Construction regulations provided for stairway width (the distance from the wall to the fence or two guards) at least 90 cm, and distance between the opposite walls of at least 110 cm in smaller sizes for moving flight of stairs furniture and other bulky things (especially when turning 90? ili180?) will be quite difficult. In any case, determining the width of the pace stair railings and take into account the width of the backlash between the marches, which should be about 10 cm per second indicator at a flight of stairs is its inclination (slope), which depends on the width and height of the staircase steps. These sizes depend on many factors, however, they must be such that the ladder was safe and convenient to use. This means that the tread width and height of risers must comply with the average length of the step of man. That is to maintain the ratio between the distance to which man rises or falls, and the distance at which it moves forward. This relation determines the steepness of the stairs, which must be such that the ratio of the height of the march to its horizontal projection was 1:2 – 1:1,75 (ie be in the range of 30?).

In any case, slope of stairs shall not exceed the ratio of 1:1.25 (40?) As on slopes over 1:1 (45?) can only go down backwards and not forward. Use a ladder is inconvenient and dangerous. In calculating the ladder should stick to the rule that all steps within a single march should be the same size in height and width. Deviation in height and width of even a few millimeters at one stage may be affected at the end of a flight of stairs, and as a result – skewed ladder. Formula safety and convenience of the calculation formula of the steps and risers used formula.