A calcium silicate board is a rigid, asbestos-free microporous insulation panel engineered for back-up thermal barriers in industrial furnaces, kilns, boilers, and fireproof building structures. Highland Refractory manufactures two temperature grades — 650°C for standard cement kiln and boiler back-up lining, and 1000°C for extreme smelting furnace and glass tank insulation — with bulk density from 230 to 800 kg/m3 and thermal conductivity as low as ≤0.08 W/(m·K).
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This guide goes beyond basic descriptions. It explains:
What calcium silicate board is and why it performs the way it does
The major industrial and construction applications
Why calcium silicate board is chosen over other insulation materials
Typical working temperatures and performance expectations
Practical selection guidance based on real operating conditions
By the end of this article, you will clearly understand where calcium silicate board performs best, where its limitations are, and how to select the right grade for your application.
Calcium silicate board is a cement-free, high-temperature insulation board manufactured through a hydrothermal reaction between calcium compounds and silica.
Calcium oxide (CaO) or calcium hydroxide
Silica (SiO₂), typically from quartz sand
Reinforcing fibers (organic or inorganic)
Small amounts of additives to control crystal growth
During production, these materials react under high temperature and pressure to form crystalline calcium silicate phases such as tobermorite or xonotlite, which give the board its strength and thermal stability.
This non-asbestos product, primarily made from a blend of silica (SiO₂) and calcium (CaO) along with reinforcing fibers, is widely used across multiple industries for its remarkable heat-resistant properties.
Calcium silicate board combines several properties that are rarely found together in a single insulation material:
High service temperature (typically up to 1000–1100°C)
Low thermal conductivity
High compressive strength compared with fibrous insulation
Excellent dimensional stability
Non-combustible and fire-resistant
Easy to cut, drill, and install
Because of this balance, calcium silicate board is used both as a thermal insulation layer and as a structural or semi-structural fireproof panel.
One of the most common uses of calcium silicate board is in industrial boilers and power generation systems.
Typical applications include:
Boiler outer wall insulation
Steam pipe insulation backing layers
Heat recovery systems
Turbine insulation enclosures
Why calcium silicate board is used:
Withstands continuous operating temperatures of 500–900°C
Maintains shape under mechanical load
Reduces heat loss and improves energy efficiency
Provides a rigid surface for cladding systems
In power plants, calcium silicate board is often used as a back-up insulation layer, combined with refractory castables or bricks on the hot face.
Calcium silicate board is widely used in furnaces across many industries, including steel, aluminum, glass, and ceramics.
Common furnace applications:
Back-up insulation behind refractory bricks
Furnace door insulation panels
Heat treatment furnace walls
Annealing furnaces
Reheating furnaces
Key benefits in furnaces:
Reduces shell temperature
Improves thermal efficiency
Provides flat, stable insulation surfaces
Simplifies furnace construction and maintenance
Because of its rigidity, calcium silicate board is often preferred over ceramic fiber boards where mechanical strength and dimensional accuracy are important.
In cement plants and lime kilns, calcium silicate board is commonly used in:
Preheater insulation systems
Kiln hood and duct insulation
Cooler back-up insulation
These environments demand materials that can tolerate high temperature fluctuations, dust, and mechanical vibration.
Calcium silicate board performs well as a secondary insulation layer, improving energy efficiency while protecting steel structures.
In aluminum smelting and processing facilities, calcium silicate board is used for:
Furnace back-up insulation
Launder insulation systems
Heat treatment furnaces
Holding furnaces
Its low thermal conductivity helps reduce heat loss, while its rigidity allows it to maintain shape under continuous operation.
This non-asbestos product, primarily made from a blend of silica (SiO₂) and calcium (CaO) along with reinforcing fibers, is widely used across multiple industries for its remarkable heat-resistant properties.
Beyond industrial insulation, calcium silicate board is widely used in fire protection systems.
Typical uses include:
Fire-rated partition walls
Fireproof ceilings
Shaft and duct enclosures
Fire barriers in commercial buildings
Because calcium silicate board is non-combustible, it does not release toxic fumes during fire exposure and helps maintain structural integrity.
In certain designs, calcium silicate board is used to protect:
Steel columns and beams
Cable trays
Equipment enclosures
Its ability to resist fire while maintaining mechanical strength makes it suitable for passive fire protection systems.
In marine and offshore environments, calcium silicate board is commonly used for:
Fireproof bulkheads
Engine room insulation
Offshore platform fire barriers
Its resistance to fire and corrosion, combined with structural rigidity, makes it suitable for demanding marine standards when properly protected against moisture.
Understanding what calcium silicate board is used for also requires knowing when it is not the best choice.
| Property | Calcium Silicate Board | Ceramic Fiber Board |
|---|---|---|
| Max service temperature | ~1100°C | 1400–1600°C |
| Mechanical strength | High | Low |
| Rigidity | Rigid | Semi-rigid |
| Moisture resistance | Moderate | Excellent |
| Best use | Structural insulation | Lightweight hot face insulation |
Calcium silicate board is preferred where strength and stability are needed, while ceramic fiber excels in ultra-high-temperature, lightweight applications.
