1. Product Overview & Grade Classification
Understanding calcium silicate board types is the first step in selecting the right insulation. Mingfa classifies its calcium silicate insulation board products into three temperature grades and three density ranges, giving engineers precise control over both thermal and mechanical performance.
Key Takeaways
- Four Product Grades: LG-Standard (1000°C, 170-250 kg/m3), LG-High Temp (1100°C, 250-270 kg/m3), MF-HD High Strength (800-850 kg/m3, ≥13 MPa), and LG-High Purity (Fe2O3 <0.4%) cover the full industrial insulation spectrum.
- ASTM C533 Compliant: All grades manufactured and tested per ASTM C533. Type I (649°C) and Type II (927°C) equivalents available. EN 13501-1 A1 non-combustible, ASTM E84 flame spread 0 / smoke 0.
- Energy Payback: Manufacturing energy of calcium silicate insulation is recouped within the first days of high-temperature service. Over a 20-year lifecycle, the energy savings ratio exceeds 11,000:1 relative to manufacturing energy input.
- Mingfa Differentiator: CNC custom machining from CAD drawings (±0.5mm accuracy). Standard sizes 600x300 up to 1220x2440mm. Factory-direct pricing from Shandong since 1991, 50,000+ tonnes annual capacity, exports to 70+ countries.
Mingfa Lab Verified (2024): All specifications listed are validated through in-house testing per ASTM C518 (thermal conductivity), ASTM C165 (compressive strength), and ASTM C356 (linear shrinkage) at our Shandong QC laboratory. Batch test certificates issued with every order. View our testing methodology
LG-Standard
1000°C Grade
The workhorse calcium silicate board for general industrial insulation
Suitable for rotary kilns, furnace walls, ductwork, and process vessels. Compressive strength ≥2.0 MPa. Thermal conductivity ≤0.058 W/m·K at 100°C mean. Conforms to ASTM C533 Type I and comfortably exceeds its 649°C requirement. Available in HCS-17 (170), HCS-20 (200), HCS-23 (230), and HCS-25 (250) density variants.
LG-High Temp
1100°C Grade
For extreme heat zones where standard boards are insufficient
Exceeds ASTM C533 Type II (927°C) by 173°C. Formulated with enhanced xonotlite crystallinity for superior high-temperature phase stability. Compressive strength ≥2.5 MPa. Linear shrinkage ≤1.5% at 1100°C. Specified for cement burning zones, calcining furnaces, glass furnace regenerators, and aluminum melting furnace sidewalls.
High-Density & Special-Purpose
450-900 kg/m³
Structural insulation for load-bearing and demanding environments
MF-HD (800-850 kg/m³) for steel ladle backup; MFGB series (400-900 kg/m³) for ladle permanent linings and blast furnace stove support; MFBL (600 kg/m³) for glass furnace bottom and crown; MFDJ (300-400 kg/m³) for aluminum reduction cells. All high-density calcium silicate board types maintain the xonotlite crystal structure to 1000°C.
Density classification summary: Low-density (170-270 kg/m³) , maximum thermal efficiency, non-load-bearing, ideal for kiln backing and vessel insulation. Medium-density (270-450 kg/m³) , moderate strength for light structural loads, used in fireproof boards and aluminum cell bricks. High-density (450-900 kg/m³) , high compressive strength for load-bearing applications, steel ladles, glass furnace bottoms, and structural thermal breaks.
2. Technical Specifications , ASTM C533 Compliant
All Mingfa calcium silicate insulation board products are manufactured and tested to ASTM C533, the standard specification for calcium silicate block and pipe thermal insulation. The following table presents representative values for our principal grades.
