Extract from Human Rights Commission website: © Australian Human Rights Commission

Tactile Ground Surface Indicators (TGSIs)

Importance of the feature

TGSIs are used to warn people who are blind or vision impaired that they are approaching a hazardous situation such as a set of stairs, a ramp or an overhead obstruction that they might bump into or injure themselves on.

The TGSIs are designed so that they may be read either tactually underfoot; through the tip of a long cane, or visually because of a high luminance contrast - which means that the colour of the TGSIs stands out compared to the surrounding floor/ground surface.

Code requirements

The Building Code of Australia (BCA) specifies where TGSIs must be provided at D3.8 and refers to and requires compliance with the relevant parts of AS 1428.4.

This includes: stairs; escalators; travelators; ramps; and in situations where there are overhead hazards less than 2m above the ground or floor surface. TGSIs would also provide valuable safety information in places such as ‘at grade’ road crossings found in places such as hotel driveways.

AS 1428.4 specifies technical details such as size, location and luminance contrast.

Discrete type TGSIs

Photo 1

Integrated type TGSIs

Photo 2

Photo 1 shows discrete-type and photo 2 shows integrated-type warning TGSIs.

Achieving best results

To be effective TGSI must give a consistent message to people who are blind or vision impaired.

For example, the technical requirements say that TGSI should be setback from the top of a set of steps by 300 +/-10 mm. This means that a person knows that when they identify the TGSI underfoot there will be about 300 mm before the steps begin. If the TGSI are placed right at the beginning of the first step a blind person could miss the first step and fall.

This is achieved by ensuring they are:

  • set back by the specified distance from the hazard, such as the top nosing or bottom riser of stairs or the beginning and end of ramps
  • of the specified depth
  • across the full width of the path of travel, and
  • of high luminance contrast

Common problems and misinterpretations

1. Luminance contrast

Stairs with noncompliant TGSI's

Photo 3

Poor luminance contrast on stairs

Photo 4

The TGSIs in photo 3 and 4 do not meet the specifications of AS 1428.4 as they do not have the required luminance contrast. For TGSIs to be useful to as many people as possible a minimum of 30% luminance contrast compared to the surrounding floor/ground surface is required. These photos also show a number of other non-compliant features in relation to handrails and the lack of colour contrast nosings which are addressed in other parts of this document.

TGSI's curved stairs

Photo 5

Good luminance contast between stairs and TGSIs

Photo 6

Photos 5 and 6 show TGSIs that have high luminance contrast as specified in AS1428.4. Note the correct setback from the top nosings of 300 +/-10 mm and the minimum depth of 600mm.

2. TGSIs on landings of stairways

TGSIs are only required on intermediate landings if there is a break in either or both of the two required handrails across the landing.

As is the case for most people, people who are blind or vision impaired who do not feel comfortable using stairs will use the handrail as a guide for their ascent or descent. Often the handrail will end on a landing where another path of travel enters the stairway, such as a walkway or doorway.

In situations like this the break in the handrail could be misread by a person using the stairway. They may believe they have reached the top or bottom of the stairway, whereas they have only reached an intermediate landing.

Similarly, a person approaching the intermediate landing from a cross walkway or through a doorway has no way of knowing that they are about to enter an intermediate landing on a stairway.

In both these situations TGSIs will need to be applied to the landing.

While the position of TGSIs on landings must be the same as at the top and bottom of stairs the requirement on landings is that they only need be 300 - 400mm in depth. This is because generally a person has a reduced gait on stairways and is more likely to detect the TGSI underfoot at this depth.

Unnecessary TGSIs on landing with continuous handrail

Photo 7

Unnecessary TGSIs on landing

Photo 8

Photos 7 and 8 show incorrect installations as the TGSIs are not required on either intermediate landing as both handrails are continuous.

TGGIs required on landing - handrail broken by incoming path
Photo 9

Photo 9 shows an intermediate landing with one handrail broken, but no TGSIs installed on the landing. TGSIs are required on the intermediate landing as there is a path of travel coming in from the right.

Correct - no TGSIs required on landing
Photo 10

Photo 10 shows the correct interpretation of requirements for TGSIs on an intermediate landing with no handrail break: there are no TGSIs on the landing.