The term ‘special quality’ comprises bricks that are durable even when used in conditions of extreme exposure where the structure may be saturated. This makes such bricks ideal in retaining walls, below DPC level, below ground, inspection chambers, copings to the top of walls, DPCs (when in solid form), and so on. Engineering bricks usually attain this level of quality as do some facing bricks. It must be remembered that, because many engineering bricks are smooth-faced, they can also be simultaneously classified as commons – on this basis it could also be argued that many commons achieve a quality defined as ‘special’.
The remaining two levels of quality are more a measure of the appearance, colour and shape of a brick as opposed to durability and performance.
Bricks that have become deformed and/or mis-coloured during manufacture are known as ‘seconds’ and are frequently sold at a lower price than the ‘perfect’ equivalent. Seconds are unlikely to be used for facing work and certainly not for facing work of high quality.
On ‘selected’ bricks the quality falls somewhere between ‘perfect’ and ‘second’ – for example, the brick may suffer from minor discoloration only. The term ‘selected’ is quite subjective and usually used at the discretion of the supplier.