Qualities of Good Bricks

The good bricks which are to be used for the construction of important structures should posses the following qualities;

1. The bricks should be table-moulded, well burnt in kilns, copper-coloured, free from cracks and with sharp and square edges. The colour should be uniform and bright.
2. The bricks should be uniform in shape and should be of standard size.
3. The bricks should give a clear metallic ringing sound when struck with each other.
4. The bricks when broken or fractured should show a bright homogeneous and uniform compact structure free from voids.
5. The brick should not absorbs water more than 20% by weight, for first class bricks and 22% by weight for second class bricks, when soaked in water for a period of 24 hours.
6. The bricks should be sufficiently hard. No impression should be left on brick surface, when it is scratched with finger nail.
7. The bricks should not break into pieces when dropped flat on hard ground from a height of about one meter.
8. The bricks should have low thermal conductivity and they should be sound proof.
9. The bricks, when soaked in water for 24 hours, should not show deposits of white salt when allowed to dry in shade.
10. No bricks should have the crushing strength below 5.50 N/mm².