Shell Gris Abrasion Testing Big Commercial Stone Project
November 25th, 2011 in Case Studies, Technical Data
This week I had to confirm the suitability of our Shell Gris for a very large commercial project I am currently working on. The building in The City would be the workplace for over 6000 people and with the design life of 50 years. This requirement would mean the stone needs to withstand 150,000,000 visitors during its life (6000 x 2 (to and from work) x 250 (working days in the year x 50 (design life). If you add the fact that everyone might go out for lunch and that then doubles to 300,000,000!! But that would be taking it too far detail wise!
We use the abrasion test BS EN 14157 2004 to establish the suitability of any given stone. I popped down to the lab (Sandberg Consultancy – Clapham www.sandberg.co.uk ) to watch these taking place being the nerd I am. The stone samples are first dried (really dried) and then using a marker the consultant marks the surface before fixing in place. A spinning wheel is pressed against the stone surface at a given pressure and then an abrasive poured into a funel from above falls between the two surfaces. This continues for 1 minute exactly then the stone is removed and the width of abrasion created is measured. The measurment recorded (in millimetres) and this is repeated in this case for six specimens (the recommended number of samples). Interestingly we used 3no polished and 3no honed and it made very little difference, just 0.5mm. A difference all the same.
The result recorded for our Shell Gris was 19.50. This is an excellent result and means the stone can resist 500,000,000 foot traffickings during its life so in fact we can allow the people using the building to nip out for lunch and half of them to pop out for a fag break too.