It can be hard to keep up with all the standards for building products, especially as they frequently change. In this column, Barry Hunt throws some light on the standards, identifying those you need and those you don’t. This time he looks at BS EN 1342 – Setts or Natural Stone for External Paving.

BS EN 1342 – Setts of Natural Stone for External Paving has recently been updated and, if you are still relying on the old version, you must think again because there are substantial changes in the updated version, many of them potentially critical.

The standard is currently £162 through the British Standards Institution – and my usual gripes apply. It is a high price for what is a 34-page document that has 16 pages of standard text, titles and other information, leaving the true cost at close to £10 a page for the material you actually need.

The updated standard has now caught up with more recently published natural stone standards.

Basically, when the original standard was published, some of today’s tests did not exist, so methods for determining the dimensions, abrasion resistance and slip resistance were included in annexes, which have now been removed. There is also a considerable amount of information on sampling. It runs to three pages when previously it was contained in a single paragraph.

Looking through the main text of the updated standard, there are a few additions and subtractions to the definitions, the most important being that the shape and size of setts has been re-classified, while the minimum dimension has been reduced from 50mm to 40mm.

This is a simple change but a very small piece of good news for the green lobby and quarry operators as it represents the potential for reduced quarry wastage. The tolerances for the sizes have been completely re-vamped and are reasonably clear and concise.

The sections dealing with testing are no longer vague. They state clearly which tests must be carried out.

Thankfully, freeze-thaw testing can no longer be fudged by not declaring a value.

The number of frost cycles required has also changed from 48 to 56, which is in keeping with the current freeze-thaw test standard.

There is also a short section on the use of de-icing salts, although the problem here is that there is no accepted method for testing natural stone setts to determine their resistance to such materials.

In a similar vein, there are short sections on skid resistance and durability of the slip and / or skid resistance, for which there are no widely accepted test methods.

The Annexes now include the standard blurb regarding conformity and CE marking that all the other more recent or updated older standards have, so the standard is now in step and no longer an old fossil.

This is a good standard but I cannot say that it is good value for money. On my arbitrary scale, it rates at about 37%. But if you are dealing with setts, you simply cannot do without it.

References:

BS EN 1342:2012. Setts of natural stone for external paving – Requirements and test methods. Published by the British Standards Institution, London, England.

Barry Hunt is a Chartered Geologist and Chartered Surveyor who has spent 20 years investigating issues relating to natural stone and other construction materials. He now runs IBIS, an independent geomaterials consultancy undertaking commissions worldwide to provide consultancy, inspection and testing advice. Tel: 020 8518 864.