Article: Modern Blast Protection & Structural Reinforcement Solutions
Author: Andrey Shpak | LinkedIn >​
Civil Defense Standards and Building Norms/Regulations
When we are talking about the design of new protected facilities, buildings, civil defense shelters, or structures the protection elements are usually integrated already on the design stage and are supposed to include all features related to protection, life-support, safety, evacuation, and more.
There are different examples from countries like Finland, Israel, Switzerland, Singapore, and more where the Civil Defense Standards or Building Regulations give specific instructions for designing buildings that include protected areas. Naturally, the standards and norms in each country vary and there is currently no united standard because the threats, environmental conditions, and approaches to dealing with emergencies are unique. As far as I know, there is work done on the new ISO standard for the protection regulation but it will be more of general guidance and not a recommendation with specific practical solutions.
As an example, I would take two countries that have a local civil defense standard and tens of thousands of shelters in each of them. As we can find some similarities, there are also major differences between them. Let’s compare the key points to understand the differences in the design approach for shelters:
The main treats and differences in the design approach for shelters in Finland and Israel:
Upgrade the Protection of Standard Buildings and Facilities
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The majority of buildings in the world were not designed to provide any or provide minimal protection from threats like rocket or artillery attacks, terror attacks, as well as explosions created by industrial accidents or natural disasters, and today I would like to list several modern solutions from different manufacturers that can provide a significant protection upgrade to existing buildings and structures. In this list, I will refer only to the main threats and consideration factors of attack, blast, and related destructive effects.
Usually, when we design a solution, we have to take into consideration the following – explosion distance or is it a direct hit, blast wave force/duration (impulse), collateral damaging factors (heat, spall, and internal loose objects, etc.) along with other factors.
Main points:
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Structural integrity
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Walls/ceiling reinforcement
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Windows / doors / air supply openings protection
Structural integrity
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There are several ways to ensure structural integrity for a structure or building, but the most common way that is used today is the addition of an internal metal/composite frame that will provide additional reinforcement to existing walls/ceilings and ensure resistance to blast wave pressure effect, strength to the building against earthquake shocks, as well as provide protection in case of building collapse on top or side of the protected area.
Walls/ceiling reinforcement and protection level upgrade
There are several options for wall reinforcement that can be applied:
1. Composite or metal panels that can be attached to special frames or directly to the walls. Such a solution can be applied internally or externally depending on the threat level and its direction.
2. External screens or barriers as an additional layer of protection.
3. Special fabric liners / ballistic liners that are attached to the wall or ceiling and can improve ballistic protection, and prevent spall and wall parts from spreading into the protected area.
4. Expandable or fixed protective cabinets that are installed/placed inside rooms – can be opened inside and folded, if necessary, in several minutes or be placed constantly.
Doors and Hatches
We can divide the doors into 3 main categories that also can be sometimes combined:
1. Blast / ballistic doors – depending on the treat level, location of the door in the shelter as well as specific space claims different variants of the doors can be chosen. In different countries the is a standard that defines the opening sizes, protection levels, and even the structure of the door.
For example, Swiss doors have a metal frame that is filled with concrete to supply the same level of protection as the walls. In Finland, the SO-1 basic doors are made of thick metal plates and Israeli-made doors for private shelters are made with special inner structures covered by metal plates. In most of countries, Blast doors are also gastight to prevent contaminated air from entering the shelter and the demand is that after the blast the door will keep its gas tightness.
2. Gastight doors – doors with the main function of keeping the shelter sealed for preventing contamination to enter the protected area.
3. Fire doors – as their name these doors are used for protecting the internal space from fire outside usually for defined periods of time depending on the fire endurance rating (usually 20, 45, 60, 90, 180 minutes, and more).
Windows Protection (Blast / Ballistics)
As well, for windows there are several possible options for protection:
1. Blast-resistant and bulletproof windows for various levels of threats and conditions.
2. Special metal covers that are closed in case of emergencies and protect the windows from blast wave overpressure.
3. Retrofit/upgrade of standard windows with a special cable catch system and window films for preventing the window from flying inside and hearting people or damaging the equipment.
Protection for ventilation and service openings
Usually, shelters designed for a longer stay are equipped with air entrance and air exit openings that allow ventilation and air exchange. In case of a blast from outside the blast wave can enter the protected area. For protecting the air openings usually used blast valves or dampers that are normally open and allow air movement but in case of a blast, pressure prevents its entrance by closing mechanism.
