1. What it means
So, what does planarity mean? The word planarity is rooted in the Latin word plānus, which means flat, and the late Latin word plānāris, which means to be on level ground. When we speak about planarity, it is usually in reference to the flatness of a playing surface.
2. How to measure it
The proper way to measure the planarity of a surface begins with a 3.0m straight edge beam comprised of box section aluminium with a specified weight and size. After calibrating, this tool is then dragged by a test engineer across the surface, as seen in the featured photo above. Whenever a bump or dip is observed, a calibrated and graduated wedge is placed in the gap between the straight edge beam and the surface where the irregularity is measured to a 1mm accuracy.
3. The tolerances
With football and baseball being two known exceptions, Global Governing Bodies have placed stringent requirements on the planarity of fields.
Soccer - A maximum of 10mm gap between beam and surface
Rugby - A maximum of 10mm gap between beam and surface
Field Hockey - A maximum of 6mm gap between beam and surface
Basketball - A maximum of 6mm gap between beam and surface
4. Why it needs to be tested
Testing the planarity of a surface is the best-known way to assess whether or not a base has been properly compacted and this is the main reason contractors use it. It's critical to ensure that the construction of any base has been carried out to the strictest tolerances. It is especially important to do a planarity test on any sub-contractor work. Test Institutes use planarity tests in a similar fashion to determine compliance with governing body requirements.
5. Planarity tests are an evolving technology
Although planarity tests have been around for a long time, there is a lot of excitement with new advances in the technology used to improve the tests. Sports Labs is currently working to introduce an innovative, automated design which will not only improve the precision of detecting abnormalities on a surface but also enable the ability to log their magnitude as well.
Eric O'Donnell, Managing Director