Insulating Firebrick

Insulating Firebricks

BNZ produces thirteen types of Insulating FireBrick (IFB) for use in applications from 2,000°F (1,093°C) to 3,200°F (1,760°C). Each type is formulated to meet specific thermal and physical requirements and after firing is machined to precise tolerances.
Made from high purity refractory clays and other ceramic raw materials, these IFB contain a carefully graded organic filler which is burned out during manufacture to give a uniform controlled pore structure.

BNZ Materials manufactures, and is a worldwide supplier of a range of specialty industrial insulations and refractories for petrochemical, electrical, aluminum, steel, ovens, glass, furnace, ceramics, fire protection and other industries.

BNZ Standard ASTM Grade

BNZ Specialty Grade

Plemet France IFB Grades

The PA Series of insulating fire brick (IFB) adds a lower cost alternative to BNZ’s traditional line of IFB. The PA series is designed for applications where the lower density and finer texture of the standard BNZ grades is not required. They meet or exceed the specifications of ASTM C 155 for each listed grade, and are produced under BNZ’s certified ISO 9001 Quality System.
Plemet France Grades

Additional Insulating Fire Brick

Advantages of IFB

High Insulating Value. The light weight and high insulating value of BNZ IFB make possible thinner furnace walls, improved efficiency and lower operating

Strong. The high compressive strength of IFB allows for self-supporting structures at elevated temperatures. IFB are compatible with dense fire brick, and add strength to the whole construction.

Low Heat Storage. Lower heat storage versus dense brick means reduced fuel costs and faster heat-ups in cyclically operated heating equipment.

High Purity. BNZ IFB are low in impurities such as iron, which can adversely affect refractory performance in many applications. They are used in many furnaces with controlled atmospheres.

Accurate Dimensions. Because BNZ Insulating Fire Brick are machined to precise dimensions, courses can be laid quickly and easily, and the result is a stronger, tighter refractory lining resulting in less heat loss through the joints.

Typical Applications

Recommended for use as primary hot face refractory linings or as back-up insulation behind other refractories in furnaces, flues, kilns and similar high temperature
industrial equipment.

Size is no Obstacle

Most BNZ IFB are available in Zelie Jumbo™ series, which require no mortar joints to produce sizes up to 24″ x 9″ x 3″. No longer are there design limitations caused by traditional standard brick shapes and sizes. The nominal cost of Zelie Jumbo sizes is more than offset by the elimination of many mortar joints and significant labor savings.


Available Forms

In addition to the great number of standard sizes available, Insulating Fire Brick are also available in special cemented or machined shapes. A large
machine shop at the factory is capable of supplying accurate machined shapes of nearly any description. The unique large slab means that a finished shape
will have fewer joints than shapes made from any other IFB manufacturer.

IFB shapes with drilled holes, grooves, flycuts, tapers, radii cuts, skew planes, tongue and groove, notches
and chord cuts are easily fabricated in any quality IFB.

Thicknesses up to 41⁄2,” along with widths up to 12,” allow a range of shapes and sizes for applications such
as suspended roof modules.


Temperature use limits should be considered along with other properties of the IFB in determining the proper
grade to use for your application. The hot load deformation along with the mean temperature (i.e. the temperature at the midpoint of the brick) should be considered as well, to assure a successful application.
Guidelines for the mean temperature of each type brick are:

1800°F (982°C)
2100°F (1149°C)
2200°F (1204°C)

2400°F (1316°C)
2600°F (1427°C)

BNZ-23, BNZ-23HS, 23A, C-22Z
BNZ-25, BNZ-26,
BNZ-26-60, BNZ 26-HS
Consult your BNZ representative for recommendations on the best combination of products for your temperature, processing and atmospheric conditions.

Complementary Mortars

BNZ manufactures a range of specially-formulated mortars with the proper water retention characteristics
that makes them uniquely suited for laying porous IFB. Consult your local BNZ representative for the proper mortar for your application.

BNZ Standard ASTM Grades

BNZ-20 has the low density to meet the criterion for ASTM Grade 20. Its low reheat shrinkage meets the ASTM Grade 23 criterion.

BNZ-23 is the traditional 2300° IFB manufactured by BNZ. It has a history for excellent service in suspended arch designs under cycling conditions.

BNZ-23 HS is a high strength ASTM 23 Grade for applications where a stronger brick than the traditional 23 is required.

BNZ-23 A is a slightly lower density, higher strength version of the BNZ 2300 IFB which can be used in any application where a lower density IFB may be needed.

BNZ-26 is the standard ASTM Grade 26.

BNZ-26-60 meets all requirements of an ASTM C 155 class 26 IFB, with a higher alumina content than the standard BNZ-26 IFB. This makes the BNZ- 26-60 specially designed for areas where furnace atmospheres require the chemical inertness of a higher alumina product. These include the exposed lining of ceramic kilns and special atmosphere furnaces.

BNZ-28 is the traditional ASTM Grade 28.

BNZ-3000 has long been the standard for true ASTM Grade 30 brick. Its low reheat shrinkage at testing temperature of 2950°F is an indication of its ability to
tolerate excursions above normal operating temperatures in applications such as strip annealing furnaces.

BNZ-32 is a reasonably priced alternative to bubble alumina brick in many high temperature applications or where high alumina content is required. The Zelie Jumbo sizes are especially useful as spanner brick over burner tile.

BNZ Specialty Grades

C-22Z is a higher strength IFB for applications
to 2300°F. It is normally specified in load bearing applications.

BNZ-25 has been improved with higher strength. Its 2500°F rating fills the gap above 2300°F without the cost of high temperature brick.

BNZ-26 HS is a new designation of the former BNZ-1400. It has a combination of very high strength and superior thermal shock resistance. Typical applications
include steel ladle and tundish back-up insulation, wear areas of ceramic kilns, carbon baking anode furnaces
and high traffic areas in a variety of furnaces and kilns. This grade also replaces the YUMA brick. YUMA brick
can still be made to order on special request.

The physical and chemical properties of BNZ’s Insulating Fire Brick represent values obtained in accordance with accepted test methods and are subject to normal manufacturing variations. They are supplied as a technical service and are subject to change without notice. Results should not be used for specification purposes.