The staircase is the main element that we see when entering the house, it has strengths and weaknesses. Its main purpose is the connection of premises located at different levels or floors with each other. Ladders are also used to improve safety, namely: evacuation of people and property, facilitating the work of the fire brigade. Therefore, the staircase should be comfortable, practical and safe - and the size of the steps in this matter plays a huge role. The service life and stability of the stairs depends on how detailed you begin to study the features of construction. Therefore, approach the matter competently and thoroughly.
Each ladder carries a heavy load. Its components are the march and the landing, to which it is directly attached. A march is a construction consisting of a certain number of steps arranged in a row. Steps are the main component of the stairs, their size depends on the slope, height and width of the march, as well as the choice of material. Steps can rest on beams - stringers, which are under the steps, or on the bowstring to which they adjoin. When we rise, the marches are ascending for us, and when we descend, they are descending.
The march from below and from above has the so-called frieze steps: the upper and lower ones, they coincide in level with the landing, and all other steps in the march are exactly the same.
Characterized by riser height h and tread width b. Time and practice have proven that the optimally safe option is the size selected according to the formula 2h + b = 570 ... 640 mm. In millimeters, the standard step length of a person, measured on a horizontal plane, is represented. From the upper formula for determining the dimensions, a second auxiliary one was derived (these two formulas are interchangeable): h + b = 430 ... 470 mm. As well as the formula of a comfortable staircase: b-h=120 mm.
The height of the riser can vary from 135 to 180 mm (average 150 mm). Tread width from 250 to 300 mm. Stairs for general use (main) in EMS (unified model system) have a tread width of 300 mm, then according to the formulas we get: 300 + 2 × 150 = 600.
Often there is a need to save material. Or the place for the operation of the facility is very limited in area: and then we resort to the standards established by SNIP.
The smallest allowable tread width for public use steps is 200 mm. And the maximum is 320 mm. This ensures a stable position of the foot on the plane. A significant increase in the width of the tread is not prohibited by the rules during construction. It just depends on convenience. But practically it is revealed that it knocks down a step. In addition, with a strong cut of the steps, the ascent will be comfortable, but the descent is very difficult, which is also very inconvenient.
As for the winder steps, here the dimensions are drastically different from those stated above. The minimum width from the narrow end of the step should be 100 mm, and the protrusion of the upper step above the lower one should be no more than 30 mm if the structure is wooden and no more than 50 mm if the material is reinforced concrete.
In addition, this method of imposing protrusions saves a lot of space and it is possible to increase the slope of the stairs, which gives a separate plus.
The best option for the slope of the stairs: this is the interval from 23 ° to 37 ° (on average 30 °). The main factor here is space: if it is not enough, then, therefore, the stairs should be steeper.
At an angle below 23°, the stairs are replaced by a ramp (a flat, sloping surface used, for example, near shopping centers, which provides additional traffic and the possibility of movement on wheels).
Exceeding the angle of 45 °, the ladder automatically switches to the type of attached or folding. At the same time, the descent from the stairs with an inclination of more than 45 ° can only be carried out backwards. A comfortable angle of ascent of spiral staircases is 25-35°.
Most often, the standard floor height is 2.7 - 3 meters, with such figures it is convenient to use those based on the safety formula that was mentioned above. If the height of the floor in your house is not divisible by 3, then this is not a reason to be upset or panic. Minimal rounding should be done, keeping in mind that the heights of each riser should be equal. Undoubtedly, there will be a rounding error, but this is fixable in construction technology. It would be more reasonable to add this error to the lower frieze stage.
Why is accuracy so important in designing step sizes? The answer is simple: for safety. Differences, even small ones (in millimeters), increase the risk of injury when descending at night. Usually we do not look down, think about our own, and slowly go down. We trust our muscle memory, and this is a very tricky thing, as it focuses on a familiar and unchanging height.
We highlight only the necessary and important rules when designing stairs:
In order to correctly collect all the information and take measurements to create a future staircase, you need:
The main task in the design of stairs for evacuation is the timely delivery of people to safe places. Therefore, they must be as safe as possible and withstand heavy loads (people can not always keep order).
The main parameters during construction: the width of the stairs must be greater than or equal to the width of the doorway. Slope up to 45°. The size of the steps is 220 mm - height, 250 mm - width, according to GOST 8717.1-84. Also, foreign objects are prohibited, the location of which interferes with the descent down the stairs (permitted technical equipment up to 220 mm from the walls).
The abundance of choice of materials and possibilities baffles many novice builders. But, nevertheless, only the first step is important - to establish a clear idea for yourself what the ladder will be used for, and what criteria should be taken into account. In any case, stick to standard sizes and safety precautions, calculate the height correctly
