FBE04 BUILDING CONSTRUCTION AND MATERIALS Stairs Wong Chear Ching chearching@gmail.com

STAIRS 1

Why do we need to learn about Stairs Interconnectivity of space Accessibility Circulation / Flow Fire escape Functional requirements Design considerations Types of Stairs

OBJECTIVES State the functional requirements of stairs Define the various terminology related to stairs Identify the different forms of staircase construction and list the design considerations of staircases. Describe the characteristics of different staircases and compare their advantages and disadvantages. 4

Introduction Staircases provide a mean of access between different floor levels within a building 5

Functions of Stairs To allow normal access from floor to floor To allow escape from upper floors in the event of fire 6

Functional Requirement Strength & stability Fire Resistance Sound Insulation Aesthetics

CLASSIFICATION Shape Materials flight Concrete Straight Timber Quarter turn Steel Brick Dog leg Spiral

Configuration of Staircases

Configuration of Staircases

Straight Flight Stairs

Quarter Turn Stairs

Half Turn (dog-leg) Staircases

Spiral Stairs

CLASSIFICATION Shape Materials flight Concrete Straight Timber Quarter turn Steel Brick Dog leg Spiral

Timber Stairs

Concrete Stairs

Brick Stairs

Metal Stairs

Composite Stairs combination of at least two different materials made of concrete or steel composite stairs are steel support with concrete or timber treads

Components of A Staircase Treads and Risers Strings Closed String Open or Cut String Landings Balustrades Open balustrade Closed balustrade

Cut to the profile of the treads and risers to support them Open Strings

Encloses the treads and risers which it supports and top edge protrude 50- 63mm above nosing Closed Strings

Landings

Handrail,Baluster & Newel Post Handrail Newel post 24

Consists of framed or unframed panels acting as baluster to support the handrail Closed Balustrades

Vertical balusters spaced at certain interval to support the handrail Open Balustrades

Handrails & Balustrades

Stair Terminology

Stair Terminology

Basic Design Considerations The risers and treads within each flight of stairs shall be of uniform height and size. The height of a riser shall not be more than 175 mm. The width of a tread shall not be less than 275 mm. The width of a tread of any staircase in any residential unit shall not be less than 225mm. The width of a tread of any staircase in any industrial building shall not be less than 250mm. The width of the tread of any tapered step shall be taken as that when measured at a distance of 500mm from the narrower end. Riser Tread

Basic Design Considerations The pitch of the stair shall be a maximum of 42°. The clearance of headroom should not be less than 2.0 m measured vertically above pitch line.

Basic Design Considerations A landing shall be provided at every floor level and door opening. Except for spiral staircases, an intermediate landing shall be provided in between floor levels at intervals of not more than 18 risers. The clear width of any landing, measured from the handrail or kerb (whichever protrudes further into the landing) to the wall or external railing of the landing, shall not be less than 900 mm 32

Width of Stair & Landing (min 900mm)

Basic Design Considerations A handrail shall be provided on at least one side of the flight of staircase The height of the handrail shall be between 750mm and 1000mm above the pitch line. Where there is a vertical drop in level of 1.0 m or more (for a staircase with more than say 5 steps), appropriate measures shall be taken to prevent people from falling from a height. Where a barrier is used to prevent falling from a height, the barrier shall not have any feature that facilitates the climbing of the barrier. The height of a barrier shall not be less than 1.0 m. The height of a barrier at the flight of stairs is measured vertically from the pitch line to the top of the barrier.

Basic Design Considerations Handrails shall: have a circular section of 32mm to 50mm in diameter or an equivalent gripping surface; and have a clear space between the handrail and all wall surface – (i) not less than 40mm; or (ii) at least 60mm where the wall has a rough surface. A recess containing a handrail shall extend at least 450mm 35 above the top of the rail

Basic Design Considerations For a flight of staircase, In all buildings, except for industrial buildings, any triangular opening or void formed around a tread, riser and the bottom edge of the barrier, the size of any opening or gap shall not be large enough as to permit the passage of a sphere of a diameter of 150mm. In all buildings, except for industrial buildings, the gap size between any two consecutive steps shall not be large enough as to permit the passage of a sphere of a diameter of 100mm; and In industrial buildings, the gap size between any two consecutive steps shall not be large enough as to permit the passage of a sphere of a diameter of 150mm.

Basic Design Considerations Number of risers is not to exceed 18 in any flight of steps. Except for spiral, circular or geometric staircases, an intermediate landing shall be provided in between floor levels at intervals of not more than 18 risers. The width of landings should not be less than the width of the stairway.

Concrete Staircases Most common Advantages good fire resistance Strong better sound insulation Disadvantages Slow in erection – wet process Proper training required

Concrete Staircases Requirements: Concrete Grade 30 or above Minimum concrete cover 20 mm Waist thickness between 100 to 250mm Mild steel or high yield steel bars can be used as reinforcement Handrail to be at least 900 mm above the pitch line

Concrete Staircases Hand- railing Min 900 mm Concrete cover Waist thickness

Concrete Staircases Finishes Warehouse – natural finishes. Add carborundum dust / rubber strips for slip resistance PVC tiles Rubber tiles Carpet mats

Concrete Staircases

Precast Staircases Advantages Better quality control Saving in site space Faster construction Installation is simple. Disadvantages Requires mass production.

Precast Staircases Precast Concrete Treads

Precast Staircases

Precast Staircases