Utah Shelter Systems - Because Survival Is The Highest Priority

About Our NBC Shelters



© 1987 - 2014 Utah Shelters Inc. All rights reserved.


Protection from gamma radiation can be achieved with as little as 4 feet of dirt cover or 3 feet of concrete cover.  Every 4 inches of dirt (and 3 inches of concrete) gives a halving thickness, or protection factor (PF) of 2.  Ten halving thickness is required to diminish (attenuate) medium to high levels of radiation to an acceptable level. 

Six to 8 feet of dirt cover is required to attenuate initial radiation to acceptable levels.  Initial radiation occurs within the first minute of the blast and within a 1-½ mile radius of ground zero.  Blast damage is also an issue at that range.   All Utah Shelter Systems shelters are designed to withstand gamma and initial radiation, as well as high blasts in the initial radiation zone.

Entrance doors are not thick enough to attenuate radiation to acceptable levels, and most of the radiation will enter the shelter through the entrances.  Utah Shelter Systems has designed their entrances to attenuate gamma by providing a 90-degree turn, and long vertical and horizontal runs.  The initial radiation must be attenuated with six feet of shielding placed into the horizontal run.

For further information on Radiation, see Weapons Effects.



Utah Shelter Systems specializes in manufacturing steel shelters because they offer very cost effective protection from the effects of nuclear weapons, as well as biological and chemical weapons (NBC).  That ordinary citizens can be so effectively protected to within 1/2 mile of a large yield nuclear explosion for about the cost of a new pickup truck is remarkable.  The concept is simple.  A steel cylinder of a usable size is outfitted with bulkheads, a deck, electrical system, ventilation system, and properly designed   entrances, and buried to a suitable depth to ensure proper earth arching and shielding.  If the wall thickness of the cylinder is thick enough, and the backfill is performed to industry specifications, such a structure will endure a nuclear shock that would destroy all above ground buildings within a 5 mile radius of the blast.

Corrugated steel shelters were tested and proven at the Nevada test site to blast pressures of 200 psi. In order to achieve protection to that level, the shelter must have an arched ceiling and the dirt cover over the shelter chamber must be equal to or greater than the diameter of the shelter.   At this depth, ‘earth arching’ is achieved.  Care must be taken to properly match the gauge of the steel to the shelter diameter.   We design all shelters to this protection level.  Eight-foot shelters are built of the proper gauge to be placed into a 16-foot hole and to safely withstand the burden of 8 feet of dirt cover plus the additional overpressure of 200 pounds per square inch of air blast.  Nine-foot shelters can safely be installed into an 18-foot hole.  Ten-foot shelters are designed to be placed into a 20-foot hole with 10 feet of cover.  Flat roofed steel shelters will not withstand these heavy burdens.   They will fail catastrophically under these overpressure loads.


Steel shelters make a natural ‘faraday’ cage and will protect all electrical equipment inside the shelter IF there are no antennas or other electrical wires entering the structure.  Every incoming wire potentially offers entrance of the electro magnetic pulse (EMP).   

In our own personal shelters, we protect all critical radios and other vulnerable equipment in faraday cages to assure their survival.  We make simple, inexpensive faraday cages from steel garbage cans.  We wrap our equipment in soft towels or place them in cardboard boxes before placing them into the cage.  We do not ground this can.

For further information on EMP, see Weapons Effects



‘All Hazard’ Shelters must be protected against the intrusion from chemical/biological war gasses.  Gas tight doors and blast valves provide a slightly positive air pressure, as outside air enters the shelter and is filtered though the gas filter.   This positive pressure holds un-filtered air from intruding into the shelter.  This filtration process is standard with all shelters from Utah Shelter Systems. 

People requiring tornado and hurricane shelters, only, may wish to purchase the ventilator without the addition of the gas filter.  Call us for pricing on this option.

Some people wish to have an ‘air lock’ option.  An air lock is a preliminary room used for entering and exiting the main shelter without contaminating the shelter room with outside air.  See the section marked AIR LOCKS for design information.           

See About Our Chem/Bio Filters for more information on chemical/biological issues.



All shelters should have two entrances to assure egress in the event one entrance is blocked by debris.  All entrances must be protected with steel blast doors.

Most all of the radiation entering the shelter will enter though the entrances. Distance and geometry play an extremely important role in the attenuation of radiation.

It is mandatory that nuclear shelter entrances have both a vertical and horizontal component, connected with a 90-degree turn.  To properly attenuate gamma radiation, the total entrance length must be at least 4 times the diameter, with the vertical and horizontal legs as close to the same size as possible. 

