Hard Refractories

In many furnace designs, high density refractory bricks are used for hot face and wear zones. Behind that, insulating firebricks (IFB) are the core product: the insulating refractory layer that combines insulation value with a higher temperature grade. Where the design allows additional build up thickness, Insulating bricks can be added as an extra insulation layer to further reduce shell temperature and heat loss. This landing page helps you choose. Detailed information is provided on the relevant follow up pages.

High density refractory bricks

 
For hot face zones with high mechanical or chemical loads, where wear resistance and service life are leading. Dense refractory bricks for complete lining projects. Read more about high density refractory bricks

Insulating firebricks (IFB) up to 1760°C

 IFB are lightweight insulating refractory bricks with a controlled pore structure, designed to insulate efficiently at high temperatures. This is typically the most engineered layer in the wall build up, because low thermal conductivity must be combined with higher temperature grades. Rely on Insulcon engineering support and make an informed choice based on verified performance. Read more about Insulating Firebricks IFB up to 1760°C 

Available according to the ASTM classification for insulating firebricks, classes 23 through 32. The most common industry grades are available from stock as I23, I23C, I26 and I28, with short lead times for I30 and I32 for higher temperature ranges and specific requirements. Dedicated grade for hobby kilns: I24HK.

Insulcon uses the suffix C for casted variants, e.g. I23C stands for ASTM Grade 23 casted, I26C for ASTM Grade 26 casted and I28C for ASTM Grade 28 casted.

Insulating bricks up to 1100°C

For broad use as backup insulation in lower temperature zones, where insulation value and cost efficiency dominate. Read more about Insulating bricks

IFB are produced via three main processes: casting, slinger and extrusion. Each process results in a different pore structure and therefore a different trade off between insulation performance and mechanical properties. Casting focuses on maximum insulation for lower temperature applications. Slinger performs well for insulation in higher temperature zones. Extrusion typically provides the best structural characteristics across the temperature range.

• Low thermal conductivity at process temperature helps reduce heat loss and supports energy efficient insulation concepts
• Lightweight and easy to machine, enabling efficient handling and a neat, repeatable installation
• Tight tolerances and availability as machined shapes reduce cutting work and joints on critical geometries
• Grade and mortar matching supports a consistent build up and predictable behaviour during dry out and in operation

In many furnace designs, an additional insulation layer can be included to further reduce heat loss and shell temperatures, depending on available build up space and construction constraints.

Ferrous – iron and steel
In steel and ferrous processes, the hot face is typically built with refractory bricks in charging, discharging and wear zones with impact and abrasion, complemented by IFB where higher temperature grades and cyclic loads are required. IFB are commonly used as backup insulation in reheat furnaces, heat treatment and annealing furnaces, aimed at lower fuel consumption and faster heat up response. Due to maintenance, thermal cycling and heavy operating conditions, a substantiated and repeatable insulation build up is especially important.

Cement and lime
In cement and lime applications, refractory bricks are often selected for zones with high thermal and mechanical loads. IFB are used where a higher temperature grade must be combined with insulation, supporting an efficient lining build up with controlled shell temperatures and stable thermal performance.

Aluminium and non ferrous
Most furnace build ups combine IFB and refractory bricks. IFB are used as backup insulation in melting and holding furnaces, launder systems and heat treatment furnaces to reduce heat loss and keep shell temperatures manageable, especially under cyclic loads due to heat up and cool down cycles and regular door movement. Refractory bricks are applied in hot face zones with higher mechanical and chemical loads, such as contact with metal, fluxes or slags.

Ceramics – domestic and construction, fireplaces, stoves, pizza ovens
In smaller furnaces such as pizza ovens, forge furnaces and ceramics, you typically see a combination of IFB and refractory bricks. IFB are popular for walls and domes due to easy handling, low weight and good insulation value, also under regular heat up and cool down cycles. For this segment, IFB grade I24HK is often a good fit depending on the target temperature class and design. Refractory bricks are commonly chosen for floors and hot face parts exposed to direct flame and mechanical loads.

Petrochemicals
In petrochemical applications, refractory bricks and IFB are often combined. Refractory bricks form the hot face in critical zones with high thermal load and potential chemical attack, aiming for service life and lining integrity. IFB are applied as the insulating refractory layer behind the hot face materials in process furnaces and heaters, where energy efficiency and stable temperature control are key. Verified performance with test data and documentation on request can be valuable for engineering and inspection.

