2. What is stairs ?
• “A Stair is a system of
steps by which people
and objects may pass
from one level of a
building to another.”
• A stair is to be designed
to span large vertical
distance by dividing it
into smaller vertical
distances, called steps.
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4. • The definitions of technical terms used in connection with
the stairs are as follows:
1) Baluster :-
It is vertical member of wood
or metal supporting the hand rail.
2) Handrail :-
The inclined rail over the
string is known as a handrail.
3) Newel post :-
This is the vertical member which is placed at
the ends of flights to connect hand rail.
4) Soffit :-
It is the underside of a stair.
5) Waist :-
The thickness of structural slab in case of an R.C.C.
stair is known as a waist.
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5. 6) Nosing :-
It is the projecting part of the
tread beyond the face of the riser.
It is rounded to give good architectural effect.
7) Scotia :-
It is a molding provided under the
nosing to improve the elevation of the step.
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6. 8) Step :-
It is a portion of stair which permits ascent and
descent.
It is comprised of a tread and riser.
9) Tread :-
It is the upper horizontal portion of a step upon
which the feet is placed while
ascending or descending.
10) Rise :-
It is the vertical distance
between two successive tread faces.
11) Going :-
It is the horizontal distance
between two successive riser faces.
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7. 12) Flight :-
A series of steps without any platform,
break or landing in their direction.
13) Landing :-
It is the level platform at the top or
bottom of a flight between the floors.
14) Run :-
It is the total length
of stairs in a horizontal
plane, including landings.
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8. 15) Headroom :-
It is the minimum clear vertical
distance between the tread and ceiling.
16) Pitch or Slope :-
It is the angle which the line of
nosing of the stair makes with the horizontal.
17) Riser :-
It is the vertical portion of a step
providing a support to the tread.
18) Line of nosing :-
It is an imaginary line touching
of each tread and is parallel to the slope of the
stair.
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9. 19) Winders :-
These are tapering steps which are
provided for changing the direction of a stair.
20) Strings or stringers :-
These are the sloping wooden
members which support the steps in a stair. They run
along the slope of the stair.
There are two types of string :
i) a cut or open string
ii) a closed or housed string
In the cut or open string , the upper edge is cut
away to receive the ends of steps.
In the closed or housed string, the ends of steps
are housed between straight parallel edges of the
string.
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10. 21) Balustrade or Barrister :-
The combined
framework of handrail and balusters is
known as the balustrade or barrister.
22) Walking line :-
The approximate line of
movement of people on a stair during
ascending or descending is known as a
walking line and it is situated at a distance of
about 450 mm from the centre of handrail.
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11. REQUIREMENTS OF A GOOD STAIR
Provide easy, quick and safe mode of communication between the floors.
Following are the general requirements which a stair should fulfill.
Location :
It should be so located as to provide easy access to the occupants
building.
It should be so located that it is well lighted and ventilated
directly
the exterior.
It should be so located as to have approaches convenient and
spacious.
from
Width of Stair:
It should be wide enough to carry the user without much
crowd
and in convenience. 11
12. Cont’d….
Depends upto its location in the building and type of the
building.
In a domestic building, a 90cm wide stair in sufficient while in
public building, 1.5 m to 1.8 m width may be required.
Length of flight:
The number of steps are not more than 12 and not less than 3.
Pitch of stair:
a comfortable slope is achieved when twice rise plus going is
equal to 60 cm approx. pitch should however, be limited to 30o
degree to 45O
Head Room:
Clear space between tread and soffit of the flight immediately
above it should not be less than 2.1 to 2.3 m.
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13. Cont’d..
Balustrade:
Open well stair should always be provided with balustrade, to
provide safety to users.
Step dimensions:
the rise and tread should be of such dimensions as to provide
comfort to the users. Their proportion should also be such as
to provide pitch of the stair. The going should not be less than
25 cm, though 30 cm going is quite comfortable. The rise
should be between 10 cm to 15 cm. The width of landing should not
be less than width of stair.