Gamma radiation is a factor during the first two weeks after a nuclear event.  Gamma radiation is directional and will not ‘corner’ well.  The 90-degree turn between the vertical and horizontal run will attenuate 90% of the gamma radiation and the horizontal run will reduce the remaining radiation to a small fraction. Large diameter entrances are very comfortable and convenient, but they require long runs and are not practical in the attenuation of initial radiation.

Initial radiation is more penetrating than gamma radiation.  It is a factor during the first minutes of the explosion, and affects all the area within 1-½ miles of the blast. People sheltering within that area will have lethal levels of initial radiation if they do not properly shield against this effect. The vertical and horizontal runs should each be between 10 and 12 feet long, and the diameter of the entrance should not exceed 48”. Initial radiation is not significantly attenuated by 90- degree turns.  The horizontal run of the entrance, therefore, should be filled with shielding materials after the occupants have entered the shelter.  Water, rice or any other material containing large amounts of hydrogen make good shields against initial radiation.    These principles must not be compromised!  Larger diameter entrances are comfortable and convenient, but the occupants may not survive if they are within the 1-½ mile zone.



Entrances may be put into buildings such as the home, garage or outbuildings.  However, to protect against debris or fire, always place one entrance into the yard, exterior to the building.

Entrances may be placed on either the ends or the sides of the shelter.  Side entrances free the interior flat ends for furniture or bathroom use.  However, when figuring transport costs, a side entrance increases the overall width and will possibly increase the transport cost.



Lighting is provided with both an AC and DC wiring system.   Miniature 12-volt lights are are placed every 8 feet along a ceiling unistrut.  These lights use a standard bayonet base and may be replaced from stock found at Radio Shack.  These lights are protected against blast by their installation on a sturdy wire, which hangs a couple of inches below the unistrut.  During a disaster, we plan to keep one (and only one) of these miniature lights turned on at all times.  As a note, LED lights may be used to replace the standard lights in the shelter.  They are, however, expensive and may be vulnerable to the EMP effect.  LEDs should be stored in a Faraday cage until after all threat of an EMP has passed.  

During peacetime, we use the 12-volt fluorescent lighting system that comes with the shelter.  We also have access to AC receptacles that have been placed every 8 feet along the ceiling unistrut, and can uses them for plug in type lamps if we desire.


We often speak of the scenario of experiencing a large earthquake in the middle of the night, and in the middle of the winter.  At near or below zero temperatures, if unprepared, few people would survive the night.  Our shelters would withstand a huge earthquake and all associated after shocks.  We have beds, food, water, light, communications, clothing and supplies ready in our shelters at all times.   We could just go to our shelters, go to bed, and deal with the earthquake in the morning!  

Shelters with 7 to 10 feet of dirt cover, remain at a constant temperature between 45 F. and 65 F.   Our shelters installed in the mountains of Utah, in below 0 Fahrenheit weather, never go below 45-degrees Fahrenheit.  In the winter we wear lightweight jackets or sweat shirts and feel very comfortable.  As occupants enter the shelter, the temperature will rise.  Every person radiates as much heat as a 100-watt light bulb.  The steel walls of the shelter act as a heat sink, and keep the shelter from becoming too warm.  We highly recommend that NO insulation be placed on the walls or ceiling of steel shelters.  No outside source of heat is needed.  In peacetime, if fuel and power are not an issue, the shelters can be heated with an electric space heater. 




We highly recommend using a 12-volt system over the 48-volt system.  The 48-volt systems are very expensive and replete with problems.  The 12-volt chargers and inverters are reasonably priced and very dependable.  

Batteries do not come standard with our shelters.  Everyone seems to have their own electrical preferences.  All of our shelters, however, come wired for both a 12-volt DC and a 110-volt AC system.  We would be happy, however, to direct you to good sources for batteries and supporting equipment.  We have used a number of different batteries in our shelter systems.  The two we prefer are the 6-volt golf cart batteries and the 6-volt 'gel-cell' batteries. Car batteries should not be used in shelters, as they have a totally different function.

Our first preference is the 6-volt gel-cell battery.  Two of these batteries wired for 12 volts are rated at 180 amp hours or 2160-Watts hours.  We recommend having no fewer than eight of the 6-volt batteries to run your shelter. In our experience, we have found that gel-cell batteries can be charged many more times with excellent recovery than can deep-cycle lead-acid batteries.  They are two to three times more expensive, however they do not outgas and they have a much longer life expectancy.  Gel-cell batteries require a special charger.  We like the IOTA DLS 55 or DLS 75 charger.   