Glass
In glass processes, refractory bricks are often used in hot face and contact zones where dimensional stability and chemical resistance against glass and vapours are critical. IFB are used where a higher temperature grade and low thermal conductivity must go together, e.g. to reduce heat loss and lower shell temperatures. In continuous operation, the focus is on long term insulation stability and consistent performance.

Energy and waste
In waste to energy and incineration installations, refractory bricks are often chosen for zones with erosion from ash, slag and high gas velocities, requiring a robust hot face. IFB are used where higher temperature grades must be combined with insulation, supporting an efficient lining build up with stable thermal performance, often in and around boilers, ducts, afterburners and heat exchange zones.

Insulcon adds value through zone based selection advice, customization and machined shapes to reduce installation time and unwanted joints. We support the system build up with matching refractory mortars for consistent installation and predictable in service performance.

This supports a lower total cost of ownership through fewer installation hours, less repair work and a more manageable maintenance cycle. By reducing heat loss and material waste, this can also contribute to energy efficiency and a lower CO₂ footprint, depending on furnace design and operating conditions.

Where relevant, we provide European test data and documentation on request per grade and application, enabling engineering and procurement to make an informed selection.

We support selection based on:

• Temperature profile per zone – hot face and cold face
• Process atmosphere – oxidising or reducing, moisture and chemical exposure
• Mechanical loads and required service life
• Geometry and drawing dimensions – machined shapes yes or no
• Existing lining and failure mode, where applicable

IFB are available as standard bricks and as machined shapes, including tapers, arches, curved keys and angle cuts. These non standard shapes help reduce installation time and reduce thermal bridges on critical geometries, for example in skewback details.

Matching refractory mortar is available and aligned to the selected grade, joint width and installation conditions, including dry out advice where needed. This ensures brick, mortar and joint design fit your application and installation method.

We test our IFB grades at independent European test laboratories:
Stazione Sperimentale del Vetro (Italy) - spevetro.it  
ICAR CM2T (France) - icar-cm2t.com   
DIFK Deutsches Institut für Feuerfest und Keramik GmbH (Germany) - annual verification - difk.de 

Test reports are available on request per project or application.

(Logos used for source reference of test laboratories only)

When do I choose IFB instead of Insulating bricks?
Choose insulating firebricks (IFB) when you need stable insulation performance at higher process temperatures, with additional focus on dimensional stability and mechanical stability within the build up. In many industrial furnace designs, IFB are used as the insulating refractory layer, especially where thermal cycling and repeatable installation are important. Typical industries include petrochemicals, ferrous, aluminium and non ferrous, glass, and energy and waste.

Insulating bricks are more often the additional insulation layer when the main goal is to further reduce heat loss and shell temperatures in zones with lower thermal load.

What makes IFB different from standard Insulating bricks?
IFB combine low thermal conductivity with properties required in more demanding zones, such as dimensional stability after firing, better mechanical stability and the availability of machined shapes to reduce cutting work and joints. This is relevant for continuous operation or regular heat up and cool down cycles.

Why choose Insulcon IFB instead of a standard catalogue supplier?
Because you get more than bricks alone. Insulcon combines substantiated quality, European stock availability and engineering support. We help select the right grade per zone and supply machined shapes where needed to reduce cutting work and joints. We can also support a consistent system build up, including matching mortars, so installation is repeatable and in service performance remains predictable. Test reports and documentation are available on request.

When do I choose high density refractory bricks?
Choose refractory bricks where wear, impact, erosion or chemical exposure dominate and the hot face primarily requires robustness. In these zones, insulation value is usually secondary to mechanical strength, wear resistance and chemical resistance. This is common in energy and waste, ferrous, aluminium and non ferrous and in glass contact zones.

Where can I find technical datasheets?
Technical datasheets are available via the product pages and on request. This landing page provides an overview and links to the correct product information per brick category.

What does the C mean in I23C, I26C and I28C?
The suffix C is the Insulcon designation for a casted variant within an ASTM grade. For example, I23C stands for ASTM Grade 23 casted, I26C for ASTM Grade 26 casted and I28C for ASTM Grade 28 casted. We advise per zone which variant, casted or standard, best fits the temperature profile, insulation needs and mechanical loads.