Materials of Construction :
The materials used for stair construction should be such as to
provide a) Sufficient strength and b) fire resistance
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14. Steps in a stair may be of
following types :
1) Bull nose step
2) Round ended step
3) Filer
4) Commode step
5) Dancing step
6) Splayed step
7) Winder
Types Of Steps..
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15. 1) Bull nose step :-
It is generally provided at the bottom of the flight ,
projecting in front of the newel post. Its end near the newel forms
the quadrant of a circle.
2) Round ended step :-
A round ended step is similar to a bull nose step
except that it has a semi–circular end which projects out from the
stringer.
3) Filer :-
A filer is an ordinary step of uniform width and rectangular
shape in plan.
Round ended step
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16. 4) Commode step :-
A commode step has curved tread
and riser.
5) Dancing steps or Balancing step:-
Dancing steps are the
winders which do not radiate from a common centre.
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17. 6) Splayed step :-
This step has one end or both ends
splayed in plan.
7) Winders :-
Winders are tapering steps, such as
those which radiate from a point usually situated
at the centre of a newel post.
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19. Classification of stairs
1.straight flight stairs
2.turning stairs
i. Quarter turn stairs
ii. Half turn stairs
a. Dog legged stairs
b. Open well stairs
iii. Three quarter stairs
3.geological or continuous stairs
a. Circular stairs
b. Spiral stairs
c. Helical stairs
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20. Plan Elevation
1.straight flight stairs
• This type of stairs are running continuous
throughout their entire length in one direction
only.
• This type of stairs are used for small houses,
where long but narrow space is available to
accommodate the single flight of stairs.
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24. In case of turning stairs ,flights take turn. The types of
turning stairs are:
1. Quarter turn stairs:
• A stair turning through one right angle is known as Quarter
turn stairs. (L-shaped stair)
• If a quarter turn stair is branched into two flights at a landing is
known as a Bifurcated stair.
• This types of stair is commonly used in the public buildings
near the entrance hall .
• The stair has a wider flight at bottom which bifurcates into two
narrower flights at the landing.
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25. -one turn into left and the other to the right.
•This staircase has either equal or unequal flights.
•When the direction of flight is changed at right angles to the left
or to the right , quarter turn stairs are used.
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27. 2. Half Turn Stairs:
•A stair turning through right angle is known as Half Turn Stairs.
•A half turn star may be of dog-legged type or open newel type .
Dog-legged stair Open newel stair
DOG-LEGGED STAIR
•This type of stairs are used when the length of the staircase is restricted and
width is such that only two flights can be accommodated.
•In this stairs, the direction of the flight is turned by 180 degree, by the
introduction of half space landing at the turn.
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29. • Its name is derived from its appearance in the sectional elevation.
•This stairs are useful where total width of space available for the
staircase is equal to twice the width of steps.
OPEN WELL STAIR
•Space between the upper and lower flights causes half space
landing to be longer.
•In case of open newel stair, there is a well or hole or opening
between flights in plan.
•This well may be rectangular or of any geometrical shape and it
can be used for fixing lift.
•These staircase are useful where available space for staircase has a
width greater than twice the width of steps.
•When the space left is more , a small flight containing three to four
steps may be introduced at the turn , between the two-quarter space
landings.
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31. 3. Three quarter turn Stair
•A stair turning through three right angles is known as a three quarter
stair.
•In this case ,an open well is formed. This types of stair is used when
the length of the staircase is limited and when the vertical distance
between the two floor is quite large.
•This types of stairs are used , when the length and breadth of the
stair room is limited and the vertical distance two floors is quite large.
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33. This type of stair is provided in modern public buildings.
Flights are so arranged that there is a wide flight at the start which
is sub-divided into narrow flights at the mid landing.
The two narrow flights start from either side of the mid-landing.
This type of stair is commonly used in Aristocratic public building
at their entrance hall.
BIFURCATED STAIRS
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35. In this type of stair , the strings and handrails are
continuous without any intervening newel post
and are set out in accordance with geometrical
principles.
