Advice on domestic shelters providing protection against nuclear explosions
A Home Office Guide
Domestic Nuclear Shelters
This booklet is a brief guide to three basic kinds of nuclear shelter:
Additional information about protection from nuclear
attack is to be found in the booklet Protect and Survive
available from Her Majestys Stationery Office and main
booksellers or by post from HMSO bookshops.
Light and heat
A nuclear explosion produces an intense flash of light lasting some seconds which would blind anyone seeing it. The heat flash can set fire to buildings up to some distance from the centre of the explosion depending upon the haziness of the atmosphere at the time. Skin exposed to the heat flash could suffer burns. But any shelter that withstands the blast would give protection against the heat flash. Any exposed parts of the shelter made of flammable material could catch fire. Exposed plastic would not catch fire hut might distort in the heat and this could weaken the resistance of the shelter to the subsequent blast wave.
Initial nuclear radiation (INR)
This very penetrating radiation is emitted from the fireball within one minute of the explosion. The distances from one megaton explosions and above, at which people require shielding from INR, are less than those distances at which there would be total destruction.
At the moment of explosion a blast wave would be generated, travelling at a tremendous speed and creating extremely strong winds which may last for several seconds. When the blast wave passes over a building the sudden increase of pressure and the following wind may cause the building either to explode or collapse.
The tremors or shock waves from a ground blast extend for a short distance only and would not affect buildings beyond those already destroyed by the blast. The effect on shelters below the ground would depend on their ability to withstand ground movement and on the nature of the soil. Depth in the ground, shape and flexibility would be important.
An explosion on or near the ground sucks up a large amount of earth and debris, which is vaporised as it rises to a great height and becomes high]y radioactive. It then condenses to sand-like particles which are carried along by the wind and drop to the ground. This fallout can come down very near to the explosion or may be carried by the wind for hundreds of miles. The fallout dust is usually visible to the naked eye, but it emits ionising radiation rather like X-rays, which cannot be seen or felt. Radiation is dangerous and heavy doses cause sickness or death. Fallout dust remains radioactive for some days after the explosion - and can, in certain circumstances, still he dangerous after several weeks.
Bombs exploding on or near the ground
When a nuclear weapon explodes on or near the ground, a shock like a small earthquake goes through the ground. The earth vaporised into the fireball leaves a crater around the site of the explosion. The vaporised earth falls to the ground from half an hour to up to about a day later as radioactive fallout.
Bombs exploding in the air
When a nuclear bomb explodes in the air the blast effect is more marked. The area affected will be about 30 per cent greater than a ground burst bomb of the same size. But with air-burst weapons there is no dangerous radioactive fallout - since the fireball does not touch the ground no earth is sucked up.
Fig 3 - The extent of blast, fire and INR effects
Air burst (1 megaton)
Ground burst (1 megaton)
|Limit of:||A||Total destruction||x||Approx. range of INR within which shielding is vital||z||Blistering to exposed skin|
|B||Irreparable damage||y||Fire zone|
Some relative protection values
|LEAD||0.5||STONE||2.2||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.|
|TILES||1.0 to 1.9||SAND||2.9|
|Blast Protection psi (pounds per square inch)||Up to 1.5||Up to 6||Up to 11||In excess of 11|
|Fallout Radiation Protection Factor||Not less than 40||Not less than 70||Not less than 200||In excess of 300. Also protects against INR|
|Distance from a one megaton air burst beyond which shelter will remain intact||7 miles||3 miles||2 miles||Closer than 2 miles depending on design|
|Ventilation||Natural||Natural or forced||Forced||Forced|
|Site of installation||In house or garden||In house||In
Sectional for access through house
|In garden. Appropriate access to garden necessary|
|Forethought and planning||Install
Some materials can be prepared in advance
|Obtain in peace-time. Install in crisis||Obtain
in peace-time. Install in peace time or crisis
(Can be installed as a permanent shelter)
|Install in peace-time using professional advice and help|
|Approximate expected cost (1980)||Nominal if using local materials: scaffold frame about £250||Kit
Plus any installation costs
|£6000-£10,000 (but more sophisticated designs would obviously cost more)|
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 rateable value of your home, and this is a matter for your local District Valuer and Valuation Officer (Regional Assessor in Scotland).
Easily-constructed improvised garden shelter using household materials
This shelter is suitable for areas where under ground
shelters are impracticable, for example, where there is a
high water table, so that a deep hole fills with water.
It can be constructed using only materials which are
generally available, and could be built in a time of
crisis. It would take two people about 24 working
hours each to build.
1. Select a site on level ground where there is little chance of rainwater collecting.
2. You will need:
3. Construct the shelter as shown in Figs 4-14.
4. Furnish the shelter as required.
40 in. by 2 in. temporary timber braces between doors.
Doors in position - construct temporary supporting
structure of doors and timber against which earth rolls
can be built (frame is removed later and doors, then used
to form a roof).
