Depending of the various arrangement of steps, the stairs are classified under following categories:
Straight stairs – every step is arranged continuously along in one direction. One flight may be split into one or more than one flight by interposing a landing.
Dogged-legged stair type – the stair consists of two straight flights of steps with direct turns between them. This is very useful design if the total width of the stair is just twice the width of the steps.
Open newel stair – there are two or more flights arranging a well or opening between the backward and forward flights. When all the steps are difficult to arrange in two flights, a short third flight of 3 to 6 steps may be provided along the direction perpendicular to the hall.
Geometrical – is a type of open newel stair where the open well between the forward and the backward flight is curved. It may contain different geometrical shape and the change in direction is achieved by using winders.
Circular stair – all the stair steps radiate from a newel or well hole, in the form of winders. The circular stair is adopted at the back side of a building to access its various floors.
Spiral stair – is very similar to a circular stair. It consists of individual steps or treads, connecting to a center column. The overall diameter of the stair may range from 1 to 2.5 m.
Quarter turn stair – The quarter-turn stair can be defined as the stairs that are turned at 90 degrees with the help of level landing.
Bifurcated stair – is most used type in modern public buildings and residential buildings. In this stair, the flight is so arranged that there is a wide flight at the start which is sub-divided into narrow flights at the mid-landing. The narrow flights start from either side of the mid landing.