Written by Kerryn Caulfield, Executive Director, Composites Australia Inc.
Known as ‘tactile ground surface indicators’ (TGSI), directional or hazard warning tiles act as an aid for visually impaired pedestrians, assisting in the navigation of public spaces. TGSIs are effectively a form of braille for the feet that communicates direction and hazards. The tile patterns indicate different safety conditions – raised dots or blisters for ‘caution’ and long parallel strips provide directional cues. They indicate a boundary between footpath and the road and act as silent signs on ‘how close is too close’ or to ‘mind the gap’ when waiting for a train.
Tactiles are designed in different colours to the footpaths and walkways that surround them to visually reflect a change in conditions or direction with TGSIs effectively screaming instructions to all pedestrians, but particularly to those who are visually impaired.
Once an imported product, TGSIs are now being made by Victorian firm Composites Materials Engineering (CME). With its three factories in east and south-east of Melbourne, CME used the extended pandemic lockdowns productively. Brian Hughes, Managing Director of CME explained, “While our number one concern was keeping our workers safe during COVID, we embraced time during lockdowns as an opportunity to assess our product range and to research, develop and test new high volume offerings. TGSIs – which were largely imported – are a natural fit for our capabilities.”
With memories of the pandemic fading, CME Tactiles – which are now branded ‘PremTac’ –comply with industry standards set out in AS/NZS 1428.4.1:2009 and now approved by all state-based road authorities. They are manufactured for use in a range of surfaces and floorings including concrete, asphalt, escalators and travellators, timber and engineered floor and carpet and meet the Australian Standard for slip resistance – AS 4586 – 2013
The PremTac tiles measure 300 millimeters x 600 millimeters and weigh 1.2 kilograms. The range is available in white, yellow, and grey and black through most hardware stores. Installation is straightforward on pre-existing surfaces using screws supplied with purchase and Sika Flex 11-FC.
PremTac tiles are made using CME’s Sheet Moulding Compound (SMC) processing technology. This UV stable materials technology was developed by CME specifically for the tactile product, and is consistent with CME’s core technology for high volume and exacting part reproducibility. CME has evolved from being a key supplier to Australian automotive industry, where volume, quality and performance were key responsibilities to supply. . “The upfront set-up and tool costs for SMC are high, so high volume markets are the natural home for SMC technology. We’re anticipating the TGSIs will be a high-volume business offering product extensions which we are keen to develop. Our other proprietary products such as the portable housing, shower bases and tile trays have grown exponentially in the years since the automotive industry shut down in Australia,” advised Brian.
SMC is a high strength glass reinforced thermoset moulding material which is compression moulded in sheet form using a heated mould under high pressure. CME makes the compound in-house to its own set of formulations. The formulations always involve combining long glass fiber with polyester resin, fillers and additives on its automated compounding line. The fibreglass rovings are chopped in line to a length of typically 25cm which are then impregnated with the resin to produce the Sheet Moulding Compound (SMC)
“When we did our research, it was clear the imported products were made with little knowledge or of Australian conditions, particularly inevitable UV fatigue on plastics. We’ve worked on the chemistry of our UV stabilisers and formulated our compound for harsh Australian conditions to provide the best performing product possible for tactiles to offer prolonged exposure to UV and elevated thermal mass generated by aggregates. This has allowed us to offer our PremTac tiles with a 10 year (conditional) warranty,” says Brian.
Japanese tenji blocks
Tactile ground surface indicators (TGSIs) were first introduced for pedestrian crossing in streets of Japan’s Okayama City in 1967, before being made mandatory by the country’s rail network a year later. The panels, initially known as tenji blocks, were invented by the Japanese engineer Seiichi Miyake to assist a visually impaired friend navigate public spaces.
It wasn’t until 1992, when the Australian Disability Discrimination Act (DDA) passed into law that made it unlawful to discriminate against any person with a disability, that Miyake’s invention of bumpy or striped surfaces became commonplace in Australia.
The work of Seiichi Miyake was honoured with a Google Doodle in March 2019.