Calcium silicate board (CaSi board) is a widely used insulation and refractory material in industries such as steel, cement, glass, and petrochemicals. Known for its low thermal conductivity, high strength, and asbestos-free eco-friendly composition, it provides reliable insulation for high-temperature applications.
However, like any material, calcium silicate board is not without its limitations. Understanding the disadvantages of CaSi boards helps users make informed decisions and select the right insulation for specific applications.
Although calcium silicate boards offer excellent compressive and flexural strength, they are inherently brittle. They may break or chip under mechanical impact, so extra care is required during transportation, cutting, and installation.
Most commercial CaSi boards are rated for 1000°C or 1100°C. While this covers many industrial applications, it is lower than ceramic fiber boards (1260–1600°C). Long-term exposure near the maximum service temperature can result in shrinkage and dimensional changes.
Calcium silicate boards can absorb up to four times their dry weight in water. In humid environments, absorbed moisture reduces strength and may cause cracking during heating if not dried properly. Waterproof-treated boards are recommended for moisture-prone applications.
Cutting and drilling CaSi boards produce fine dust particles. Although asbestos-free, prolonged exposure to dust may pose health risks, so protective equipment is necessary during installation.
Compared to traditional insulating fire bricks, calcium silicate boards are more expensive. The hydrothermal xonotlite production process and fiber reinforcement add to the cost.
Even though CaSi boards are dimensionally stable, they still show 1.5–2% shrinkage when exposed to high temperatures for long periods. This may lead to gaps in insulation lining systems if not properly accounted for.
CaSi boards can crack under rapid heating and cooling cycles, especially compared to ceramic fiber modules. Fiber-reinforced grades perform better, but thermal cycling remains a limitation.
| Property | Calcium Silicate Board | Ceramic Fiber Board | Insulating Fire Brick (IFB) |
|---|---|---|---|
| Max Temp. | 1000–1100°C | 1260–1600°C | 1050–1400°C |
| Strength | High compressive & flexural | Low, flexible | Moderate |
| Thermal Conductivity | Low (0.06–0.22 W/m·K) | Very low | Moderate |
| Brittleness | Brittle | Flexible | Less brittle |
| Water Absorption | High | Low | Low |
| Cost | Medium–High | High | Low–Medium |
Even though calcium silicate board (CaSi) has several drawbacks, many of them can be effectively managed through proper selection, design, and application. Here are some practical strategies:
Calcium silicate board is a highly efficient insulation material that balances strength, low thermal conductivity, and eco-friendliness. Yet, its brittleness, moisture sensitivity, and limited temperature range mean it cannot fully replace other refractories in every case.
At Zhengzhou Firebird New Material Co., Ltd., we provide calcium silicate boards in 1000°C & 1100°C grades, reinforced with glass or carbon fibers, and available with waterproof treatments. With over 20 years of expertise and CNC machining capabilities, we deliver customized refractory solutions tailored to your needs.
Contact us today to request a free sample and explore how calcium silicate board can improve your insulation systems.
Yes. It can absorb up to four times its dry weight in water. Waterproof-treated boards are recommended for humid environments.
It is brittle and may crack under impact or rapid thermal cycling. Fiber-reinforced grades are more resistant.
Yes, it has higher compressive and flexural strength, but it is also more brittle.
Depending on grade, calcium silicate boards can withstand up to 1000–1100°C.
Yes. It is asbestos-free and eco-friendly, though dust during processing requires protective equipment.
Standard grades are not recommended. Special carbon fiber-reinforced high-density CaSi boards are suitable for aluminum applications.
