For the manufacture of critical structures, it is customary to use GOST standards in construction. Metal stairs and railings belong to this type of structure, therefore, certain standards apply in the design and manufacture of these products.
In the normative documentation and drawings, the requirements for the material used in the manufacture of stairs, the permissible sizes and method of placement of products in the building plan are necessarily indicated.
To describe the conditions of manufacture and installation of metal stairs and fences, GOST is developed:
- GOST R 53254 - 2009. It accumulates standards for the production and installation of metal fire escape ladders and fences for these products in industrial and civil construction;
- GOST 23120-78. Reflects the standards for the production of steel stairs;
- GOST 25772 83. Provides standards and design specifications for fences used in the construction of flights of stairs and for the organization of safety barriers on roofs and balconies;
- GOST 26887-86. The normative document allows you to determine the characteristics of attached metal stairs, platforms, stationary vertical products. In addition, he describes the standards for portable staircases made of aluminum, which are used for construction work.
Standards GOST 23120 78
This regulatory document provides for the arrangement of sites, fences and metal stairs. GOST 23120 78 is required when installing products at an outdoor temperature of up to –65 ° Co.
In construction, during the installation of these elements, the following rules are used:
- product elements must provide resistance to loads within 200-400 s;
- the angle of the flight of stairs to the opposite wall varies between 45-60 degrees;
- the width of the steps varies from 500 to 900 mm with a slope of 45 degrees;
- the width of the steps, with a slope of 60 degrees, should be from 500 to 700 mm;
- the maximum march height varies from 4.2 m for a slope of 45 degrees and up to 6.0 m for a slope of 60 degrees;
- the height of the fence varies from 1000 to 1200 mm;
- structural elements manufactured in the workshop are processed in such a way as not to cause injury to persons using this product;
- to prevent slipping of the human foot on the surface of the steps, their slope should not exceed one degree.
GOST R 53254-2009
This norm governs the production and placement of metal stairs at installation sites for organizing evacuation and emergency descents in industrial and civil buildings, as well as for arranging portable structures.
In the manufacture of metal stairs, Gosstandart provides the following requirements:
- tread depth should not exceed 250 mm;
- the width of each step should be at least 900 mm;
- fence height - not less than 1200 mm;
- if the height of the flight of stairs exceeds 20 m, only marching products are required;
- with a lifting height of less than 20 m, the use of vertical products is possible;
- if two flights of stairs are located in close proximity, between them it is necessary to observe an opening of 750 mm;
- fire escape without fail to protect with anticorrosion paints or varnishes.
GOST on vertical metal stairs prescribes the following standards:
- to ensure safety, the lower span of the fixed staircase must be retractable;
- in the places of installation of embedded parts for the installation of a vertical ladder, there should be no cracks and chips that violate the integrity of the surface;
- fastening of fire ladders is obliged to ensure safe descent of an adult;
- each stage must withstand a vertical load of 180 kgf applied to the center point of the structural element;
- the degree of load for the enclosure must be 54 kgf or more;
- the distance between the extreme points of the steps vertically is limited to 350 mm;
- indent from the supporting surface to the edge of the structure - from 300 mm;
- the distance from the lower point of the extreme step to the surface of the earth is limited to 1500 mm;
- the size of the steps in width is allowed from 600 mm for structures without fencing, and at least 800 mm for products with fencing;
- maintenance of stationary stairs according to building standards is performed at least once every 5 years.
Standards GOST 26887-86
The requirements for metal stairs of inclined and vertical type are established by this standard. The standard takes into account the manufacture and use of aluminum stairs of various types.
State regulation contains the following rules for the production and installation of stairs:
- the width of the flight of steps is set from 0.9 m;
- for one flight of stairs the maximum number of steps is set - 18 pieces;
- the minimum height of the steps is up to 160 mm, and the maximum does not exceed 200 mm;
- the depth of the step (tread) for a vertical staircase should be 0.3 m;
- the tread depth for a spiral staircase varies from 100 mm at the point of internal fastening, to 400 mm at the extreme point near the wall;
- with a stairwell width of more than 110 cm, it is necessary to provide for the installation of two-way fences;
- the height of the enclosure for indoor use varies from 90 cm to 120 cm, with a handrail device with a width of 55-85 mm;
- if the staircase is installed in residential buildings where young children live, the fence is equipped with an additional handrail at a height of 450 mm;
- the gap between the vertical racks of the fence is allowed within 150 mm;
- when designing a flight of stairs in production, it should be borne in mind that the fence is required to maintain resistance of more than 100 kg per meter
Requirements for fencing in accordance with GOST 25772 83
This standard establishes standards for the arrangement of stair railings for marches equipped with more than three steps. It extends to balcony stairs and roof fencing.
When installing iron fences of this type, you must adhere to the rules:
- The resistance of the fence to loads should be at least 40 kgf when applying force in any direction;
- The deflection of the used metal at the specified load should not exceed 50 mm;
- The external supports of the product are treated with special compounds, eliminating the possibility of slipping;
- When organizing paired staircases, the span between the right and left bowstring should not be less than 400 mm and more than 800 mm;
- The act is recommended to be performed within 300-340 mm;
- The passage from the platform from which the ascent is carried out to the extreme step is provided for up to 0.4 m;
- When organizing vertical staircases with a height of more than 5 m, it is necessary to arrange a semicircular rear railing or provide for the fastening of the cable, for attaching a safety belt;
- The distance between the arcs of the semicircular fence is up to 800 mm. To strengthen this design requires the use of three vertical ties. The distance from the extreme point of the arc to the inner surface of the march varies from 700 to 800 mm;
- Maintenance of steel fencing is done once a year. When tested under load, the structural rigidity should be higher than the standard by 20%.
Correspondence of fencing and stairs SNIP and GOST allows you to achieve a safe infrastructure in residential and industrial premises.