/ Product catalogue / Ventilation of shelters / Ventilation systems in shelters / Setting up ventilation systems in sheltersCivil defense shelters must be equipped with ventilation systems that provide purified air and remove heat and moisture from interior spaces. The main operating mode is mode I — clean ventilation, which provides a continuous supply of air for 48 hours.
The air supplied by mechanical ventilation is purified through coarse filters (FYR or similar) with an efficiency coefficient of at least 0.8.
Protective structures require electrically and manually operated ventilation units to be installed, each equipped with a check valve — acting as an air flow indicator. When determining the number of electrically driven ventilation units to be installed in parallel, a correction factor of 0.8 should be applied to their air flow. It is important that the length of the air duct connecting the ventilation unit to the furthest ventilation outlet be no more than 30 meters.
Air ducts for supply and exhaust systems laid outside are made of building structures designed to withstand air shock waves, or are assembled from welded steel pipes and must be laid at a slope of 0.003 or more away from the protective structure (dual-purpose structure). All ventilation openings (air intakes and exhaust devices) must be equipped with explosion-proof devices that protect ventilation systems from excessive air shock wave pressure; an expansion chamber must be installed downstream of them. In this case, condensate drainage should be provided upstream of the explosion-proof device.
Ventilation of rooms intended for installing autonomous power supply, as well as clean and contaminated areas of sanitary inspection rooms, should be provided through separate air ducts from the air ducts of other ventilation systems. Air intake grilles should be located outside the possible debris of buildings and structures.
A fallout shelter is an engineered structure, partially equipped with special equipment, designed to protect the shelter from ionizing radiation and conventional weapons. A fallout shelter is not an airtight structure and is not equipped with airtight valves and air purification systems that use filter ventilation units. Fallout shelters (FSs) should be equipped with mechanically driven ventilation. In FSs' rooms, the maximum allowed indoor climate parameters and gas composition of the air are determined depending on the number of people taking shelter, as per mode I (clean ventilation). Fans for ventilation systems in FSs that do not have a protected autonomous power supply or diesel power plant (DPP) should be equipped with an electric and manual drive. All ventilation openings must be equipped with dust filters with an air flow resistance of at least 5 N/m² (0.5 kgf/m²).
Shelters and shelter-like dual-purpose structures (DPS) are airtight protective structures equipped with special engineering equipment and life support systems, in particular filter ventilation and air regeneration systems. They provide continuous shelter for persons to be sheltered for 48 hours.
They guarantee comprehensive protection against weapons of mass destruction (nuclear, chemical, biological weapons), as well as conventional weapons.
for an emergency pressure of at least 0.1 MPa (1 kgf/cm²), with manual drive for dimensions up to 600 mm inclusive and with electric drive if there is a DPP or dimensions over 600 mm.
For their inspection and cleaning, hatch inserts are provided, which are mounted facing the shock wave after the airtight valve.
Air ducts of shelters and shelter-like DPSs, laid inside rooms to airtight valves, connecting air ducts between air intakes for clean ventilation and filter ventilation, as well as pipes for installing airtight valves in walls, shall be made of steel pipes with a wall thickness of at least 8 mm.
The ventilation system for shelters and shelter-like DPSs should be equipped for two modes of operation:
The amount of outdoor air supplied to the protective structure (dual-purpose structure) must be as follows:
The operating air pressure for mode II should be 50 Pa.
For filter ventilation and regeneration, a sufficient air volume should be recirculated to maintain the volume of air supplied during clean ventilation in the system: for shelters and DPSs with electric fans, at least 70 % of the air volume must be retained in the system.
Air intakes should be located out of the possible debris zone of buildings and structures.
Air intakes for filter ventilation systems may be located in areas where debris may accumulate and in the vestibule
of a shelter (dual-purpose structure).
It is recommended that the air intake box for clean ventilation of shelters and DPSs (mode I) be connected to the emergency exit from the shelter.
To ensure separate exits from the shelter or DPS to the surface and re-entry in filter ventilation mode, ventilation of the vestibule or vestibule-airlock of one of the entrances should be provided.
In this case, the volume of air supplied to this vestibule per hour should be at least 25 times the volume of the vestibule with a ventilation duration of up to 6 minutes.
Ventilation of the vestibule (airlock) should be carried out by flowing air into the shelter/DPS using overpressure valves, which should be installed on the inner and outer walls of the vestibule (airlock), with an explosion-proof device installed on the external pressure relief valve (KNTK) or directly from the filter ventilation system.
When installing ventilation, additional exhaust ventilation should be provided for bathrooms.
The air flow in ventilation mode I should be 100 m³/h for each toilet and 50 m3/h for each urinal.
For ventilation mode II, it is allowed to reduce the specified air flow rate from the toilet to 25 m³/h.
Mode III – internal air regeneration – is intended for shelters and shelter-like DPSs located in areas where there is a risk of dangerous air contamination with combustion products, in areas of possible chemical contamination or flooding.
In full isolation mode (mode III), the shelter is ventilated as follows:
In partial isolation mode (mode III), the standard operating air pressure of 20 Pa is maintained by supplying outdoor air purified using special filters.
Sequence of filter application:
