Click on Images below for a better view of vault layouts and design configurations.
Steel and Concrete Vaults may be installed above Ground or Below Ground. In many cases structures are below a house, or next to it underground, with access to it from the house itself or a secure door located just outside, located in a concrete slab.
The ceiling of the shelter is made of thick reinforced concrete and steel which, in the event of the house collapsing, a severe storm or fire should support the load and be fire resistant enough to avoid being affected. Multiple access is a consideration on larger below ground shelters.
There are above-ground, below-ground, dedicated, dual-purpose, and potential vault designs. Dedicated blast shelters are built specifically for the purpose of blast protection.
Dual-purpose blast shelters are existing structures with blast protective properties that have been modified to accommodate people in their seeking protection from a blast or fallout.
Generally, fallout shelters are much deeper than typical storm shelters.The basic plan is to provide a structure that is very strong in compression and fire resistant. The actual strength specification must be done individually, based on the nature and probability of the threat.
It is safe to say if a shelter has a covering of 14" or more of soil and is built of concrete with reinforced steel with a ceiling thicknessof 12" or so of concrete would be considered 'safe' for most security considerations. Adequate venting is a priority for a below ground structure.
"A below ground vault may be located below a house in new construction homes. Door and stairwell entry would be located so after the house is built entry would be in a closet or a hidden room. A special hidden door may be used, then one may go down stairwell into the shelter via a secure safe room door."
A secret passage, hidden door or a secret tunnel may be inside a home or building leading to a secure room located below or just outside underground. Hidden passages are a common feature of fiction, but have also served a variety of purposes throughout history. Hidden Rooms have helped people evade capture or carry out illegal religious, political, or smuggling activities.
