nuclear.shelter

Domestic Nuclear Shelters

On this site you will find a brief guide to three basic kinds of nuclear shelter:

What happens to fallout after a nuclear attack

It is important to understand that radiation emitted from fallout decreases quickly at first and then more slowly over time. For example, after 7 hours, the radiation emitted will be only 10% of its original strength, and after 2 days, it will be only 1% of its original strength.

When the radiation levels have decreased to a safe level, you will be informed that it is safe to leave your shelter for short periods of time. Initially, it might only be safe to spend an hour or so outside per day, but over time, this safe period will increase until it becomes safe to stay outside all the time. Even in the most severely affected areas, it might be safe to leave the shelter entirely after about two weeks, while in most places, this period would be much shorter.

When you are outside of the shelter, you do not need special clothing, but it is advisable to wear outdoor clothing and wellington boots or sturdy shoes to avoid contaminating your indoor clothing. It is also important to remove these clothes before re-entering the shelter.

Shelters offer different levels of protection against blast and fallout. They also provide protection against the heat flash provided that no flammable materials are exposed. However, no shelter can protect someone close to the site of a nuclear explosion. The principal danger after the explosion is from radioactive fallout.

Dense material around a shelter will lessen the risk of harm from radiation as long as you remain inside. Generally, the thicker the material, the better the protection, but some protective materials are more effective than others. Below is a list of common materials likely to be used in the construction of a shelter, along with their value as protection against radiation given in terms of the thickness required to reduce radiation by one half. For example, 2 inches of lead provides the same protection as 3.5 inches of slate.

The protection given by buildings or shelters can be expressed as a protective factor. A typical house will reduce the power of radiation to one fifteenth of that outside, which is called a protective factor of 15. Shelters constructed of the right materials can give a much greater protective factor than this.

Some relative protection values

Increased thicknesses of material reduce the intensity of ionising radiation. For example, each 2.2 in. of concrete reduces the intensity by half, so a thickness of 8.8 in. of concrete would reduce the radiation to one sixteenth of its original intensity.

The overall picture

If there were a nuclear attack, it is likely that some bombs would burst in the air and some on or near the ground. Estimates suggest that around 5% of the land area in the UK may be severely affected by the blast. However, it is impossible to predict where the bombs would fall. About 80% of the land area may not be affected by blast effects at all. 

Since any part of the country might suffer fallout, radiation protection would be required everywhere.

Types of shelters

On this page you can find information about four different types of shelters, including their protective features and suggested locations. These examples are based on the designs presented in the publication "Domestic Nuclear Shelters - Technical Guidance" - a publication by the UK government that provides detailed instructions for constructing nuclear shelters.  While it may be possible to modify the materials or construction methods shown here without compromising the level of protection, it's important to ensure that any changes still meet the guidance provided here and in that publication. If you plan to consult with a professional regarding building a shelter, it's recommended to choose someone who is qualified in the field, preferably an architect or chartered civil/structural engineer.

Planning permission, Building Regulations and rating

If you wish to install a permanent shelter you may need permission. You should check the regulations before submitting plans or beginning work. Your local District Council will tell you about planning permission and the Building Regulations. 

A permanent shelter may affect the value of your home, and this is a matter for your local District Valuer and Valuation Officer.

Type 1a shelter

Easily-constructed improvised garden shelter using household materials

Perfect for regions where digging underground shelters is tricky, like places with high water tables, this simple garden shelter is a practical solution. You can put this together using materials commonly found around your home, and it's a project you could tackle during a crisis. With two people working, it should take about 24 working hours to complete.

The shelter involves digging a shallow trench into the ground, topped with a roof made from doors or sheet timber. The roof is supported above ground by walls of earth, and the entire structure gets covered with at least 18 inches of earth.

This straightforward design provides effective protection from fallout radiation, especially if occupants stay away from the entrance area. For added safety, consider constructing a barrier of sandbags or packed soil about two feet in front of the entrance, reaching the same height. This extra step significantly enhances protection in the entrance area.

Materials and Construction Steps


How To Build Shelter In Your Backyard using Household Materials

Step 1: Mark out the trench

Step 2: Excavate trench


Step 3: Construct temporary walls

Install temporary timber braces measuring 40 inches by 2 inches between the doors. Once the doors are in position, create a temporary supporting structure using doors and timber.

This structure will serve as a foundation against which earth rolls can be constructed. The frame is later removed, and the doors are repurposed to form a roof.



Step 4: Position sheeting materials



Step 5: Construction of earth rolls



Step 6: Remove temporary walls



Step 6: Construct door frames



Step 7: Use sandbags for support



Step 8: Construction of earth rolls



Step 9: Position doors and waterproof cover



Step 10: Finish bunker with earth cover



Type 1B Shelter

Improvised outdoor shelter using DIY materials

Building an improvised outdoor shelter with do-it-yourself materials is an efficient and adaptable solution. The diagrams below illustrate how to construct a basic shelter using standard scaffold poles and readily available materials from builders' merchants, timber yards, and do-it-yourself stores. This type of shelter is designed to be built from previously purchased and stored materials, making it a feasible project during a crisis. The construction, requiring approximately 24 working hours for two people, can be adapted in size to suit different needs.

How To Build Shelter In Your Garden using DIY Materials

Step 1: Prepare the Ground

Dig a trench measuring 8 ft. x 8 ft. and at least 1 ft. 6 in. deep. Line it with heavy-duty polythene sheeting.

Step 2: Create the Floor

Lay a floor of two sheets of 3/4-inch thick plywood, each measuring 4 ft. x 8 ft.

Step 3: Build the Scaffold Frame

Construct a robust frame using steel or alloy scaffold poles arranged in 'A' frames over the trench. Brace the frames diagonally along their length and across the waists of the 'A' sections for rigidity, using proprietary clamps for secure connections.

Step 4: Add Entrance Tunnel and Ventilation

Incorporate a frame for the entrance tunnel and a ventilation pipe. Ensure the frame is as strong as possible, considering additional vertical and diagonal bracing or crossbars.

Step 5: Board the Frame

Cover the entire frame (excluding the entrance hole) with plywood boarding. Use carpet or thick fabric to cover any small gaps or sharp edges.

Step 6: Wrap with Polythene

Wrap the shelter with overlapping sheets of heavy-duty polythene, ensuring the trench lining is within this cover.

Step 7: Cover with Earth

Cover the shelter with a thick layer of earth (about 18 in.). Consider adding a layer of resilient material, such as straw or mattresses, between the polythene and the earth for better blast protection.

Step 8: Ventilation

Install ventilation using metal drainpipes with a downward-facing bend near the opening. Fill the opening with a filter of steel wool. Ensure the ventilation pipes remain secure and free of obstruction.

Important Note

The entrance can be filled from within with small bags of sand or earth, which should be stored inside the shelter.

These designs are intended for use in crisis situations, providing efficient and adaptable shelters that can be constructed using accessible materials. For additional guidance and specific design drawings, refer to "Domestic Nuclear Shelters - Technical Guidance."