For buildings to comply with fire regulations and rules, it is necessary to construct stairs in them. They differ both in constructive terms and in their purpose. But all stairs must have the following qualities: be comfortable and safe for people. When constructing modern buildings, it is necessary to comply with SNiPs and GOSTs strictly.
Types of Outdoor Fire Escapes
For stationary outdoor fire escapes, the requirements approved by state standards and sanitary norms and rules (corresponding to GOSTs) must be applied.
Outdoor Fire Escapes Include
- open or closed.
- marching or vertical types.
Vertical stairs are two vertically directed beams with fastened steps and are designed to lift people to a height of twenty meters. Spiral staircases are a type of vertical staircase. They have wedge-shaped steps supported by a narrow edge on the vertical supporting structure of the support pillar, which is located in the center. Such ladders are not used for evacuating people but are intended for specialists who carry out maintenance or access to a fire point.
Marching stairs. They have the highest safety quality. The flights of which alternate (parallel beams fasten steps in the amount of two pieces, located at a certain angle) platforms (horizontal structures with handrails attached to it). If there is one flight within one floor, such stairs are called one-flight. If two flights are two-flight, if three flights are three-flight. In residential buildings, external fire escapes are mounted, one- or two-flight. If the structures belong to multi-story industrial buildings with observation platforms, then three-flight and four-flight staircases are mounted.
Evacuation Structures and Requirements for Them
Fire escapes cannot be installed at the discretion of the customer or builders. The basic requirements and places of their installation are indicated in the state standards. If the building has a height of more than ten meters (from the ground to the cornice), then several exits to the roof of the building must be made via fire escapes located on the outside.
After every hundred meters, residential buildings, buildings of administrative and household and public purposes, which have attic spaces, should have access to the roof. If the building does not have an attic, one exit is sufficient for every 1000 sq. M. cover. As for warehouses and production facilities, fire escapes are made at least every two hundred meters. If the roof drops are more than one meter in buildings or a complex of buildings, it is imperative to install stairs in those places.
Basic Standard Requirements for Fire Structures
All staircases made, including those made by themselves, must comply with safety requirements and established state standards:
- they should be free of sharp edges, as well as details that are an obstacle to the movement of people;
- the length of the canvas should not exceed fifteen meters;
- the canvas is made up to twenty-five centimeters wide: this is the distance between its bowstrings;
- the step-by-step size of the steps should not be more than 35 centimeters;
- a round step in diameter should not exceed 26 centimeters;
- the steps must be exclusively horizontal;
- with a load of 150 kg on a step, the deformation of its middle should not exceed 2% of the staircase width;
- the best option is to withstand a load of 360 kg without deformation of the installation;
- the ladder should not touch the wall; for this, it is equipped with stops of 10-20 cm;
- front staircase structures must be made of their material having anti-corrosion qualities and covered with protective and decorative substances following GOST 9.301 and GOST 9.303;
- the ladder must be constantly functional at temperatures from forty minutes to plus forty degrees, capable of functioning for three minutes at a temperature of plus 600 degrees, and for thirty seconds it must be able to withstand the temperature of an open tribe;
- ТН – an indicator of the ladder’s strength, must have a shutter speed of 50 working cycles.
Basic Requirements for the Construction of Stairs
- the fastening of the front spans is carried out near the window so that it is possible to independently leave the building both during an emergency and with outside help directly from the window sill;
- constructive resolution of almost all stairs makes it possible to increase their length up to 12 floors;
- Stationary-type installations are fixed with brackets under the ridge bar. According to the instructions, it is necessary to use only certified fasteners;
- The fire escape can be moved to the required level using support brackets.
Vertical Fire Escapes and Their Testing
To put into operation outdoor fire escapes and during their use (every five years), it is necessary to check their shapes and sizes, the quality of joints and coatings, and the strength of all its components. Building ladders are checked annually to ensure that all of their fixings are intact. The vertical fire ladder is tested for strength by applying loads for three minutes. If there is no deformation, this design is suitable for further operation.
In this case, the area under the stairs must be protected from the ingress of unauthorized persons. It must be borne in mind that every fifth step of the ladder is subject to verification. After full testing, an official document is drawn up in the form of a conclusion, which is subsequently sent to the appropriate fire department. To make the tests more independent, they involve third-party professionals with special knowledge, experience, and permission to carry out this type of work.
Protective Treatment of Stairs
On external fire-resistant vertical ladders, consistent application of anti-corrosion protection is required. So that in the process of their use, they are not subjected to various negative influences. They are treated with varnish-and-paint materials of various types, and a metal layer is also applied. The protective layer is usually applied at the factory. But there may be exceptions. When it is necessary to restore a site damaged during transportation or installation, work is carried out at the place of installation of the structure.
One of the methods of anti-corrosion protection is to work on the surface of the stairs with a solution containing 95 percent zinc. At the same time, various types of equipment and technologies are used. Galvanized metal is:
- cold type;
- hot type;
- galvanic type;
- thermal diffusion type;
- Gas-thermal type.
A zinc layer applied to the surface of a metal ladder will provide it with reliable corrosion protection. Anti-corrosion treatment of metal stairs uses primers, paints, enamels, varnishes with different compositions. These coatings can be epoxy, perchlorovinyl, silicone, polystyrene, polyurethane, acrylic, oil, alkyd, bitumen type. You can also apply hammer paint, which includes glass and aluminum powder. This paint will contribute to more durable and durable use of the structure and give the stairs an attractive look.
Designers strictly consider the size of the building and its compliance with the future design, determining the optimal material, reliable and aesthetic cladding. Considering such requirements, they will accurately calculate the height, width of the staircase, and all its elements: span, steps, railings.
These ladders are made from
- aluminum profiles and alloys with natural color;
- all their fasteners are made of stainless steel: bolts, screws, springs;
- polyamide for sealing washers and bushings.
All visible parts of the stairs are covered with a high-quality powder coating, and the stair treads are covered with a polyamide anti-slip coating.