Smoke protection of buildings and structures - a set of measures designed to redistribute gas flows, reduce temperature and smoke concentration in case of fire in order to: evacuate people from the building or to the security zone; the presence of people in security zones; restrictions on the spread of dangerous fire factors; enabling effective fire fighting by firefighters. [one]
Smoke and gases generated during a fire penetrate the respiratory system and irritate the mucous membrane of the eyes. To eliminate their harmful effects, it is possible to use personal and group protection. [2]
Group protection is carried out by reducing the concentration of smoke and gases in the room:
- aeration - airing the premises by opening doors, windows or opening structures;
- the use of smoke ventilation;
- use of smoke exhausters, smoke exhaust vehicles;
- smoke precipitation by sprayed water; [2]
- space-planning solutions;
- constructive solutions. [3]
In high-rise buildings, smoke is a particular hazard. In the USSR and Russia, buildings of 10 floors or more are classified as high-rise buildings. The border is determined by comparing with the height of the extension of fire ladders. In Russia, most of the staircases are 30 meters high, so the height of an ordinary multi-story building is limited to a height of 25 ... 30 m. [4]
Space-planning solutions
With space-planning solutions, it is possible to ensure that smoke does not penetrate the stairwell during a fire. To do this, access to the staircase from the floors is made only through the outer air zone through open passages. [five]
Design Solutions
Smoke-tight enclosing structures are used, protection of door and technological openings from penetration of smoke, smoke removal in the desired direction by ventilation with natural motivation. [4]
Naturally induced exhaust ventilation
In systems with natural motivation, smoke removal is carried out through special devices: smoke hatches , smoke shafts with smoke valves; through the inflated lights . [3]
Supply and exhaust smoke ventilation
Designed for the redistribution of gas flows in buildings and structures in the event of a fire in them with the help of permanently installed technical means. Supply ventilation supplies external air to vertical communications (elevator shafts, stairwells), security zones, vestibule locks, creates excessive pressure and prevents the entry of combustion products into them. Exhaust ventilation removes the combustion products from the premises in the event of a fire in them and from corridors and halls in communication with these rooms along the evacuation routes. [6]
For efficient operation, a system with mechanical motivation must have an automatic and remote start. [4]
Safe Zone
A collective means of saving people in a fire. It is carried out in the form of specially equipped rooms inside the building or on its cover. It ensures the prevention of exposure to people living in it dangerous factors of the fire for the entire time the fire is eliminated. The room should be allocated fire walls and ceilings and located so that people have the opportunity to reach a safe area for the necessary evacuation time. [7]
Underground objects
Modern underground facilities are capital facilities designed for long-term operation (100 years or more). During this period, they must meet the requirements of operational reliability, ensuring safety for human life, reliability , durability and maintainability .
Over the past decade alone, a number of major fires have occurred in European countries in automobile and railway tunnels:
- Channel tunnel fire (UK, 11/18/96)
- fire in the Exilles tunnel (Italy, 07/01/97)
- Prapontin Tunnel Fire (Italy, 1/13/97)
- Mont Blanc Tunnel Fire (03/24/99)
- Munich Candid Tunnel Fire (Germany, 08/30/99)
In addition, a number of serious fires were recorded in the subways of Germany, the Netherlands, Italy, Great Britain, and Russia. Since 1990 alone in the Moscow Metro, about 20 fires have been recorded. The largest tragedy related to the fire occurred in Azerbaijan ( Baku , 1995). In the fire, 289 people died and more than 500 were injured of varying severity.
Given the seriousness of the possible consequences of fires in underground structures, special requirements are made to ensure their fire safety. When designing, special technical conditions are developed for the fire protection of structures and the determination of the required fire resistance limits of building structures. Also provide for space-planning, structural and engineering solutions that provide a range of measures for:
- Prevent the occurrence and spread of fire.
- Ensuring fire resistance of building structures and utilities.
- Providing fire detection and suppression equipment.
- Providing smoke protection systems and fire safety ventilation systems.
- Ensuring safe evacuation of people and automatic fire notification and evacuation management.
- Ensuring fire safety of electrical installations, etc.
The most serious attention is paid to the fire resistance requirements of fans used in subways. It should be at least 1 hour at a temperature of 250 ° C.
In this case, it is necessary to take into account the specifics of the subways. So, in foreign subways, for the main (main) ventilation of tunnels and stations, the piston effect from the movement of trains is used, and lightweight special smoke exhaust fans are allowed to be installed, the operation of which is activated automatically in case of fire. Thus, these fans provide the function of emergency smoke removal, after which they must be replaced.
In the CIS subways, the smoke exhaust function is usually assigned to the main ventilation mine fans , which provide the main ventilation of tunnels and stations. The use of light smoke exhaust fans in the conditions of domestic subways is possible, therefore, only if the main ventilation is ensured by the constant operation of shaft fans. The use of smoke exhaust fans for the main ventilation of tunnels and stations is not allowed, since they are not designed for long-term operation and in case of fire can instantly fail.
Failures in the operation of these systems in the event of a fire lead to the inevitable death of the people in it, as well as to serious complications in carrying out emergency rescue operations related to evacuating people and putting out the fire. A striking example of assessing the value of ventilation and smoke exhaust systems was a fire that occurred in 1999 in the Monblan tunnel. The fire killed 39 people, most of whom suffocated from the rapid spread of toxic combustion products due to an outdated and inoperative smoke removal system.
See also
- Firefighting and rescue operations
Links
- ↑ Smoke protection of buildings and structures // Fire safety. Encyclopedia. —M.: FGU VNIIPO, 2007
- ↑ 1 2 Grachev V.A., Popovsky D.V. Gas smoke protection service — M .: Pozhkniga, 2004
- ↑ 1 2 Sverchkov Yu.M. Organization of gas and smoke protection services in fires: Textbook —M.: State Fire Service Academy of the Ministry of Emergencies of Russia, 2005
- ↑ 1 2 3 Grushevsky B.V. Fire prevention in construction - M., 1985
- ↑ Smoke-free stairwell // Fire safety. Encyclopedia. —M.: FGU VNIIPO, 2007
- ↑ Forced-air and exhaust smoke ventilation // Fire safety. Encyclopedia. —M.: FGU VNIIPO, 2007
- ↑ Safe Zone // Fire Safety. Encyclopedia. —M.: FGU VNIIPO, 2007