Scope of protection
Shelters/nuclear shelters must be able to withstand the effects of modern weapons, i.e. they must primarily provide protection against nuclear, biological and chemical warfare agents as well as close-range hits from conventional weapons.
There is currently no shelter concept for civil shelter construction in Germany. Therefore, we, the German Shelter Center, offer civil shelters in Germany based on the current Swiss shelter concept.
The following lists, among other things, the scope of protection of shelters according to the Swiss classification of basic protection according to the shelter concept TWP 1984 of the Swiss Federal Office for Civil Protection (FOCP).
What does a nuclear safe shelter protect against?
In peacetime, protective structures can generally be used in a variety of ways, such as as a hobby room, storage and wine cellar or even as a soundproof music room.
In the event of disasters and emergencies, the occupants of protective structures can be protected from the effects of natural or technical hazards.
In the event of armed conflict, the protective structures protect the population from the effects of nuclear and conventional weapons (A and K weapons) as well as from the effects of biological and chemical weapons
(B and C weapons). The protective structures are designed and dimensioned in accordance with the required scope and level of protection (basic protection) so that damage from weapon impact is accepted, the use
the shelter and the security inside remain guaranteed.
The construction requirements provide protection against all effects of nuclear weapons at a distance from the explosion center where the air blast has decreased to approximately 100 kN/m² (1 bar).
Air blast propagation and shock load of a protective structure during a nuclear explosion
with detonation point on the ground Source: TW Schock 2021
The construction requirements provide protection against all effects of nuclear weapons at a distance from the explosion center at which the air blast has decreased to approximately 100 kN/m² (1 bar).
Scope of protection using the example of the Hiroshima atomic bomb
At a distance of only 0.8 km from the drop point of the Hiroshima atomic bomb, people in such a shelter would have remained unharmed. People outside the shelter would have been seriously injured or killed.
Protection against conventional weapons
Protection against:
Explosive projectiles and bombs
Incendiary weapons
FAE weapons (pressure wave through fuel-air cloud)
Due to the reinforced concrete shell, the surrounding soil and the building above it, the shelter also offers reliable protection against explosive projectiles from conventional weapons.
Only larger projectiles with a delayed fuse that hit the bunker/shelter directly or at a short distance (crater radius) can cause damage. According to studies, the probability of a direct hit from conventional weapons, even in extreme forms of attack, is very low.
Infantry weapons, tank and anti-tank weapons do not pose a threat to the underground air raid shelters/shelters. The use of incendiary weapons (napalm and incendiary weapons) and FAE weapons also have no effect on the people in the shelter. [21]
Protection against secondary weapon effects
Protection against:
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Debris and splinters
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Fire hazard
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Water hazard
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Risk of slipping
When nuclear weapons are used or when attacks are carried out with conventional weapons, many buildings are destroyed in whole or in part. The resulting fragments and debris are thrown around like projectiles and pose a great danger to unprotected people.
The bunker/shelter can easily absorb the rubble load of collapsed buildings. In contrast to the air raid shelters of the Second World War, survival in this shelter is possible even if you are largely buried. In addition to the armored door, this shelter is also equipped with a special emergency exit for rescue from a burial.
Due to the design with a solid and tight protective cover, as well as the air intake from outside the building's floor plan, the room offers the necessary protection even in the event of a fire. [21]
Protection against biological weapons
Protection against:
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bacteria
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Viruses
When biological warfare agents are used, people, animals and plants are endangered or killed by pathogens via the air, water supply or food supply. The closed shelter prevents biological warfare agents from entering through the air. The introduction of pathogens can be prevented by having sufficient water and food supplies in the shelter. [21]
Protection against chemical weapons
Protection against:
Volatile warfare agents (aerosols and gases)
Sedentary warfare agents (liquids and solids)
Combinations of volatile and sedentary warfare agents
Even the smallest concentrations of chemical warfare agents can be fatal if exposed to unprotected conditions. It is therefore important to prevent the occupants of the shelter from coming into contact with the dangerous substances.
This is achieved in the shelter by the ventilation system, which cleans the poisoned supply air using a gas filter and creates a slight overpressure in the shelter itself. This overpressure prevents the ingress of poisoned outside air through any leaks in the shelter shell. [ 21 ]
Protection against reactor accidents and nuclear weapons
Protection against:
Mechanical weapon effect
Safe for a peak pressure of up to 100 kN/m² through air blast and pressure wave
Primary nuclear radiation
Totality of all direct and indirect ionizing radiation emanating from the mushroom cloud
Secondary nuclear radiation
Radioactive fallout, radioactive particle cloud
Electromagnetic effect
Destruction of electrical equipment
Thermal radiation
One third of the energy of a nuclear explosion is released as thermal radiation
Example Hiroshima:
Caliber of the nuclear weapon: approx. 12 kt, corresponding to an energy equivalent of 12,000 tons of conventional explosives.
At a distance of about 0.8 km from the drop point, people who were in such a shelter would have remained unharmed. People outside the shelter would have been seriously injured or killed. [21]
Detailed information on radioactive radiation can be found on our subpage:
How long can you survive in the shelter?
Use of shelters in different locations
Shelters are primarily designed for use in the event of an armed conflict. However, they are also suitable as emergency accommodation in other scenarios (eg a nuclear power plant accident or an earthquake). Shelters must be able to withstand the effects of modern weapons, ie they must primarily offer protection against ABC warfare agents and close-range hits from conventional weapons.
1) Peace phase
During this phase, the shelters are constructed. Appropriate maintenance and periodic shelter inspections ensure the permanent structural and technical readiness of the shelters. During the peace phase, the shelters are mostly used as cellars, storage rooms, hobby rooms, etc.
2) Pre-attack phase
During this phase, the shelters are prepared for rapid occupancy and, depending on the level of danger, are occupied as a precautionary measure, possibly in stages. Days or weeks can pass before the attack (or until the danger of an attack has subsided). During this time, limited communication with the outside world can take place, depending on the level of danger, with a temporary stay outside the shelter.
3) Attack phase
The attack phase is the period of time during which the weapon's actual effects on the shelter are felt. In the case of a nuclear weapon, these are thermal radiation, nuclear radiation, air blast and shock.
4) Post-attack phase
The post-attack phase is the period during which prolonged weapon effects or the consequences of weapon effects such as fires, debris, flooding, radioactive fallout, etc. do not allow anyone to leave the shelter. With regard to the duration of this phase, two areas can be clearly distinguished from the perspective of the dangers:
Short post-attack phase: This is likely to occur after nuclear attacks with an airborne blast point, after attacks with conventional weapons or after attacks with volatile chemical warfare agents.
Longer post-attack phase: This is particularly likely after a ground-level nuclear explosion. Depending on the intensity of the resulting radioactive fallout, a stay in a shelter for days or weeks is then necessary. A similar length of stay is also required in affected areas after the use of sedentary chemical warfare agents. In these cases, too, the shelter can often be left immediately after an attack, initially for a short period and later for a longer period.
5) Repair phase
The transition from the post-attack phase to the repair phase is usually gradual. The end of the post-attack phase is characterized primarily by the fact that the shelters can then be left without immediate danger from the effects of weapons. If the above-ground structures are destroyed on a large scale, the shelter continues to serve as accommodation during this phase.
Duration of stay in the shelter
The necessary length of stay in the shelter depends primarily on the type of threat and the supplies in the shelter.
In the case of a nuclear incident, according to the rule of seven, the radiation exposure has already decreased to about 1% of the original maximum reference dose after only two days. After 14 days, the radiation exposure remains at about 0.1%. [ 23 ]
In principle, the lower the effective radiation exposure, the longer the stay outside the shelter is possible .
Thus, after the radiation dose has subsided, the shelter can be left to obtain new supplies or to leave the area. [24]
Shelters and bunkers are designed to allow shorter or longer stays of several days and weeks. The length of stay in the shelter depends essentially on the food and water supplies.
Food and emergency supplies
Stocking of food and beverages
The possible length of stay in the shelter depends largely on the available supplies. However, there are also various emergency situations in which a supply of food and drinks is helpful. A large-scale power failure ("blackout") is enough for supermarkets, shops and petrol stations to remain closed. The power failure causes heating, lights, refrigerators and freezers to fail. Depending on regional conditions, drinking water will also no longer come out of the pipes.
The German Federal Office of Civil Protection and Disaster Assistance ( BBK ) therefore currently recommends stocking up on food for at least 10 days . [22] Food and drink supplies help bridge the time until government aid is available.
Tips for stockpiling from the German Federal Office of Civil Protection and Disaster Assistance (BBK)
Buy long-term food and build up supplies
Together with our cooperation partner krisenpakete.de, we offer well thought-out and up-to-date emergency preparedness.
Krisenpakete is your online store when it comes to quick and easy crisis preparedness. Whether you want to prepare for a blackout, natural disasters, looting, a chemical accident or a nuclear incident, you will find a targeted selection of products here.
We have put together special packages for shelters so that the shelters are equipped with the most important items.
We will be happy to answer any questions you may have on the subject of crisis prevention. We look forward to hearing from you.
