GRADING / CLASSIFICATION OF TILES

FIRST GRADE

Applicable to ceramics and porcelain this must conform to E.N. specifications (European Norms, which combine the German DIN standards, British BS standards and French UPEC standards). These standards govern the parameters of water absorption, size variation tolerances, measure of hardness, scale and resistance to thermal shock, crazing and chemical attack, abrasion levels and frost resistance.

COMMERCIAL GRADE

Is often referred to as “Run of the Kiln” This normally comprises 75-80% first grade product and 20-25% second grade product (mixed in the same box), the latter having some defects or off-standard quality problems, such as size variation beyond the 0.5% in which case the grouting joints will need to be slightly wider. The hardness of glaze is exactly as per first grade product as production processes are identical. Only when sorting the tiles one will find some visible defects or blemishes. Commercial grades/ROK’s are sold with a 15-20% cost saving. This cost saving is in lieu of labour having to separate the firsts from the seconds from the production run. A manufacturer knows that from production to production they produce a certain percentage first grade, say 75%, then 20% seconds and 5% thirds/rejects. The rejects are discarded and he is left with approx. 80% firsts and 20% seconds as a mix in one box. Commercial grade is not to be confused with Commercial Applications/Areas. It is strictly a quality term in this instance.

SECOND GRADE

When the manufacturer separates the firsts out of the production run from the second grade (out of spec) and boxes the latter separately. Various criteria combine to make up second grades: The specifications fall outside the parameters set by European Norms, e.g. sizing variation may be greater than the 0.5% allowed, the shading/tonality vary from the intended colour mix. There may be small blemishes, pinholes or glazing defects or combinations thereof (patent defects).

The glaze hardness should however be the same as per first grade as the production/firing process the tiles undergo are identical. Cost savings are between 20%-30%.

THIRD GRADE or REJECTS

Defects here are much more pronounced than in second grade. Tiles may be chipped (pieces missing) with visible shrinkage cracks and more obvious blemishes and glazing defects. Thirds are sold at roughly at half the price of firsts.

No manufacturer will guarantee anything other than First Grade product. Customers must familiarize themselves with the possible problems attached to purchasing Commercial, Second or Third Grade. No claims will be entertained on anything other than First Grade products