| Property | LG-Standard HCS-25 | LG-High Temp SCS-25 | MF-HD High Strength | Test Method |
|---|---|---|---|---|
| Max Service Temp | 1000°C | 1100°C | 1000°C | ASTM C533 |
| Bulk Density | 250 ±10% kg/m³ | 270 ±10% kg/m³ | 800-850 kg/m³ | ASTM C302 |
| Compressive Strength | ≥2.0 MPa | ≥2.5 MPa | ≥13 MPa | ASTM C165 |
| Flexural Strength | ≥1.0 MPa | ≥1.2 MPa | ≥5.0 MPa | ASTM C203 |
| Thermal Cond. @ 100°C | ≤0.065 W/m·K | ≤0.065 W/m·K | ≤0.120 W/m·K | ASTM C518 |
| Thermal Cond. @ 200°C | ≤0.072 W/m·K | ≤0.075 W/m·K | ≤0.140 W/m·K | ASTM C518 |
| Thermal Cond. @ 400°C | ≤0.088 W/m·K | ≤0.095 W/m·K | ≤0.185 W/m·K | ASTM C518 |
| Linear Shrinkage (24 h) | ≤1.5% at 1000°C | ≤1.5% at 1100°C | ≤1.5% at 1000°C | ASTM C356 |
| Moisture Content | ≤4% | ≤4% | ≤4% | ASTM C533 |
| Flame Spread / Smoke | 0 / 0 | 0 / 0 | 0 / 0 | ASTM E84 |
| Fire Classification | A1 | A1 | A1 | EN 13501-1 |
Sources: [1] ASTM C533-17(2023) Standard Specification for Calcium Silicate Block and Pipe Thermal Insulation; [2] EN 14306:2015+A1:2018 Factory-made calcium silicate products; [3] GB/T 10699 Calcium silicate thermal insulation. Full certification details
3. Thermal Performance Curves & Worked Example
The thermal conductivity of calcium silicate insulation board follows a predictable linear relationship with temperature. For LG-Standard grade boards, the characteristic equation is:
λ = 0.056 + 0.00011t W/m·K
where t is the mean temperature across the insulation layer in °C
Worked Example , Furnace Wall at 400°C Mean Temperature: A process furnace operates with a hot face of 650°C and a cold face of 150°C. The mean temperature t = (650 + 150) / 2 = 400°C. Applying the formula: λ = 0.056 + (0.00011 × 400) = 0.056 + 0.044 = 0.100 W/m·K.
For a 50mm thick board, the thermal resistance R = thickness / λ = 0.050 / 0.100 = 0.50 m²·K/W. Heat flux q = (650 − 150) / 0.50 = 1,000 W/m². By comparison, an uninsulated 10mm steel shell at similar conditions would lose approximately 8,000-12,000 W/m². The calcium silicate board reduces heat loss by about 88-92%.
For LG-High Temp grade (1100°C), the coefficient b = 0.00012, giving λ = 0.056 + 0.00012t. For MF-HD (800 kg/m³), approximate λ = 0.095 + 0.00018t W/m·K at mean temperatures above 200°C. Full thermal conductivity curves for all grades are provided in the product technical data sheets , contact our engineering team for your specific operating conditions.
4. Standard & Custom Sizes
Mingfa stocks a comprehensive range of standard calcium silicate board dimensions for immediate shipment, and offers CNC-machined custom sizes to match your exact project requirements.
Standard Board Sizes
| Dimension | Typical Use |
|---|---|
| 600 × 300 mm | General furnace & kiln lining |
| 600 × 400 mm | Vessel & tank insulation |
| 1000 × 500 mm | Large-area rotary kiln backing |
| 1220 × 2440 mm | CNC cutting blank, max sheet size |
Thickness Range
Standard thicknesses: 20, 25, 30, 40, 50, 60, 75, 80, 100, 120 mm. Dimensional tolerance: ±1mm on length/width, ±0.5mm on thickness for boards ≤50mm, ±1mm for boards >50mm. Board flatness: ≤1mm per 300mm length. Thicker custom boards up to 150mm are available for specialized applications.
CNC Custom Machining
Complex profiles cut to your CAD drawings (DXF, DWG, or STEP format): beveled edges for curved kiln sections, pipe half-shells, tongue-and-groove interlocking edges, burner tube penetrations, thermocouple well cutouts. CNC accuracy: ±0.5mm. This eliminates on-site cutting, reduces installation time, and minimizes material waste.
