REQUIREMENTS OF A GOOD STAIR
A. The staircase location should be easy
accessible from the different rooms of the building.
B. It
should have adequate lighting and
arrangements for proper ventilation.
C. It
should have a suficient stair width to accommodate multiple people during peak
hours or emergencies. Generally, the clear width
for interior stairs is at least 500 mm in one- and two-family homes, 900 mm
in hotels, 1.1 m in hotels, apartment buildings and industrial buildings and
other types of apartments.
D. The
number of steps in one flight should generally be limited to a maximum of 12 and a minimum of 3.
E. Head
room should be provided not only to prevent tall people from injuring their
head, but also to give a feeling of spaciousness. Vertical clearance should never be less than 2.15 m.
F. The
size of risers and threads should generally be proportionate for comfort. The
threads should be 250 -325 mm wide, excluding the nosing. Treads less than 250
mm in width should have a nosing of about 250 mm. The most comfortable height
of the riser is 175-185 mm.
Generally
the following formulas should be used
· Product
of riser and tread must be between 400 and 410.
· Riser
plus tread must equal 42.5–43.5 cm.
· Sum of
the tread and twice the riser must lie between 60 and 64 cm.
G. The width of the staircase depends on the
purpose and importance of the building. In the case of residential buildings,
it should be kept at 1 m.
H. The
number of stairs required should be controlled over the maximum floor area
contributing to a staircase. The number of people that can be served by stairs
per floor per unit of 550 mm width of the staircase should be 15 for buildings such
as hospitals and retirement homes,
30 for other institutional and
residential buildings, 45 for storage
buildings, 60 for shops, businesses,
educational, industrial buildings, theatres and restaurants, 80 for
churches, concert halls and museums, and 320 for stadiums and entertainment facilities.
I. The minimum width of landing should be
equal to the width of the stairs.
J. The maximum and minimum pitch should be 40°
and 25° respectively in any stairs.
K. Winders should be provided at
the lower end of the flight, only when it is essential. Generally, the use of
winders in a staircase should be avoided.
L. In open-well stairs in order to avoid the
danger of accidents balustrade must be provided.
M.The
live loads to be considered on stairs have been stipulated by IS:875-1964. The
stairs and landings should be designed for a live load of 300 kg/m2
in buildings where there are no possibilities of overcrowding. In the case of
public buildings and warehouse, where overcrowding is likely, the live load may
be taken as 500 kg/m2.
ALSO READ: Staircase Components or Parts Details | Staircase Design
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