STAIRCASE
A stair is set of
steps leading from one floor to the other.
The room of the building which stair is located is known as staircase.
The opening or space occupied by the stair is located is known as stairway.
Technical terms:-
Step – a portion of stair which permits ascent or descent, it is comprised of a tread and a riser.
Tread – upper horizontal portion of a step upon which the foot is while ascending/descending.
Riser – vertical portion of a step providing a support to thread.
Flight – unbroken series of steps between landings.
Landing – level platform at the top/bottom of a flight between the floors.
Rise – vertical distance between two successive tread faces.
Going - horizontal distance between two successive tread
faces.
Nosing – the projecting part of the tread beyond the face of the riser.
Scotia - molding under nosing to improve elevation of step and to provide strength to nosing.
REQUIREMENTS OF GOOD STAIR:-
Width of stair:
It should be enough to carry the user without much crowd or inconvenience.
It depends upto its location and type of building.
Generally in public buildings 1.5 to 1.8 m width required.
Residential building – 0.9 m width required.
Length of flight:
The no. of steps are not more than 12 and not less than 3.
Pitch of stair:
Comfortable slope is achieved when twice rise plus going equal to 60, pitch should be limited to 30° and 45°.
Head room:
Clear distance between the tread and soffit of flight immediately above it should not be less than 2.1 to 2.3 m.
Balustrade:
Open well stair should always be provided withbalustrade, to provide safety to users. Wide stair should have hand rail on both sides.
Step dimension:
Going should not be less than 25 cm.
Rise should be between 10 cm to 15 cm.
Materials of construction:
It should provide sufficient strength and fire resistance.
DIMENSIONS OF STEP:
For comfort ascent and descent, the rise and tread of step should well proportioned.
Thumb Rules:
(2 x Rise in cm) + (Going in cm) = 60
(Rise in cm) + (Going in cm) = 40 to 45
(Rise in cm) x (Going in cm) = 400 to 450
Rise is 14 cm and going 30 cm as per standard, for every 20 mm subtracted from going add 10 mm to rise
- 15cm x 28cm
- 16cm x 26cm
- 14cm x 30cm
Stair cases are designed as per the specificational need and it connects the different floors in the combined-linkage. Construction of staircase in the practical field requires the accessibility and design.
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