A. Circular stairs
B. Spiral stairs
C. Helical stairs
3.GEOMETRICAL STAIR
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37. • Circular stairs or spiral stairs are usually made
either of R.C.C or metal, and is placed at a
location where there are space limitations.
• Sometimes these are also used as emergency
stairs, and are provided at the back side of a
building. These are not comfortable because of
all the steps are winders and provides
discomfort.
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39. Helical stairs
A helical stair looks very
fine but its structural
design and construction is
very complicated. It is
made of R.C.C in which a
large portion of steel is
required to resist bending,
shear and torsion.
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40. Stairs of diff. Materials
Stone Stairs
Timber StairsR.C.C. Stairs
Brick Stairs
Metal Stairs
48. 1.Elevators or Lifts
• The elevators may be used for moving both
people and materials in building having more
than four storey's .
• People movers are described as passenger
elevators.
• The elevators used for moving materials are
called freight elevators.
• For a very tall building , with a large number of
elevators , the space of the lower layers may be
a major portion of the whole building plan.
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50. 2.Escalators
An escalator is a power driven , continuous moving
stair way designed to transport passenger up and
down short vertical distance.
Escalator are used around the world to move
pedestrian traffic in places where elevators would be
impractical.
Principle areas of usages include shopping centers ,
airport , transit system , hotels , public building , etc.
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52. COMPONENTS
• Landing platforms -These two platforms house the curved
sections of the tracks, as well as the gears and motors that drive
the stairs. The top platform contains the motor assembly and the
main drive gear, while the bottom holds the step return idler
sprockets.
• These sections also anchor the ends of the escalator truss. In
addition, the platforms contain a floor plate and a comb plate.
The floor plate provides a place for the passengers to stand
before they step onto the moving stairs.
• This plate is flush with the finished floor and is either hinged or
removable to allow easy access to the machinery below. The
comb plate is the piece between the stationary floor plate and the
moving step.
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53. Truss -The truss is a
hollow metal structure
that bridges the lower
and upper landings. It is
composed of two side
sections joined together
with cross braces across
the bottom and just
below the top. The ends
of the truss are attached
to the top and bottom
landing platforms via
steel or concrete
supports. "freestanding" escalator reveals its
inner components through the
transparent truss 53
54. • Tracks -The track system is built into the truss to guide
the step chain, which continuously pulls the steps from
the bottom platform and back to the top in an endless
loop.
• There are actually two tracks: one for the front wheels
of the steps (called the step-wheel track) and one for
the back wheels of the steps (called the trailer-wheel
track).
• The relative positions of these tracks cause the steps to
form a staircase as they move out from under the comb
plate.
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55. Steps -The steps themselves are
solid, one piece, die-cast aluminum
or steel. Yellow demarcation lines
may be added to clearly indicate
their edges. The steps are linked by
a continuous metal chain that
forms a closed loop. The front and
back edges of the steps are each
connected to two wheels. The rear
wheels are set further apart to fit
into the back track and the front
wheels have shorter axles to fit
into the narrower front track. As
described above, the position of
the tracks controls the orientation
of the steps
View of escalator steps on
continuous chain 55
56. • Handrail- The handrail provides a convenient
handhold for passengers while they are riding the
escalator. In an escalator, the handrail is pulled
along its track by a chain that is connected to the
main drive gear by a series of pulleys. It is
constructed of four distinct sections. At the
center of the handrail is a "slider", also known as
a "glider ply", which is a layer of a cotton or
synthetic textile. The purpose of the slider layer
is to allow the handrail to move smoothly along
its track. The next layer, known as the "tension
member”, consists of either steel cable or flat
steel tape, and provides the handrail with tensile
strength and flexibility. On top of tension
member are the inner construction components,
which are made of chemically treated rubber
designed to prevent the layers from separating.
Finally, the outer layer—the only part that
passengers. Escalator balustrades are usually
made of laminated glass or as steel structures
covered in sheet metal.
An escalator equipped with a
"bellows" handrail. 56
