To avoid confusion and to standardize, the following terminology was introduced and is currently used by the industry.
FBS - FACE BRICK STANDARD
Clay bricks that are selected or produced for their durability and uniformity of size and shape.
NFP - NON-FACING PLASTERED
Clay bricks suitable for general building work that is to be plastered
FBX - FACE BRICK EXTRA
Clay bricks that are selected or produced for their durability and high degree of uniformity of size, shape and colour
NFX - NON-FACING EXTRA
Clay bricks suitable for use, plastered or unplastered, for general building work where durability rather than aesthetics is the key selection criteria: below damp-proof course or under damp conditions or below ground level
FBA - FACE BRICK AESTHETIC
Clay bricks that are selected or produced for their durability and aesthetic effect deriving from non-uniformity of size, shape or colour.
...E - ENGINEERING UNITS
Masonry units produced for structural or load-bearing purposes in face or non-face work, where the manufacturer suppliers clay bricks to an agreed compressive strength. An engineering unit is...