A staircase is an integral part of a building; residence, office or public utility. It is designed and built according to the local building codes. A staircase may be straight, circular, flared or spiral. Ergonomic design principles are to be followed in the planning and construction of stairs to avoid inconvenience to the users as well as to avoid accidents.
Staircase Design Principles
Stairs are a series of steps arranged in an order to provide access from one floor of a building to another floor. They should be provided in a convenient location of the building. In case of a multistory building, though elevators will be there for the normal movement from one floor to another, stairs are a must for emergency exit in case of fire or other calamities.
The following are the technical terms associated with a stair.
- Step: The portion of the stair where the foot lands during ascending/descending.
- Tread: The horizontal portion of a step.
- Riser: The vertical portion of a step.
- Stringer: The inclined member which supports the steps.
- Landing: It is the horizontal platform provided at the end of each flight.
- Pitch: It is the slope of the stair.
- Railing: It is the inclined member of a stair which is to support the hand.
- while descending or ascending.
- Baluster: It is the vertical intermediate support of the hand-rail.
Characteristics of a Good Stair
The following are the characteristics of a good stair.
- It should have easy access from all sides of the building
- It should be well ventilated
- It should have wide landing at end of each flight
- Normally there should not be more than 12 steps in a flight.
- The rise and go of the steps should be so proportioned that the ascending and descending of the flight is easy.
- Hand rail must be provided at least on one side of the stair
- The inclination of the stair should be between 30 to 45 degrees.
Types of Stairs
The different types of stairs are:
Construction of Stairs
Stairs are constructed with any of the following materials.
Brick masonry, Stone masonry, Timber, Steel, Reinforced Cement Concrete
Summary of Staircase Design Principles
- Type of Stair: The type of stair depends on the type of building, availability of space and the purpose of stair.
- Rise and Going: The standard rise and tread is 15 x 25 cm. However the dimensions can be changed depending on the actual site conditions.
- Number of rises: The number of rises is equal to the total height of the room dived by one rise.
- Number of treads: This is equal to number of rises minus one.
Buiding Construction and Construction Materials, G S Birdie & T D Ahuja, Dhanpat Rai Publishing Co, New Delhi, 2007
Construction and Foundation Engineering, J Jha and S K Sinha, Khanna Publishers, Delhi, 1977