Home > Start > Contents > Testing metamorphic slates
Testing metamorphic roofing slates

Testing stone slates

In July 2004 a European standard for roofing slates was published - BS EN 12326-1: 2004 Slate and stone products for discontinuous roofing - Part 1 Product specification. This standard replaces all previous standards throughout Europe including BS680 Roofing slates. 
The product specification is mainly established against a series of tests described in BS EN 12326-2: 2000 + A1 Slate and stone products for discontinuous roofing - Part 2 Methods of test. The A1 indicates that it includes amendments dated July 2004. 
Any manufacturer claiming conformity with the product specification must carry out the tests (relevant to their product) described in Part 2 and make the results available in a prescribed format (Acrobat file). This report (the official terminology is 'accompanying commercial document' ACD) is in two parts. The first part includes information about the manufacturer (producer), the slate source and the testing together with the test results. The second part explains the meaning of the tests and what is required for conformity to the standard. It is included because some of the tests have different levels of conformity (indicated by a code: S1, T3 etc) and others have varying requirements depending on the fundamental properties of the product. One example of the latter is the minimum thickness of the slates in relation to the strength of the slate rock from which they are made. It is included to help specifiers and purchasers to understand what they need from a slate and to ensure they get it. The ACD is not complete without both parts. 
Because the standard contains several different levels of conformity which relate to the different durabilities acceptable in different countries and methods of slating, contractual specifications for roofing slates will need to be more sophisticated than in the past. It is no longer sufficient to specify ‘slates which conform to the relevant British Standard’ or even ‘slates which conform to BSEN12326-1’. Such blanket specifications would allow slates to be supplied at the lowest conformity level within the standard and this could mean a life of perhaps only 40 years. 
Strictly, a manufacturer claiming conformity to the standard should supply a copy of the ACD with every consignment. However it seems to me to be reasonable that they should make copies available on their website. They will, of course, need to include a separate copy of the first part (the test results etc) for each product because they will have different properties such as thickness.
For a full understanding of the product specification and the test methods you should read the standards. Copies are available from national standards organisations. In the UK contact BSI or their agents. On the BSI website search for 12326-1 or -2