Fig 8 - Construction of earth rolls
Improvised outdoor shelter using do-it-yourself materials
The following diagrams show how a basic shelter can be
constructed from standard scaffold poles and other
materials available from builders merchants, timber yards
and do-it-yourself stores.
Prepare a trench 8 ft. x 8 ft. and at least 1 ft. 6 in. deep. Line it with heavy duty polythene sheeting. Lay a floor of two sheets of plywood, 3/4 in. thick and 4 ft. x 8 ft.
Construct the frame of scaffold poles (or you could use wood). This should be as strong as you can make it. You can increase the strength with vertical and diagonal bracing, or crossbars.
Add the frame for the entrance tunnel, and also the
ventilation pipe (described opposite).
Wrap the shelter with overlapping sheets of heavy duty polythene. Make sure the trench lining is within this cover.
Finally, cover the shelter with a thick layer of earth (about 18 in.). The earth removed from the trench may not be enough for this. It you decide to dig a deeper initial trench to get enough earth to cover, you may need to make some modifications to the design given here.
The shelter will give better blast protection if you
put a layer of resilient material between the polythene
and the earth covering. Straw, mattresses, or similar,
would be suitable.
For this shelter you will need to make some provision for ventilation. The diagrams show metal drainpipes with a bend near the opening, so that this faces downward. The opening should then be filled with a filter of steel wool. It is extremely important to ensure that ventilation pipes are secure and kept free of obstruction.
Indoor shelter from manufactured kit
This type of shelter - basically a protective steel
table - is suitable for homes that have basements or
rooms that can be converted into 'fallout rooms' (described
in Protect and Survive) provided that the floor is strong
enough to support it.
Outdoor shelter from a manufactured kit
This type of shelter is generally suitable where there
is a garden or other convenient land near the living
accommodation. It is formed by building a strong
structural shell with prefabricated steel components
bolted together to form a sealed room of sufficient size
for up to six people. The shell is semi-sunk in the
ground and covered entirely by earth from the excavation.
Permanent purpose-built shelter
This reinforced concrete shelter must be erected by a
building contractor under the guidance of a chartered
civil/structural engineer. It should on no account be
erected by unskilled or unsupervised labour.
Life in the confined space of a survival shelter needs careful planning.
You should store as much as possible of the following in your shelter:
Water in sealed or covered containers to last you and your family for 14 days. Four pints per person per day would be sufficient for drinking and basic cleanliness.
Enough food for 14 days, including tinned or powdered
milk for the children and food for the baby - and a
closed cupboard or cabinet in which to store these
A portable radio (and a spare if possible) and spare
Tin opener, bottle opener, cutlery, crockery and cooking utensils.
Warm clothing and footwear and changes of clothing.
Bedding. sleeping bags, etc.
Torches with spare bulbs and batteries, candles and matches. Open flames should not be used in shelter types 3 and 4 until the shelter door can be opened.
Toilet articles and washbowls.
First aid kit.
Notebooks and pencils for noting radio instructions.
Cleaning materials: including cloths, tissues, brushes, shovels and box of dry sand.
Improvised lavatory seat, polythene buckets fitted with covers, polythene bag linings for emptying the contents, strong disinfectant and toilet paper. Alternatively camping or caravan type toilet arrangements may be used.
Clock and calendar.
and just outside your shelter
Dustbin for temporary storage of waste matter.
Second dustbin for food remains. empty tins and other rubbish.
Polythene bag or bin for outdoor clothes and boots.
If possible. extra water supplies in covered containers, and games, children's toys and books.
Stoves burning liquid fuel or gas may be used at or just outside the entrance of shelter types 1, 1a and 2, or in a similar way in types lb, 3 and 4 but only when it is safe to open the hatch or door. Otherwise you should not use a stove of this kind in a sealed shelter.
Suggested food list
Supplies for two weeks for one adult
|Biscuits, crackers, breakfast cereals etc.||2750g (6 lb)*|
|Canned meat or fish (e.g. corned beef, luncheon meat, stewed steak, pilchards, sardines)||2000g (4¼ lb)|
|Canned vegetables (e.g. baked beans, carrots, potatoes, sweetcorn etc.)||1800g (4 lb)|
|Canned margarine or butter, or peanut butter||500g (1 lb)|
|Jam, marmalade, honey or spread||500g (1 lb)|
|Canned soups||6 cans|
|Full cream evaporated milk or dried milk||14 small cans or 2 x 300g(1/2 lb) containers|
|Sugar||700g (1 1/2 lb)|
|Tea or coffee (instant)||250g (1/2 lb)|
|Boiled sweets or other sweets||450g (1 lb)|
|Canned fruit, fruit juices, fruit squash, drinking chocolate||If sufficient storage space is available|
|Approximate cost (mid 1980)||£15-£20|
|* Imperial equivalents are only approximate.|
|This list is based on the assumption that cooking will not be possible and that the opportunities for warming foods or boiling water may be limited. For further details see Domestic Nuclear Shelters - Technical Guidance.|
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Last updated June 1999
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