11th May 2015
The BSEN 12600 Glass in building - Pendulum test – Impact test method and classification for flat glass, double tyre impact test which has been adopted for a number of years for glazing has now been extended to other cladding materials. It was incorporated into the BS 8298, replacing the soft body impact test BS 8200. However, it was soon noted that the new test method was more onerous on stone, even when the stone sizes and thickness had passed the previous test and shown to be resilient in use.
The Stone Federation asked Sandberg to conduct a series of tests using reliable stones (Jura limestone from Geiger and Jordans Basebed from Albion Stone) to compare the results of the old and new test methods. Szerelmey’s provided the test rig, expertise and labour to complete the installation of the panels of both stones.
During the tests, the impacts were dropped from heights up to 1.02 metres and whilst none of the stones broke, some suffered damage around the fixing points. It was noted that the minor changes to the test methods had a significant effect on the result, such as the tyre pressure. Despite the difference in the flexural strengths between Jura and our Portland Stones, both stones performed very similarly and showed that there is a marked difference between the stresses generated by the different test methods. The tyre impactor test generates higher stress at 200mm than the bag impactor at 1,020mm drop height. Also the bag impactor appears to be non-linear in its behaviour, whereas the tyre impactor is decidedly non-linear.
The Stone Federation will provide some interim guidance on how to interpret and use these results whilst we wait for the rewriting of BS8298, which is due next year. http://www.stonefed.org.uk/index.php?page=contact-us
To find out what impacts are, why they are so important and how they affect you please click on the following download: