Responsibilities of the controller of the technical condition of vehicles. Pre-trip and pre-shift control of the technical condition of vehicles
The most terrible element at all times was considered fire. A lot of water has flowed under the bridge since Prometheus taught people to use his benefits. But to this day, the issue of fire safety is acute. A fire is especially dangerous in multi-storey buildings that simultaneously accommodate a large number of people.
Types of smoke-free staircases
Most fire victims die from smoke and carbon monoxide poisoning, which is why smoke-free escape routes are so important in this regard if a possible fire is suspected. Flights of stairs were and remain the main ways of evacuation from multi-storey buildings. Building codes and regulations (SNiP) provide for the construction of smoke-free staircases of three types: H1, H2 and H3.
Smoke-free stairs are divided into the following categories by building codes and regulations:
- H1 - stairs, the entrance to which is through an open space outside the building;
- H2 - stairwells with an additional air pressure device;
- H3 - stairwells, the entrance to which is through specially created zones with air overpressure.
General requirements for smoke-free stairs
According to fire safety rules, all smoke-free stairs must be equipped with emergency lighting. The width of the doorway must be at least 1.2 meters, and its height must exceed 1.9 meters. The exits from flights of stairs should not be arranged along the width of the already span. If a smoke-free cage is arranged through a wall with an elevator shaft, then a ventilation hole is arranged in this wall at the level of the upper floor for free air access.
No personal belongings may be placed in passageways to smoke-free stairs and on landings. It is forbidden to independently mount partitions not provided for by the construction project. It is also not possible to cut passages in existing fire bulkheads.
Smoke-free flights of stairs must be equipped with handrails made of non-combustible and slightly heated materials.
Arrangement of smoke-free stairs of the first type (H1)
In buildings above thirty meters, according to " building codes and the rules” staircases should be arranged according to the smoke-free class H1. This type requires stairs that can be accessed from the landings of the floor through an open air space. Design feature such structures in that they are not directly connected to the floors of the building.
Usually, H1 cells are located in the corners of buildings and structures on the windward side and have balcony-like transitions, enclosed by protective screens.
The transition can be made in the form of a loggia or open galleries, the width of the passage must be at least 1.2 meters. The width of the wall between the aisles, as well as the gap to the nearest window, cannot be less than two meters.
The width of the aisle must ensure the transport of fire victims on stretchers!
Installation of smoke-free stairs of the second type (H2)
Stairs arranged according to the H2 type are recommended in buildings whose top floor is located at a height of twenty-eight to fifty meters. The air pressure in the H2 cells is arranged according to the principle of stove draft and can be permanent or open during a fire alarm. It is also possible to have an autonomous backwater device from electric air pumps.
The principle of operation of the smoke-free staircase (PD - pull ventilation system)
Electric pumps providing air pressure must be equipped with uninterruptible power supplies.
The thrust force (or backwater) must be carefully calculated when designing ventilation. The pressure must be such that any person can open the fire doors to the stairs. On the lower floor, the pressure on the door should be at least twenty pascals, on the upper floor - no more than one hundred and fifty pascals.
The entrance to the flights of stairs H2 is arranged through vestibules or locks equipped with fire doors of the corresponding category.
It is advisable to arrange vertical partitions in non-smoke cells of the second category every seven or eight floors. Air support is mounted in the upper zones of the resulting compartments.
Installation of smoke-free stairs of the third type (H3)
The third type of smoke-free stairwells also uses air pressure. The difference from cells arranged according to the H2 type lies in the arrangement of special rooms for the passage of people with self-closing doors on closers. The dimensions of the premises must be at least four square meters. The air supply in cells of this class is carried out both in the space occupied by the stairs, and in the locks arranged in this way. Air draft can be carried out on a permanent basis or turn on automatically during a fire or smoke.
Materials for manufacturing
The main material used in the construction of evacuation smoke-free passages is concrete. Concrete is fire-safe, durable and easy to use. The use of steel structures, such as fences or doors, is an addition to the concrete base. Also, the use of metal spans can be justified in light building structures.
The use of wooden elements is possible in a small volume, for example, wooden door handles or handrails, provided that they are treated with fire-fighting compounds.
Other types building materials when constructing smoke-free stairs, they are practically not used.
Other types of evacuation structures
Other designs can be used as an alternative to smoke-free stairs. For example, staircases of category L1 and L2 with natural light through window openings.
Various outside residential and public buildings are also arranged. In the event of a fire, evacuation is carried out through such stairs and fire-fighting equipment is delivered.
In this article, the device of smoke-free staircases was described in detail. Why are they needed, what are the varieties. In addition, considered general principles fire safety in relation to staircases. Our site is dedicated to stairs and everything connected with them, so ask questions, suggest interesting topics for articles - our authors will fulfill any wishes of site visitors.