5. Industry Application Matrix
Different industries demand different calcium silicate board types. Use this matrix to identify the recommended grade for your application.
| Industry | Application | Recommended Grade | Density (kg/m³) | Max Temp | Key Requirement |
|---|---|---|---|---|---|
| Cement & Lime | Rotary kiln backup insulation | LG-Standard / LG-High Temp | 230-270 | 1000-1100°C | Low thermal conductivity, dimensional stability |
| Steel | Ladle & tundish backup | MF-HD / MFGB-90 | 800-900 | 1000°C | High compressive strength under refractory load |
| Aluminum | Reduction cell bottom & sidewall | MFDJ-30Q / MFDJ-40 | 300-400 | 1000°C | Controlled thermal resistance, fluoride resistance |
| Glass | Furnace bottom, sidewall, crown | MFBL-60 / LG-High Temp | 600 / 270 | 1000-1100°C | Low iron content for glass quality |
| Petrochemical | Fired heater, reformer casing | LG-Standard | 200-250 | 1000°C | Consistent thermal performance, corrosion resistance |
| Power Generation | Boiler casing, HRSG insulation | LG-Standard | 200-250 | 1000°C | Long-term dimensional stability, non-settling |
| Fire Protection | Fire doors, structural steel, barriers | GF-1100 | 350-450 | 1100°C | A1 non-combustible, endothermic dehydration |
| Carbon | Baking furnace backup | Composite Brick | 400-600 | 1000°C | Chemical stability in reducing atmosphere |
| Non-Ferrous Casting | Molten metal contact | LG-High Purity | 230-270 | 1000°C | Fe₂O₃ <0.4%, non-stick to aluminum |
| Marine & Offshore | Exhaust, bulkhead, A60 fire divisions | GF-1100 / Waterproof Board | 350-450 | 1100°C | Water resistance, fire rating, light weight |
6. How to Specify & Order
To receive an accurate quotation from our calcium silicate insulation board supplier team, please provide the following information in your inquiry. Well-specified inquiries receive quotes within 24 hours.
Operating Temperature
Hot face temperature and expected cold face / shell temperature. This determines whether LG-Standard (1000°C) or LG-High Temp (1100°C) is appropriate. Always include your peak operating temperature, not just the average.
Dimensions & Quantity
Board length x width x thickness (mm). Quantity in pieces, square meters, or cubic meters. If you have a continuous area to insulate, provide total area and we will calculate board count. Standard sizes ship faster; custom sizes add 3-5 days to lead time.
Density & Delivery Port
Required density (or we can recommend based on your load conditions). Preferred Incoterm: FOB Qingdao, CIF to your port, or EXW. Include your destination port for accurate freight quotation. Container loading optimization included at no extra charge.
Minimum Order Quantity: 1 pallet (approx. 1-2 m³) for standard boards. Custom sizes: 1 m³ minimum. Free A4 samples available for evaluation. Lead time: 15-20 working days standard, 20-30 days for custom/OEM. Packaging: Fumigated ISPM 15 wooden pallets, UV-stabilized PE wrap, edge protectors, steel/PET strapping.
7. Frequently Asked Questions
What is the difference between calcium silicate board and fiber cement board?
These are fundamentally different materials for different applications. Fiber cement board is a building material , a mixture of cement, cellulose fibers, and sand , used for cladding, soffits, and wet-area wall linings. It contains no xonotlite crystal phase and degrades above 150-200°C as the cement binder dehydrates. Calcium silicate insulation board is an industrial insulation product made from lime and silica reacted in autoclaves to form xonotlite (6CaO·6SiO&sub2;·H&sub2;O) crystals. It is rated to 1000-1100°C, has thermal conductivity around 0.06 W/m·K at ambient (versus ~0.25 for fiber cement), and is designed specifically for high-temperature thermal insulation. Fiber cement board cannot be used in any application requiring fire resistance above 200°C. Calcium silicate board is not suitable as a building cladding material due to its lower flexural strength and moisture sensitivity (it must be kept dry or protected from weather).
How do I cut calcium silicate insulation board?
