The Australian Standard 1428.4:2009 (Appendix E) requires the installed TGSi to possess a certain percentage of luminance contrast between the amount of light reflected from the surface of the substrate and the TGSi itself. Where the TGSi is an integrated unit, this percentage is 30%; where the TGSi is composed of discrete units with same luminance on the sloping sides and upper surface of the truncated cones, this percentage is 45%; where the discrete unit has a different luminance on the sloping sides and upper surface of the truncated cones, this percentage is 60%. This Luminance criteria when combined with the slip resistance requirement in AS/NZS 1428.4 sometimes creates a condition that is usually ignored by the end user. The roughened TGSi resulting from targeting a decent slip resistance surface would eventually loss its Luminance by attracting dirt due to the rough surface. Very few TGSi systems could retain their Luminance contrast in the long run unless constant cleaning of its surface is maintained.