The top layer on a safety flooring is the wear and tear layer. Is the one suffering the heavy use, the big temperature changes, the effects of UV, rain and snow, the indentation from long heels, the mischief of some children, the effect of different pollution materials as leaves, detritus from animals, sand and rests of food, garbage and I don’t know how many other things.
Materials to be used for a top layer flooring, must be then carefully selected and tested to ensure they allow a long useful life of the area.
As materials suppliers, when we want to introduce a new material we have a long list of standards that define procedures for ageing, weathering and methods for testing wear and tear that are able to simulate years on real life. We can also test colour stability to UV, water permeability, flammability and any other kind of requirement. Is not easy to find a precise relationship within the simulated test and the equivalent in real time, but you can at least have a good reference and then decide if you can assume or not the risk of warranty claims.
I you want to know if cork is a good material for top layer, better you end up your reading here and go to do another more interesting thing because I have no idea. I don’t have experience with this material nor seen enough evidences of test results to give you any advise. Ask me again in one or two years and maybe I can be more helpful.
For the moment, for me cork is the last obstacle to access my best bottles of Rioja wine or Catalan Cava. One of my funny and clever colleagues is probably in the same situation as me. He told us he would be glad to supply cork raw material as he had a couple of bottles of Chardonnay that would not last long and offered to open them for the purpose of flooring science.
I like natural materials, but unfortunately, some functional requirements very frequently are only achievable with synthetic solutions.
Now I can talk about something I know. Should I use TPV or EPDM?
TPV – Vulcanized Thermoplastics – Elastomer formable as temperature increases.
EPDM – Ethylene, propylene, diene, monomer – Thermally stable elastomer with good resistance to abrasion and wear.
Both types of granules are used as a top layer in safety surfacing for playgrounds and multi-sport areas and as in-fill on artificial grass sport pitches.
TPV is permanently elastic within a wide temperature range although a bit smaller than EPDM. The elasticity is usually lower than that of EPDM.
The suitable TPV granules can have similar basic properties as EPDM granules. Due to the lower cross-linking of polymer chains, they may have limited performance at higher environmental temperatures. At lower temperatures the reversible hardening is greater than that of EPDM granules.
From the installer point of view, to get a nice visual finish is tougher to achieve with TPV than with EPDM, since TPV granules are a bit harder than EPDM. Installer must push a lot more with the trowel to get the good finish and it takes a bit longer time per m2.
You can notice that elasticity is better on EPDM. This does not mean a big difference on the Critical Fall Height achieved, as top layer has a minor influence.
The price level of TPV has been usually a bit higher than EPDM, although you can find some TPV manufacturers with cheaper prices.
One area where TPV is better than EPDM is on UV colour stability. TPV granules respond very well to UV weathering what makes them the preferred choice on areas with very high UV levels.
CONCLUSIONS:
The mechanical properties of EPDM are better than those of TPV, specially elasticity, strength and compression. Colour granules heat up significantly in solar radiation, so TPV granules will be more influenced on the mechanical properties than EPDM on outdoor applications.
If UV level is very high and the surface design is using certain vivid colours that we want very stable, TPV would be a better option.
I think that EPDM will continue to be the most reliable option for safety surfacing applications with a balance of properties and price that remain unmatched.
If you don’t agree I can call my friend, and as soon as international travels are allowed again after COVID-19, we can meet face to face and open a technical discussion about it while also opening one of his Chardonnays or my Cava for a rigorous test of the cork.
Take care
Rubberman Blog 