Calcium silicate board cuts easily with standard woodworking tools. For straight cuts in boards up to 50mm thick, use a carbide-tipped circular saw with a 40-tooth blade , this produces clean, accurate cuts with minimal dust. A jigsaw with a carbide blade handles curved cuts and cutouts. Thin boards (≤25mm) can be scored with a utility knife or carbide scriber and snapped cleanly along the score line. For thicker boards (>50mm), a table saw with dust extraction is recommended. Always use dust extraction and wear a P2/N95 respirator: the dust is a nuisance particulate, not toxic, but can be irritating to the respiratory tract. Cutting generates a fine white powder; wet-cutting (spraying a light mist of water at the cut line) suppresses dust effectively. All cut edges should be sealed if the board will be exposed to moisture , use a light brush coat of sodium silicate solution or specified edge sealant.
Is calcium silicate insulation board moisture resistant?
Standard calcium silicate board is hygroscopic , it absorbs moisture from the air and from direct water contact. The microporous structure (88-92% porosity) readily wicks water by capillary action. This is both a feature and a limitation. In service, the board should be kept dry. If a board becomes wet before installation, it can be dried by gradual heating (ramp up at ≤50°C/hour to 150°C, hold until dry). Wetting does not degrade the xonotlite crystal structure, so mechanical and thermal properties are fully recovered after drying , unlike mineral wool, which can compact and lose insulation value when wet. For applications requiring moisture resistance (outdoor installations, marine, LNG, offshore), Mingfa offers water-repellent treated boards that resist water absorption while maintaining fire classification. These boards are treated with a siloxane-based water repellent integrated during manufacture. For standard boards, protect from rain and standing water during transport, storage, and before the weatherproof cladding or jacketing is applied.
ASTM C533 Standard — Type I vs Type II Calcium Silicate Insulation
ASTM C533 is the international standard specification for calcium silicate block and pipe thermal insulation. It defines two temperature types with distinct density and application requirements. All Mingfa calcium silicate products are manufactured to meet or exceed ASTM C533 specifications.
| Property | Type I (Standard) | Type II (High-Temperature) |
|---|---|---|
| Maximum Use Temperature | 649°C (1200°F) | 927°C (1700°F) |
| Maximum Density | 240 kg/m³ (15 lb/ft³) | 352 kg/m³ (22 lb/ft³) |
| Typical Density Range | 170–250 kg/m³ | 230–900 kg/m³ |
| Typical Compressive Strength | ≥0.7 MPa (≥100 psi) | ≥2.0 MPa (≥290 psi) |
| Typical Flexural Strength | ≥0.35 MPa (≥50 psi) | ≥0.50 MPa (≥72 psi) |
| Linear Shrinkage (at rated temp) | ≤2.0% | ≤2.0% |
| Mingfa Product Series | LG-Standard (HCS-17/20/23/25), Grade 650 | LG-High Temp (SCS-25), MFDJ, MFGB, MFBL series |
| Common Applications | Steam pipes, process vessels, general industrial insulation | Furnace linings, kiln backup, steel ladles, fire endurance structures |
ASTM C533 also specifies requirements for thermal conductivity, moisture content, and hot-surface performance (ASTM C411). Test certificates for specific grades are available on request.
How Our Calcium Silicate Boards Are Manufactured
Understanding the manufacturing process helps buyers evaluate quality consistency. Mingfa's production follows a four-stage process refined over 34 years of continuous operation at our Shandong facility.
1. Slurry Mixing
Amorphous silica, quicklime (CaO), reinforcing fibers, and process additives are combined with water in a high-shear batch mixer. The precise ratio of silica to lime controls the final xonotlite crystal structure. Mingfa's proprietary formulations include infrared masking agents for enhanced thermal performance at elevated temperatures.
2. Molding & Pre-Curing
The slurry is poured into precision molds and heated to initiate gel formation. Within minutes, a wet but self-supporting solid forms. At this stage the material has no crystalline structure — it is an amorphous calcium silicate hydrate gel. Mold dimensions account for subsequent shrinkage during curing and drying.
