Insulating firebrick

Includes regular fireclay, semisilica superduty fireclay, ladle brick, and insulating firebrick (IFB) below 23. Includes high alumina, mulhte, and extra high alumina brick. 

Insulating Brick ASTM classifies insulating firebrick under C155 by group. The group number corresponds to the service temperature divided by 100 (Table 13). For example, group 16 corresponds to a test temperature of ca 1600°F (871°C). 

Tne insulating firebrick is a class of brick that consists of a highly porous fire clay or kaolin. Such bricks are light in weight (about one-half to one-sixth of the weight of fireclay), low in thermal conductivity, and yet sufficiently resistant to temperature to be used successbilly on... 

Figure 17-3 shows a steel vessel lined with block under insulating firebrick and acid brick. At high operating temperatures, a proper brick thickness reduces the temperature on the block to 800°F or below. The maximum temperature limit for the block under brickwork or any other organic lining is 800°F. This limit, lower than the 960°F for the block alone, is necessary because the load placed on the block by another lining material may cause the block to creep and distort at temperatures above 800°F. 

Another important thermal property dealt with in Sec. 13.6 is thermal conductivity. It is the low thermal conductivity of ceramics, together with their chemical inertness and oxidation resistance, that renders them as a class of materials uniquely qualified to play an extremely demanding and critical role during metal smelting and refining. Many ceramics such as diaspore, alumina, fosterite, and periclase are used for the fabrication of high-temperature insulative firebrick without which the refining of some metals would be impossible. 

It is this latter approach that is used in fabricating insulating firebricks for furnaces and kilns. The bricks are fabricated so as to be porous and contain many flaws. Because of the very large number of flaws and pores within them, the bricks can withstand severe thermal cycles without structural failure. 

Fig. 9-11. Thermal conductivity data of high-temperature materials (o) refractory brick and (6) insulating firebrick. Courtesy of C. L, NorUm, Jr., Chem. Eng., 60(6) 216 (1953).]...

Table 9-7B, Characteristics op High-tbmperatuhb Insulation. Classification op Insulating Firebrick...

Firebrick was the dominant furnace material from about 5000 bc to the 1950s. Many years ago, man discovered that tufa (calcareous sinter, or solidified bubbled lava) is an excellent insulating material for high-temperature furnaces (maybe as in this book s frontispiece). Modern insulating firebrick is a manmade equivalent of tufa. 

Insulating firebrick (kaolin) with many very small air pockets is a modem replacement for tufa. 

ASTM 0134-95(1999), Standard Test Methods for Size, Dimensional Measurements, and Bulk Density of Refractory Brick and Insulating Firebrick, 1999. 

ASTM C-93 Cold crushing strength and modulus of rupture of insulating firebrick... 

ASTM C-134 Size and bulk density of refractory brick and insulating firebrick... 

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