Insulating firebricks, also known as IFB, combine low thermal conductivity with a higher temperature class for furnaces and process equipment. They are typically used as an insulating refractory layer behind hot face materials, where energy efficiency and controlled outer shell temperatures matter, without compromising dimensional stability and installation quality. We supply standard bricks and CNC machined shapes, including matching mortars and engineering support per zone.
Independently tested in Europe, verified performance
Tested at SSV (Italy), ICAR (France) and DIFK (Germany), with annual verification.
Test reports are available on request per project or application
Our IFB are available in accordance with the ASTM classification for insulating firebricks, classes 23 through 32. Commonly used grades include I23, I23C, I26 and I28, with options up to I30 and I32 for higher temperature ranges and specific requirements.
Insulcon uses the suffix C for cast variants. For example, I23C means ASTM Grade 23, cast. I26C means ASTM Grade 26, cast, and I28C means ASTM Grade 28, cast.
We support your grade selection based on:
Request the datasheet for each grade and, where relevant, the project documentation. Key comparison parameters include density, compressive strength, dimensional stability after heating, linear shrinkage, thermal conductivity at process temperature and behavior under thermal cycling. We provide these data on request per application, so the selection can be justified towards design, HSE and maintenance.
IFB are produced via three main processes, casting, slinger and extrusion. Each process results in a different pore structure and therefore a different balance between insulation performance and mechanical properties.
In practical terms, casting is often chosen when maximum insulation is required at lower mechanical loads, slinger when a favorable balance between insulation and a higher temperature class is needed, and extrusion when structural characteristics and repeatable geometry are leading.
IFB are available as standard bricks and as CNC machined shapes. Common shapes include tapers, arches, curved keys and angle cuts. This reduces the number of critical joints, shortens installation time and reduces thermal bridges in details such as skewbacks and arch transitions.
An insulating refractory IFB layer performs consistently only when brick, mortar and joint width are matched. We supply compatible refractory mortars and advise on joint width, water dosage, working time and storage conditions. Where required, we also provide dry out guidance, aligned with the full lining build up and the heat up regime.
IFB up to 1760°C are used in industrial furnace constructions where insulation performance at high temperature is required, with attention to service life and installation quality. Examples include reheat and heat treatment furnaces, non ferrous melting and holding furnaces, process furnaces and heaters, glass and ceramic installations, and energy and waste facilities where outer wall temperatures and energy losses must remain controlled.
We have IFB grades tested at independent European test laboratories, including Stazione Sperimentale del Vetro (Italy), ICAR CM2T (France) and DIFK Deutsches Institut für Feuerfest und Keramik GmbH (Germany), with annual verification where relevant. Test reports are available on request per project or application.
Download IFB overview leaflet, overview of available grades and key specifications.
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What is the difference between IFB and insulating bricks?
IFB are designed for higher temperature classes with additional focus on dimensional stability and mechanical stability. Insulating bricks are more often used as an additional back up layer in lower temperature zones, where insulation value and cost efficiency dominate.
When do I choose a cast variant with suffix C?
Cast variants can be attractive when insulation is the main priority and the application fits within the mechanical boundary conditions. We advise per zone whether a cast variant or another execution is the best match for load, temperature and installation details.
Can I combine IFB with dense refractory and mortar from another supplier?
Technically it is possible, but the biggest gain in predictability comes from a matched system build up. Therefore we recommend assessing grade, mortar and joint design together, including the dry out procedure. This reduces failure risk and speeds up troubleshooting during maintenance.
Looking for advice? We will help you to find a suitable solution! Give us your details and we will contact you as soon as possible.
