Tactile Indicators And Stair Nosings
Tactile indicators and nosing strips are warning devices for people with low vision. They work on contrast and on texture, and both have to be measured rather than assumed.
Where are tactile indicators required in supported accommodation?
At the approach to stairs, ramps and changes in level, at kerb ramps and crossings on the access path, and where a hazard sits in the path of travel. Stair nosings need luminance contrast on every tread. Both are measured against the adjoining surface rather than selected by appearance.
Tactile ground surface indicators and stair nosing strips exist for people who cannot see a change in level before they reach it.
Which makes them safety devices rather than finishes, and the detail that decides whether they work is contrast.
Luminance contrast is a measured value
Both tactile indicators and nosing strips have to contrast with the surface next to them by a defined amount, and the requirement is expressed as luminance contrast rather than as colour difference.
Two surfaces can look clearly different and fail the measurement. Two surfaces of similar hue can pass it. Which means the selection is made against the measured value for the specific products on the specific adjoining surface, not by eye.
The value changes when the adjoining floor finish changes, so a late substitution of the flooring can invalidate a nosing selection that was correct. The finish decisions behind that are in [flooring selection in an accessible dwelling](/blog/flooring-selection-in-an-accessible-dwelling).
Where tactiles go
**At the top and bottom of stairs,** set back from the edge by the specified distance so the warning arrives before the hazard.
**At the top and bottom of ramps** above the defined gradient.
**At kerb ramps and crossings** on the accessible path from the street or the parking space.
**Where a hazard sits in the path of travel,** including a change in level, an overhead obstruction below head height, or an opening.
The path they sit on is the one described in [access paths, parking and arrival](/blog/access-paths-parking-and-arrival), and the two are designed together because a tactile indicator in the wrong position is a trip hazard rather than a warning.
Warning and directional are different
**Warning indicators,** the raised domes, say stop, there is a hazard.
**Directional indicators,** the raised bars, say the path continues this way.
Using the wrong one, or mixing them, produces a surface that communicates the opposite of what was intended. On a site with an unusual approach, the layout is drawn rather than left to the installer.
Stair nosings
Every tread needs a nosing strip with the required contrast, the required width, and a slip resistance appropriate to whether the stair is internal or exposed.
The strip is also the most worn element on any stair, which means the fixing method matters. A nosing bonded to a finish that later lifts is a hazard, and a nosing that was never going to survive cleaning regimes is a maintenance item from day one, which is part of [maintenance and whole of life costs](/blog/maintenance-and-whole-of-life-costs).
The structural side of the stair sits with the balustrade and threshold work in [decks, balustrades and level thresholds](/blog/decks-balustrades-and-level-thresholds).
Slip resistance is a separate requirement
Contrast tells somebody a hazard is there. Slip resistance decides what happens when they step on it.
Both are specified, and the slip rating required depends on whether the surface is dry internal, wet internal or external and exposed. An external stair in rain is the condition that has to be designed for rather than the dry one.
How it is handled in a factory build
Internal stair nosings are installed in the factory with the stair, under controlled conditions, with the measured contrast verified against the actual installed finish rather than against a sample.
External tactiles sit in the site works, which means they are coordinated with the groundworks and the paving rather than added at the end. That sequencing is part of [landscaping and external works](/blog/landscaping-and-external-works).
What goes in the handover
The product details, the measured luminance contrast values, the slip resistance ratings and the installed locations.
Which matters because a certifier will ask, and because a replacement in five years has to match the original measurement rather than its appearance. That record belongs in [handover documentation and as-built records](/blog/handover-documentation-and-as-built-records).
MADEmodular / MADEbetter.
MADEmodular / MADEbetter.