This non-asbestos product, primarily made from a blend of silica (SiO₂) and calcium (CaO) along with reinforcing fibers, is widely used across multiple industries for its remarkable heat-resistant properties.
Microporous materials offer extremely low thermal conductivity but are expensive and mechanically fragile. Calcium silicate board offers a cost-effective balance between insulation efficiency and durability.
Fire bricks can withstand higher temperatures and mechanical abuse, but they conduct more heat. Calcium silicate board is often used behind fire bricks to reduce heat loss.
Fire Clay Brick: alumina content of 30% to 48%, refractory temperature above 1400 degrees Celsius.
| Application | Typical Temperature | Recommended Role |
|---|---|---|
| Industrial boilers | 400–900°C | Back-up insulation |
| Furnaces & kilns | 600–1000°C | Secondary insulation |
| Fireproof walls | Ambient–1000°C | Structural fire barrier |
| Marine fire protection | Ambient–800°C | Fireproof panels |
Although calcium silicate board is used in many demanding environments, moisture management is critical.
The board is not waterproof
It can absorb water through its porous structure
Prolonged moisture exposure reduces strength and insulation performance
Therefore, in humid or outdoor applications, proper protection such as cladding, sealing, or vapor barriers is essential.
When selecting a calcium silicate board, consider:
Maximum operating temperature
Mechanical load requirements
Moisture exposure risk
Installation environment
Required service life
Higher-density boards provide better strength and moisture resistance, while standard grades are suitable for controlled indoor environments.
Frequently Asked Questions — Calcium Silicate Board
Highland Refractory supplies two grades: the 650°C grade for standard cement kiln, boiler, and flue duct back-up insulation, and the 1000°C grade for extreme smelting furnace shells, glass tank bottoms, and petrochemical high-temperature vessel insulation. Both grades are 100% asbestos-free.
No. Calcium silicate board is strictly a back-up insulation layer. It cannot withstand direct flame contact, slag erosion, or heavy mechanical impact. The board sits behind the hot-face refractory brick or castable lining to block heat transfer to the outer steel shell.
Boards are easily cut with standard woodworking saws (hand saw or circular saw). No special tools required. Cut boards are dry-fitted behind the hot-face lining and can be secured with refractory mortar, anchors, or mechanical fasteners. Always wear a dust mask during cutting.
Yes. Calcium silicate board is porous and will absorb moisture if exposed to rain or high humidity. Wet boards lose thermal insulation performance until fully dried. Boards must be stored in a dry, covered warehouse on raised pallets and protected from rain throughout shipping and on-site storage.
Standard MOQ is 1 pallet. All boards are made-to-order per project confirmation. Standard thicknesses and dimensions ship faster than custom-cut panels. Contact our sales team with your required grade, thickness, and quantity for a confirmed delivery schedule and factory-direct quotation.
Calcium Silicate Insulation Board is a high-performance, lightweight thermal insulation material designed to provide exceptional fire resistance and superior thermal insulation in high-temperature industrial applications. This non-asbestos product, primarily made from a blend of silica (SiO₂) and calcium (CaO) along with reinforcing fibers, is widely used across multiple industries for its remarkable heat-resistant properties. It is ideal for applications that require continuous exposure to temperatures as high as 1000ºC. This product offers not only excellent insulation but also superior mechanical strength and durability, making it suitable for a wide range of applications, including steel furnaces, chemical processing units, boilers, kilns, and energy systems. Available in various thicknesses and dimensions, calcium silicate insulation boards provide an efficient solution for meeting the challenging demands of high-temperature environments.
Ceramic fiber board is a new type of refractory insulation material.
Highland Refractory® Ultra-thin Ceramic Fiber Blanket is a revolutionary white, uniform fireproof and insulating material that integrates fire resistance, heat insulation, and thermal preservation in one, with zero binders added. Crafted via advanced spinning technology, this High Temperature Ultra-thin Ceramic Fiber Blanket is engineered for extreme heat environments while maintaining an ultra-thin profile (0.5mm-6mm), making it a versatile solution for industrial insulation, thermal protection, and soundproofing applications. As a leading Heat Resistant Ultra-thin Ceramic Fiber Blanket supplier, we prioritize raw material purity, precision manufacturing, and consistent quality—all aligned with ISO 9000 standards and ASTM C795 refractory guidelines. This Fireproof Ultra-thin Ceramic Fiber Blanket stands out for its low density, minimal heat storage, and exceptional thermal stability, solving core pain points like excessive energy consumption, heavy equipment load, and noise pollution in industrial and commercial settings. Below is a comprehensive guide to its technical advantages, applications, and procurement details, designed to meet the needs of global buyers and project engineers.
