Fire Brick or Refractory Bricks | Types & Features

A fire brick or refractory brick is a ceramic building material in blocks used in construction to withstand high temperatures. The features, properties, and types of fire bricks used in construction projects are explained in this article.

 

Features of Fire Bricks

It was invented by William Weston Young in 1822 in Wales. It is used in kilns, furnaces, and fireplace construction.

Fire bricks gain the property of low thermal conductivity and high energy efficiency. These bricks are used in areas where the structure is exposed to an extreme level of mechanical, thermal, and chemical stresses.

Whatever the temperature condition, the fire bricks are not supposed to spall and the strength expected from them must be equivalent to bear the extreme temperature changes. These are bricks that can be employed for temperatures greater than 1500 degrees Celsius.

                      

Read More On : Fire Resistance of Concrete

 

Manufacture Fire bricks

Fire bricks are made from materials belonging to four main classes. They are:

1. Fire-clay
2. Rocks with pure silica
3. Ganister (Rocks with silica as major content and 10% clay)
4. Chromite, magnesia, and alumina ( Neutral and basic materials)

During the manufacture of fire bricks, fire clay is fired in the kiln. The process is continued until the fire clay becomes vitrified. For special cases, the process continues until glazing is obtained. The standard sizes of fire bricks are:

1.229 x 114 x 76 mm
2. 229 x 114 x 64 mm
3. 229 x 114 x 32 mm – fire brick splits

Characteristics of Fire bricks

The chief characteristics of fire bricks are:

1. High-temperature resistance
2. Resistance to sudden temperature changes
3. Resistance to pressure at higher temperatures
4. Negligible or no expansion during higher temperatures
5. Resistance to wear and tear
6. Resistance to reduction or oxidation reaction
7. Resistance to accidental blows
8. High resistance to abrasion by dust, metal, slag, and other materials
9. Low absorption property at high temperatures
10. Possess uniformity in size, shape, and composition

Fire Clay bricks are the most manufactured type of fire bricks. The important constituents of fire clay bricks are mullite and silica and a glassy matrix. Free alumina, calcium, unaltered quartz and other types of silica are also present in minor quantities.

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