Answer by Rakshita Nagayach:
The advantages of Porotherm Thermo bricks are plenty and are as follows:
- These bricks have a very small value of rate of heat loss (generally called as U-value), nearly 0.6 W/m²K whereas that for a solid clay brick and a solid concrete block is 1.8 W/m²K and 2.0 W/m²K respectively. The U-value must be as low as possible as then less energy is required for cooling or heating the indoors of a building.
- These are noteworthy Energy savers as they eliminate the need of external insulation such as cavity walls and thus save spaces. Also the need for air-conditioners in summers and heaters in winters is decreased.
- These bricks have already been burnt (at 1000 degree Celsius) and are thus immune to fire. They just get baked in case of fire, without releasing any toxic gases or harmful vapours. They have high fire ratings which means there is pretty good amount of time to evacuate the building in case of fire before damage occurs.
- They are 60% lighter than the conventional clay/concrete bricks and thus are easy to handle. This leads to lesser dead load as well as increase in speed of construction.
The few disadvantages are:
- The compressive strength of Porotherm Thermo bricks is slightly above 3.5 N/mm² whereas that of Class I clay bricks is 7 N/mm² (Based on British Standard 3921:1965). This restricts the use of Thermo bricks in huge structures.
- The water absorption is about 15% in case of Porotherm Thermo bricks whereas it is generally preferred to be 10% in clay bricks as more absorption leads to salt attacks and thus reduces the strength of the structure.
- These bricks have a density of approx. 694 to 783 kg/m^3 which is pretty less than that of clay bricks (which ranges from 1400kg/m^3 to 2100 kg/m^3). Thus the Porotherm bricks cannot be used, specially for foundation and base-slab works in areas of high round water table as they would not be able to resist the negative pressure of water and capillary action.
Here’s how Porotherm Thermo bricks are used:
Image source: Google Images