3. Steam Curing (Induration)
The formed pieces enter a high-pressure steam autoclave (indurator) for several hours at approximately 190°C under saturated steam. This is where the critical chemical reaction occurs: the amorphous gel crystallizes into xonotlite (6CaO·6SiO₂·H₂O), the mineral phase that gives calcium silicate its exceptional thermal stability and mechanical strength. This process operates at relatively low energy — the maximum temperature reached is only about 190°C.
4. Drying, Trimming & Quality Control
Cured boards are dried in controlled ovens to remove free moisture (final moisture content ≤5%). Each board is precision-trimmed to final dimensions, visually inspected for surface defects, and batch-tested for density, thermal conductivity, compressive/flexural strength, and linear shrinkage. Test certificates are issued for every production batch and shipped with the order.
Energy ROI — Manufacturing Energy Recouped Within Days of Service
The energy required to manufacture calcium silicate insulation is remarkably low relative to the energy it saves. Industry studies (Insulation Outlook, NIA) indicate the manufacturing energy for a linear foot of calcium silicate pipe insulation is approximately 154,000 BTU, while the energy saved over one year of service is estimated at 575 times that amount. Over a typical 20-year industrial equipment lifecycle, the energy savings ratio exceeds 11,000:1. This makes calcium silicate one of the most energy-efficient insulation materials from a full lifecycle perspective — the carbon footprint of production is offset within the first days of high-temperature service.
8. Pipe Insulation & Pre-Formed Sections
Beyond flat board stock, Mingfa supplies calcium silicate pipe insulation in pre-formed sections and custom-machined fittings for industrial pipework. These products deliver the same thermal performance and temperature rating as our standard boards, shaped to match pipe geometry for fast, gap-free installation.
Calcium Silicate Pipe Insulation -- Pre-Formed Half Shells
Pre-formed calcium silicate pipe sections are supplied as split half-shells (also called half-rounds or pipe covers) that mate around the pipe circumference. Each pair of half-shells is machined to the exact outer diameter of the specified pipe, so the insulation makes full contact with the pipe surface without air gaps. Standard pipe coverage ranges from 1/2 inch to 24 inches (15mm to 610mm) nominal pipe size, covering everything from small-bore instrument tubing to main steam headers.
The split half-shell design allows insulation to be installed around existing pipework without breaking pipe connections. The two halves are placed around the pipe, secured with galvanized steel wire or stainless steel banding, and the longitudinal joints are staggered between adjacent sections to eliminate through-gaps. For outdoor installations, an aluminum or stainless steel weather jacket is fitted over the calcium silicate sections.
Standard Pipe Sections
Pipe sizes: 1/2 inch to 24 inch (15mm to 610mm) NPS
Insulation thickness: 25mm to 150mm (1 inch to 6 inch)
Section length: 600mm or 1000mm standard
Temperature rating: Up to 1000°C (1100°C on request)
Standard: ASTM C533, ASTM C547 (pipe insulation)
Moulded Fittings
Elbows: 45° and 90° long-radius and short-radius
Tees: Equal and reducing, straight and reducing outlet
Flanges: Split flange covers with bolt clearance
Valves: Custom-machined valve body covers
Reducers: Concentric and eccentric
All fittings match the thermal properties of the pipe section insulation.
For steam service, typical insulation thickness is 50-150mm (2-6 inches) depending on pipe diameter and operating temperature. A 4-inch (100mm) steam main operating at 400°C typically requires 75-100mm of calcium silicate insulation to achieve an outer surface temperature below 55°C for personnel protection. Smaller-bore pipes (below 2 inch / 50mm) operating at the same temperature require proportionally thicker insulation relative to pipe diameter because the surface-area-to-volume ratio increases as pipe diameter decreases.
Insulation Thickness Calculator
Use our free calculator to determine the optimal calcium silicate insulation thickness for your pipe specifications. Enter pipe diameter, operating temperature, and target surface temperature to receive a calculated thickness recommendation based on ASTM C680 heat transfer methodology.
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About the Author — Mingfa Insulation Technical Team
Mingfa Insulation engineering team — 34+ years calcium silicate R&D and manufacturing since 1991. ~20 national patents. lzmfgr@163.com