AR163 Module 3 Lecture 2 PDF

STAIR  EVOLUTION OF STAIRCASE Staircase are one of the oldest building elements in architectural histories…. Reflecting the prevailing philosophies and symbolic language. WHY DO WE NEED STAIRCASE To protect people from injuries and to facilitates access d...

STAIR  EVOLUTION OF STAIRCASE Staircase are one of the oldest building elements in architectural histories…. Reflecting the prevailing philosophies and symbolic language. WHY DO WE NEED STAIRCASE To protect people from injuries and to facilitates access during movements from one level to the another in a building. LOCATION OF STAIR Stair should be placed at a central place in the building so as to give shortest access to all rooms. It should be well ventilated and airy. 1. LOCATION It should preferably be located centrally, ensuring sufficient light and ventilation. 2. WIDTH OF STAIR The width of stairs for public buildings should be 1.8 m and for residential buildings 0.9 m. 3. LENGTH The flight of the stairs should be restricted to a maximum of 12 and minimum of 3 steps. 4. PITCH OF STAIR The pitch of long stairs should be made flatter by introducing landing. The slope should not exceed 400 and should not be less than 250. 5. HEAD ROOM The distance between the tread and soffit of the flight immediately above it, should not be less than 2.1 to 2.3 m. This much of height is maintained so that a tall person can use the stairs with some luggage on its head. 6. MATERIALS Stairs should be constructed using fire resisting materials. Materials also should have sufficient strength to resist any impact. 7. BALUSTRADE All open well stairs should be provided with balustrades, to avoid accidents. In case of wide stairs it should be provided with hand rails on both sides. 8. LANDING The width of the landing should not be less than the width of the stair. 9. WINDERS These should be avoided and if found necessary, may be provided at lower end of the flight. Location of Stairs It should be so located as to provide easy access to the occupants of the building. It should be so located that it is well lighted and ventilated directly from the exterior. It should be so located as to have approaches convenient and spacious. It public building it should be located near main entrance and in residential building it should be placed centrally. PRINCIPLES TO BE OBSERVED WHILE PLANNING AND DESIGNING A STAIR 1. Width of Stair: It should not be less than 1.00m. 2. Length of flight: The number of steps in a single flight should not be more than 12. 3. Pitch of the stair: It should be between 25 too 40 o 4. Width of landing: It should be 150mm, more than the width of stair. 5. Winders or kite steps: Odd shaped steps should be avoided and incase found necessary. These should be provided at the start of a stair. 6. Han-rails: It should be 750 to 850 mm in height from the top of respective step or landing. 7. Step proportions: The size of rise and tread in a stair should be kept uniform through out the whole stair. 8. Headroom: Minimum of 2000mm of clear headroom is required above the pitch line Following proportions are recommended: (i) Residential buildings- Tread=250 mm Rise=160 mm (ii) Public buildings - Tread=300 mm Rise=150 mm (iii) Industrial buildings, Railway station, etc Tread =not less then 250 mm =250 to 300 mm Rise =not less then 150 mm =150 to 190 mm Otherwise work out the sizes of rise and tread by using any one of the following proportions (i) (2xRise)+(Going), In mm=550 to 600 mm (ii) Rise x tread, both in cm = 400 to 410 cm2. (iii) With basic proportion of going 300 mm and rise 150 mm, add 10 mm to rise for every 20 mm deduction from going e.g. For a going of 280 mm the rise will be 160 mm. The above rules act as guide but the actual sizes depend upon the availability of space, while planning stairs practical-field. Stair Parts The upper horizontal of a step upon which the foot is placed while ascending or descending It is the vertical portion of step providing a support to the tread This is an unbroken series of steps between lading Its level platform at the top or bottom of a flight between the floors Main reason for lading is providing some rest for the climber Vertical distance between two successive tread faces. It’s the horizontal distance between two successive riser faces It is the projecting part of the tread beyond the face of the riser It is the underside of a stair These are the sloping members which support the steps in a stair Newel post is a vertical member which is placed at the ends of flights to connect the ends of strings and hard rail… It is vertical member of wood or metal, supporting the hand rail It is a rounded or moulded memoire of wood or metal following generally the contour of the nosing line and fixed on the top of balusters It is the minimum clear vertical distance between the treads and overhead structure  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. 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 moulding provided under the nosing to improve the elevation of the step. 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. 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. 