Stair | Properties & Technical Terms of Stairs

Stair
Properties of Stair
Technical Terms of Stair!

• A stair may be defined as a series of steps suitably arranged to connect different floors of a building.
• The room or enclosure of the building in which the stair is located is called a staircase.
• The opening about space occupied by the stair is called as a stairway.
• In a residential building, the stair should be centrally located to provide easy communication to all the rooms.
• During public buildings, stairs should stand located near each entrance.
• That is built up of timber, bricks, stones, steel either RCC.

Technical Terms of Stair

• Steps:- Some portion of a stairway consisting of the tread also riser which permits ascent about descent from one floor over another.
• Tread:- This horizontal upper part of a step on which pad is placed in ascending either descending stairway.
• Riser:-  Some vertical portion of a step giving support to tread.
• Flight:- Each series of steps without either platform about the landing.
• Landing:- A platform or resting place provided between two flights.
• Nosing:- The outer projecting edge of a tread is termed as nosing. Nosing is usually rounded to give a good architectural effect to the treads.
• Winders:- Those are reducing steps which are provided during changing the direction about a stair.
• Soffit:- It is the undersurface of a stair.
• Handrails:- It is supported on balustrades and usually runs parallel to the slope of stairs.
• Baluster:- It is a wooden, metal or masonry vertical member supporting a handrail.
• Newel:- It is a wooden or metallic post supporting the handrail and is usually provided at the hand, foot or at points where the balustrade changes its direction.
• Pitch or slope:- It is the angle which the line of the nosing of stair makes with the horizontal.

Requirements for good Stairs

Location

• It should be located such that sufficient light and ventilation will come in a stairway.
• If possible it should be located centrally to be easily accessible.

Width of a Stair

• The width of a stair varies with the situation and the purpose for which it is provided.
• In a public building, where there is a regular traffic of people, its width should be sufficient.
• In a residential building may be just the minimum.
• The usually adopted an average width for public and residential buildings is 1.8 m and  90 cm respectively.

Length of Flight 

• For the comfortable ascent, the number of steps in a flight should be restricted to a maximum of 12 and a minimum of 3.

Pitch of Stair

• The slope of the stair should never exceed 40° and should not be flatter than 25°.

Materials

• Some stair should preferably last constructed of materials which maintain fire-resisting qualities.

Landing

• The width of each landing should no be less than the width about the stair.

Step proportions:-

• The rise also treads of each step in a stair should move of uniform dimensions completely.
• Number of riser = Total height of floor / Height of riser
• Number of trade= Number of riser – 1

Trade & Rise proportion of Stairs

• The size of a tread and riser varies with the situation of the stair and the purpose for which it has to be provided.

Near a general, these following thumb rules remain considered

1. Going in cm * Rise in cm == 400 into 410 approx
2. Going in cm + (2 x Rise in cm) == 60 approx

• Adopt the standard size of going and rise as 30 cm and 14 cm
• For residential buildings- Trade = 250 mm to 300 mm or Rise = 150 to 180 mm
• For public buildings- Trade = 270 mm to 300 mm or Rise = 130 to 160 mm