|Theme: Accessibility :
Accessibility for the Disabled - A Design Manual for a Barrier Free Environment
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II. ARCHITECTURAL DESIGN CONSIDERATIONS
1. PROBLEM IDENTIFICATION
Poorly designed steps that hinder foot movement.
2. PLANNING PRINCIPLE
To provide safe and well-dimensioned staircases for the comfort of all people, especially those with mobility problems.
3. DESIGN CONSIDERATIONS
Differences in level should be illuminated or minimized as much as possible for the comfort of disabled people.
A complementary ramped route, elevator or lift should be provided where there are steps in an otherwise accessible path.
All steps should be uniform.
Circular stairs and stepped landings should be avoided (fig. 1).
Open risers are not recommended.
The minimum width of a stairway should be 0.90 m for one-way traffic and 1.50 m for two-way traffic.
For indoor stairs, the riser should be between 0.12 m and 0.18 m, and the tread between 0.28 m and 0.35 m.
For outdoor stairs, the maximum riser should be 0.15 m and the minimum tread should be 0.30 m.
3.3 Landing (fig. 2) (fig. 3)
An intermediate landing should be provided when the stairs cover a difference in level of more than 2.50 m.
The length of the landing should be at least 1.20 m extending along the full width of the stairs.
3.4 Nosing (fig. 4)
Sharp edges and overhanging nosing should not be used for treads.
Nosing should be flush or rounded and should not project more than 40 mm.
Handrails must be installed on both sides of the stairs and around the landing for gripping (fig. 3).
For stairs more than 3.00 m wide, one or more intermediate handrails could be provided (fig. 5).
The distance between the handrails when both sides are used for gripping should be between 0.90 m and 1.40 m (fig. 5).
Handrails must extend a distance between 0.30 m and 0.45 m at the top and bottom of the stairs (see Railings and Handrails) (fig. 3).
3.6 Tactile marking (fig. 2) (fig. 3)
A textural marking strip should be placed at the top and bottom of the stairs and at intermediate landings to alert sightless people as to the location of the stairs.
The tactile marking strip should be at least 0.60 m wide and should extend over the full width of the stairs.
To guide users with poor vision, the colour of the strip should contrast with the surrounding surface. 3.7 Surface
Landings, treads and nosing should be slip-resistant and free of projections.
Exterior stairs should be pitched forward at 10 mm per metre to drain surface water.
Slip-resistant stair nosing should be used to fix carpets on stairs.
3.8 Emergency stairs
Emergency stairs should be identified by tactile markings.
3.9 Mechanical stairs (escalators)
Mechanical stairs can be provided with an adaptable tread at least 1.20 m long, if they are to be used by persons confined to wheelchairs (fig. 6).
The edges of escalators should be painted in a contrasting colour for the benefit of poor- sighted users.
4. EXISTING CONSTRUCTIONS
When the configuration of the nosing cannot be modified, slip-resistant strip scould be applied to the nosing as an alternative solution (fig. 7).
Slip-resistant strips should be 40 mm wide and should not extent more than 1 mm above the tread surface.
To guide people with sight problems, the colour of the strips should contrast with that of the stairs.
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