Buildings present unique accessibility challenges and barriers that can prevent people with disabilities from accessing and using spaces safely and independently. Tactile ground surface indicators, also known as tactile warnings or domes, are an important accessibility feature that alerts individuals, especially those who are blind or have low vision, to potential hazards or decision points using tactile cues. When installed according to established tactile standards in building entrances and common areas, tactile domes enhance safety and wayfinding for all individuals.
Tactile domes are a standardized feature prescribed by tactile standards developed through extensive research to address the built environment needs of individuals with vision loss. This blog post will explore tactile standards for building accessibility and examine the role of tactile domes in creating safe, independent access. Let's begin by defining tactile standards and understand their purpose.
Tactile standards are technical specifications and guidelines established through research and expert consensus to address accessibility barriers faced by individuals with disabilities, including those with vision impairments. Tactile standards prescribe design criteria and placement requirements for tactile ground surface indicators, which alert pedestrians who are blind or have low vision to hazards, obstructions, level changes and decision points using touch as opposed to sight.
Tactile standards aim to ensure consistent use of tactile cues that people with vision loss can readily learn and apply universally. By standardizing the design and installation of tactile warnings across jurisdictions and contexts, individuals gain the confidence of understanding what a sensed surface feature communicates regardless of location. Standard tactile cues remove the need for persons with low or no vision to question what a tactile element means based on varying designs. This predictability and reliability enhances independence and participation.
Two tactile types recognized in international standards are tactile attention indicators and tactile directional indicators. Tactile attention indicators signal decision points requiring judgment, such as at staircases or intersections. Tactile directional indicators guide pedestrians along a suggested path of travel through elongated bars oriented parallel to the intended direction. These tactile standards inform accessible design in building exteriors, including entrances, paths of travel, stairs, ramps and drop-offs. Let's examine some key standards and their focus on tactile cues.
CAN/CSA-B651-12 Accessible Design for the Built Environment provides guidelines applicable to structures and fixed equipment serving multiple end uses, including residential, institutional, assembly, mercantile, business, industrial and storage. This standard prescribes that where changes in level pose a risk for collision or disorientation, tactile warning surfaces complying with ISO 23599 are provided at stairs, ramps, curb ramps, stairs and landings.
Under development is CAN/CSA Standard CAN-ASC-2.3 Model Standard for the Built Environment-Accessibility for federally regulated entities as defined in the Accessible Canada Act. This will establish technical requirements for federally regulated entities to comply with the Accessible Canada Act built environment standards. It is intended to exceed minimum requirements of the Ontario Building Code and foster consistent application.
CAN/CSA-B651.2 Accessible design for self-service interactive devices including automated banking machines expands requirements in B651 to cover touchscreens specifically. It establishes criteria for tactile boundaries, text size, contracts and device usability. CSAB651.2 aims to support independence for people with various disabilities interacting with touchscreen and cash machines around Canada.
These lead standards endorse tactile attention indicators providing critical information about upcoming hazards or decisions for travelers with sight impairments underfoot through cane detection. Let's explore tactile attention indicators in more detail.
Tactile attention indicators are the circular truncated domes recommended by CAN/CSA Standard B651 and ISO 23599. They are designed to alert pedestrians who are blind or have low vision to potential obstacles, decision points or level changes ahead that require manoeuvring. Due to their discernible shape and dome height, tactile attention indicators are detectable under the tapping of a white cane.
When installed according to standards, tactile attention indicators have the following form and sizing:
Circular, truncated dome shape conforming to a 600 mm long by 610 mm wide field
Dome height is 4-5 mm
Dome diameters range from 12-25 mm with prescribed centre-to-centre spacing based on size
Arranged in a square grid formation perpendicular to the direction of travel
Their standardized shape, size, dimensions and grid pattern make them distinguishable to touch. This tactile cue communicates where a person is approaching a potential hazard or junction requiring judgment, allowing safe navigation.
Tactile attention indicators should be installed at specific locations of potential safety risk or decision points, including the top and bottom of stairs, stair landings where doors lead into the stairwell, and edges of platforms without protective barriers and ramps. At the curb ramps, ramps should be located at the base of the curb beyond the flared sides or dropped sections. Where level changes occur along exterior paths of travel, tactile attention indicators alert the user to the location of an elevation change.
Their standardized design and placement according to standards allow tactile attention indicators to be universally recognized regardless of location. Individuals learn to detect and interpret their meaning through long cane orientation and mobility (O&M) training as part of developing independent travel skills with a white cane.
While an important communication tool, tactile attention indicators are just one of the many elements considered by standards related to accessible design for the built environment. Let's review a few additional standards that inform how buildings and exterior spaces can better integrate accessibility for persons with disabilities.
As mentioned, CAN/CSA-B651 Accessible Design for the Built Environment provides guidelines for structures and equipment serving multiple purposes, including residential, institutional, assembly, mercantile, business, industrial and storage uses. It outlines requirements ranging from parking and transportation facilities to signage, lighting, doors and controls.
CSA/ASC B652 Accessible dwellings addresses residential occupancies and provides requirements for visiting, living and sleeping spaces in addition to plumbing fixtures and associated elements including kitchens, storage and laundry areas.
CAN/CSA-B651.1 Fixed ladders, fixed stairs, guards and handrails establishes criteria for elements that help address elevation changes including their dimensional requirements and loading capacity.
These standards address critical areas for safe, independent access and mobility in both private and public realm environments. Reviewing them for their dimensional, technical and sensory guidance can support integrated solutions that meet the needs of all users.
Accessibility should be at the forefront of every design project. But Tactile Solution Canada takes this a step further, providing practical guidance to help proactively plan accessible environments from the start. By accounting for a diversity of needs and abilities, these standards ensure buildings, parks, and public facilities are easy for all to use - minimizing costly retrofits down the road. Following these leadership guidelines helps fulfil our shared goal of an inclusive society where everyone belongs.
