For some time now ASN have been testing the luminance contrast of required building elements such as TGSI’s and concrete. Everytime we are presented with a stainless steel version of a TGSI we cringe. These are probably the most difficult to test as the luminance Y values are so varying in the results.
“We test as stated in AS1428.1 – 2009 & AS1428.4.1 – 2009 and the reulsts are across a range of 8 – 70.” – Dale Sheppard. This is not only indicative of the flaws in the testing methodologies it’s demonstrating that the use of stainless steel TGSI’s is a bad idea. The below pictures show just how difficult these types of TGSI’s can be to see.
We often hear from architects and designers that these type of TGSI’s are selected because the look the nicest. Our reply is always “Tell that to the person with the vision impairment who can’t see them but REALLY needs them.”
It’s not good design practice to use this type of TGSI and we would like to request that these be removed from the TGSI market. Or whenever these are specified get them approved as contrasting to the 45% requirement. This is another great over-sight by many. The individual “dots” are called discrete TGSI’s and ARE required to be a minimum 45% contrasting to their adjacent surfaces. Now you try and determine that with a Y value range of 8 – 70. Good luck!!!