawings and DXF files are available for the standard shapes, and custom shapes are produced to customer drawings. Widths, lengths, and radii of curvature are shown in the drawing set; request the specific series drawing from the engineering team.
About the Author — Mingfa Insulation Technical Team
Mingfa Insulation's technical content is authored by our in-house engineering team with 34+ years of specialized experience in calcium silicate R&D and manufacturing. Established in 1991 as a joint venture with the China Building Materials Academy, our team holds ~20 national patents. For technical inquiries, contact lzmfgr@163.com.