EN 12326 - Dimensions and dimensional variation

Thickness

The producer has to state the nominal thickness of every slate product as well as the percentage variation of the single thickness of slate slabs in respect to the nominal thickness. The single thickness slate slabs has to be at least 2 mm.

Depending on the bend strength, climatic conditions and the traditional technics of the different countries, the minimum single thickness of slate slabs has to be determined and, if necessary, increased. One hereby dinstinguishes slates with a carbonate content ≤ 20 % from slates with a carbonate content ≥ 20 %. The following tables gives an overview about the adjustment of the thickness.

* Resistance to sulphuric acid

If slates with a carbonate content of 20 % or above corresponds to the coding S3, then they have to have a minimum single thickness of 8 mm or a thickness according to the following formula:

minimum single thickness =
basic single tickness + 0,5 + [7 x (thickness of the softening zone²)]

In addition, the packed thickness of 100 slate shingles has to be determined, whereas the thickness can only differ ± 15 % of the nominal thickness.

Variation in length and width

Rectangular slates can differ ± 5 mm from the length and width stated by the dealer.

Variation of the straightness of the edges

The requirements are valid for the edges of rectangular slates with the following limits:

• for slate slabs with a length ≤ 500 mm the variation can not exceed 5 mm.

• for slate slabs with a length > 500 mm the variation can not exceed 1 % of the length.

Variation of the rectangularity

The max. variation of the rectangularity of slate slabs has to be below the normative value of ± 1 % of the length.

Variation of the evenness