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. 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. 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. Types Of Steps.. Steps in a stair may be of following types : 1) Bullnose step 2) Round ended step 3) Filer 4) Splayed step Commode step 5) Dancing step or Balancing step 6) Splayed step 7) Winder 1) Bullnose 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 bullnose 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 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. 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.  STAIR GEOMETRY Stair safety and geometry are related- rhythmic movement along a straight line is important for safe ascent or descent  STAIR ANGLES According to AS 1657-1992 (Fixed platforms, walkways, stairways & ladders- Design, construction & installation), stairways should be angled between 26.5 0and 45 -0That’s between 1 in 2 and 1 in 1 450 Rise = 1 Rise = 1 26.50 Going = 2 Going = 1  Stairway Landings Stairways landings must be at least 30 inches deep and 22 inches wide at every 12 feet or less of vertical rise Unprotected sides of landings must have standard 42 inch guardrail systems  Platforms and Swing Doors Where doors or gates open directly on a stairway, provide a platform that extends at least 20 inches beyond the swing of the door. STAIR CHAIR STAIR STEPS Handrail & Stairrail T I M B E R N E W E L P O S T T I M B E R B A L U S T E R S S T E E L B A L U S T E R S S T O N E B A L U S T E R S  Different materials that are used in a stairs and there benefits? TIMBER – Gives design flexibility, it is lightweight and easy to install. GLASS – Gives an openness and a clean airy feel to a room that other materials just don’t provide. STAINLESS STEEL – Is used for handrails and balustrade. It is easy to keep clean and is non-corrosive so it doesn’t rust. STEEL – Hardwearing and incredible strength. This allows you to increase the span and length of the stair and makes it great for commercial stairs that are exposed to high traffic. STONE – Marble stairs can have creative inlayed geometric or floral patterns and can also be carve into vertical slabs or tiles, granite gives a rich shiny look, sandstone provides a more rustic feel. One can choose different stones in combination as per tastes, needs and the décor of the surrounding area.  STAIRCASE LIGHTING Stairway Lighting is required, with light switches at top and bottom of the stairway if the stairs encompass more than three stair treads (Canada) or six stair treads (U.S.). List of Common Stair Lighting Defects Interior light fixtures or switches used on outside stairs - not weather protected (see photo at left) Stair lighting missing or light switches not present at both top and bottom Stair light switches not properly located (wrong height) Stair lights burned out, damaged, not working Stair or landing lighting too dim - insufficient lumens Latest Stair This section is a showcase of the more recent stairs that are use nowadays. The combination of glass, timber, stainless steel, wires are being used widely. The large landing at the bottom of the stair, the combination of both open and closed risers Feature Stair Feature stairs can be either classic or contemporary in design because what defines them is not so much their style as their prominence and importance to the interior design as a whole. Feature stairs are a statement, they represent the designer’s commitment to complete harmony of the space. Contemporary Stair Contemporary stairs offer the designer opportunities that classic designs don’t – individuality and design. Contemporary design can be gloriously simple using clean lines or gracefully curved. Curved Stair Curved staircases that have a highly complex structure, must also meet in-depth building regulations. It can be a paradox that the staircase must marry perfectly with the space provided and appear simple and almost effortless when completed. Modern Stair Modern stairs typically look clean and sleek. They often incorporate material such as glass and stainless steel and create a focal point for the home. With so many options now available in stair components and materials, modern stairs allows the designer to let their imaginations run wild. Classic Stair Classic stairs are reflective and have in the past at times fallen victim to the parody syndrome where grand designs of say the Victorian era are reproduced with little regard to detail, form or truth, only imitation. Traditional Stair Creating staircases of style and character, in the true traditions of a particular architectural era is something that you should only trust to the experts. Whether you are renovating, extending or building from scratch in any of the classical styles, you deserve to have attention paid to the integral design of the stair as well as the finer details. Commercial Stair Built commercial stairs for retail business such as cafes, nursing homes and apartment buildings, to name a few. The high quality materials should be used, it will ensure that the stairs will stand the test of time, particularly for commercial stairs which are subject to high foot traffic.