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Types of Civil Defense Shelters & Protective Structures

Author: Andrey Shpak | LinkedIn >

What is Civil Defense Shelter and its Function?

A shelter is a structure designed to protect people and equipment against the harmful effects of blast and other types of threats according to purposes it’s been built for. There are different types of shelters, and they can be categorized according to needed protection level (class), space and configuration demands, number of people and duration of a stay and more parameters. 

Blast protective doors underground shelter
Threat Definition

First, we need to define the existing and potential threats. As history shows, there are many examples related to Chemical, Biological, Radiological & Nuclear (CBRN) events not only during wartime. These events can create a high risk to human lives and potentially cause a large number of fatalities and injuries.
From recent history we can point out the nuclear accident in Fukushima in 2011, the use of nerve agent “Novichok” in Salisbury, an explosion at a chemical plant in northern Spain with the spread of toxic industrial chemicals (TIC), and many examples of biological events. The result of such a mass event can be clearly seen in the current situation with Covid-19.


Besides the CBRN events, caused by accidents related to human factors and natural disasters, there are other potential threats like attacks with conventional or non-conventional weapons, that can create a high-pressure blast wave, as well as fragments, heat, and electromagnetic pulse (EMP).

Potential harm from CBRN events:

  • Chemical - Poisoning or injury caused by chemical warfare agents, harmful industrial or household chemicals.​

  • Biological - Illnesses caused by the infection of dangerous bacteria, viruses or toxins.​

  • Radiological - Illness caused by exposure to harmful radioactive materials.​

  • Nuclear - Life-threatening health effects caused by exposure to harmful radiation, blast effects
    and heat created by nuclear blast.

Radiation conamination zone
Main Types of Shelters:

1. Blast or Bomb Shelter – serves for protect people and equipment from effects of blast and explosion caused by bombing attacks or blasts on hazardous worksites, such as oil & gas refineries, petrochemical factories or other potentially dangerous facilities, as well as against earthquake effects.

2. CBRN shelter – usually combined with blast shelter with addition of life supporting equipment for protection and stay in case of CBRN event and contamination outside. This type of shelters has to be airtight for creating “clean” toxic free area inside. The CBRN shelters equipped with air supply systems for breathing and creating overpressure inside. The overpressure serves as a barrier to prevent the contaminated air from entering the shelter through small openings in the structure walls.

3. Fallout shelter – designed for blocking the radiation from nuclear fallout in case of a nuclear explosion. Many such shelters were built during the Cold War for protecting people in case of nuclear war.

How and What Shelters Can Be Used in Peacetime

The highest class operational shelters like the government, military or command and control shelters must have a fully operational status continuously, but if we talk about the general public shelters for Civil Defense, we can look at the successful example of such shelters in Finland used in everyday life. As the main question in many countries is the budgeting and maintenance of such shelters in the peacetime, the use of the shelter space in everyday life creates a significant cost benefits during the life cycle of the shelter. Examples of such shelters used in peacetime can be warehouses, metro stations, underground car parking, recreational areas e.g. swimming or sports hall, small private shelters as a guest room, movie theatre, storage room etc.


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