Aluminium Stairs - AAI Type AA430
AA430 aluminium stairs are provided in accordance with BS EN ISO 14122 & BS 5395, which should be consulted during the design of any single / multi flight stairs.
Individual stair flights should not exceed 3000mm rise between floor or landing levels, nor contain more than 16 risers.
The preferred stair pitch is from 30 to 38°, although for a private stairs unto approx. 42° is acceptable.
Handrails to the stair flight should be between 900mm and 1000mm high from the pitch line, with handrails to landings 1100mm min – both cases complete with intermediate rails.
Treads and risers should be pitched such to afford comfortable gait - please refer to the table in BS 5395, however approx. 250mm going and 190mm rise is typical.
For stairs with open risers, the nosing of any tread or landing should overlap the back of the tread below by not less that 16mm.
Assembly stairs exceeding 36 risers in consecutive flights, should have at least on change of direction between flights, (min 30°).
Headroom, (vertical distance from FFL), over stairs and landings should not be less than 2000mm with a clearance, (distance perpendicular to the pitch line) of at least 1500mm. For stairs of 3 steps of less this should be increased
Stringers: Generally flat bar, or channel section.
Handrails: As per AAI401 series.
Flooring and Treads: As per AAI410 series.
Finish: Anodised AA20.