Quality of Bricks

Bricks should be uniform in color, size and shape. Standard size of brick should be maintained.

They should be sound and compact. They should be free from cracks and other flaws such as air bubbles, stone nodules etc. with sharp and square edges.

Bricks should not absorb more than 1/5 of their own weight of water when immersed in water for 24 hours (15% to 20% of dry weight).

The compressive strength of bricks should be in range of 2000 to 5000 psi (15 to 35 MPa).

Salt attack hampers the durability of brick. The presence of excess soluble salts in brick also causes efflorescence. The percentage of soluble salts (sulphates of calcium, magnesium, sodium and potassium) should not exceed 2.5% in brunt bricks.

Brick should not change in volume when wetted. Bricks should neither overburnt nor underbrunt.

Generally, the weight per brick should be 6 lbs. and the unit weight should be less than 125 lbs. per cubic ft.

The thermal conductivity of bricks should be low as it is desirable that the building built with them should be cool in summer and warm in winter.

Bricks should be sound proof. Bricks should be non-inflammable.