We have prepared our own personal shelters to run on battery power for at least 3 weeks, before needing to recharge.  After that period of time, we plan to recharge the batteries with a small generator or other alternate power system.  Solar panels are vulnerable to EMP, and may fail if left out during wartime.

Solar Panels:

Solar panels may be used to recharge the batteries, but when not in use they should be stored inside the shelter for maximum protection from blast and EMP. They should be placed outside only after all danger of blast has passed. They may be adversely affected by the EMP. If in a remote area, consider putting out a ‘sacrificial’ panel and purchasing extra solar panels for later. Store these panels wrapped in aluminum foil, for 'EMP' protection, and keep them inside your shelter until use.

In remote areas, we use our ‘sacrificial’ solar panels to keep a charge on our batteries at all times.  We know an EMP would most probably destroy the panels, but it is worth the sacrifice to have charged batteries when we arrive at the site.  We usually run one 30-watt panel at a time.  We keep several more solar panels inside the steel shelter to protect them from the EMP.

Don't spend your amp hours unwisely.  Hand-pump your air system and eat pre-cooked foods.  Wear warm clothing and think only, ‘basic survival’.  Your battery power should be used only for lighting and radio communication. 

It should be obvious, how important the battery system is.  Take care of them and keep them charged on a regular basis.  It would be catastrophic to enter your shelter in an emergency, with uncharged or damaged batteries.


We prefer diesel generators to gasoline or propane.  Diesel fuel stores very well, if a stabilizer is added each year.  We never store propane or gasoline in an underground generator room.  A small generator can be stored in your shelter room, but must be taken outside to run it.

We recommend the purchase of a diesel generator at (or smaller) than 2kW, for battery charging.  Large generators are great for running a house, but the fuel will not be readily available after large-scale emergencies such as full scale EMP or full-scale nuclear war.  The exception to the large generator rule is if you need to run a motor in a deep well.

Mechron Power Systems (613-733-3855) sells a 2kW Portable military, brush type diesel Generator. It has very low fuel consumption, running on about 1 pint per hour.   Brush type generators are less vulnerable to an  EMP. 

Energy Management (801-366-4100) has brush type generators available in 8 kW, 10kW and 15 kW sizes.   You may wish to purchase an extra voltage regulator, as it will be EMP vulnerable. 



Outside information is critical for your survival in a disaster.  Plan to have several forms of communication.  We suggest that you purchase a good short wave radio, CB radio, and if possible, an amateur radio in the 40 to 80 meter band area.  CBs are useful at short distances and are ‘line of site’, only; but they will provide local information, which may be very important.  The usefulness of two -meter radios is limited after a nuclear attack, because the EMP will destroy relay stations needed for two-meter transmission and reception, even though the radio itself, may have survived the event.  Two meter radios, though much more expensive than CBs, will have the same resulting range. Amateur radios in the 40 to 80 meter range, on the other hand, will continue to function (if protected during the actual EMP event) because relay stations are not needed for their use.  

We highly encourage at least one of the people assigned to your shelter, to become a licensed amateur radio operator.  Form nets using similar maps, and practice disaster scenarios.

Though protected, radios may not function for a few hours to days because of disturbances in the ionosphere.  After two full days, turn on and listen to your radio for short periods of time.  It is psychology imperative that you have outside contact.  Plan to use your CB or ham radio sparingly, as transmitting on these radios requires a great deal more power than when they are in the ‘receiving’ mode.  If others that you know have shelters, plan to use the same frequencies.

CB and Amateur Radio



In areas believed to be more than 3 miles from a prime target, various items of furniture can be added to the shelters.  All shelters come standard with two sets of double bunks and two sets of single sitting bunks. The bunks add a great deal of comfort and a higher quality of rest. When maximizing occupancy, sleeping should be done in shifts, and each bunk used by a different person for 8 hours during the day.   All bunks have hinged tops, providing room for tidy storage of personal items or supplies. The sitting bunks face one another and provide room for a fold-up table to slip underneath, out of site. Tables are convenient and provide a more normal atmosphere to the living space for eating and socializing.

If outside the 3-mile heavy blast range, you may wish to have us add storage shelves, bathroom (including toilet, sink and gray-water drain); and a kitchen (with stainless steel sink, plumbing, 12 volt water pump, Formica countertop, and cabinets).

In areas of high blast potential, keep furniture to a minimum.  Use hammocks for sleeping and secure all items to the wall.  You may want to substitute two additional lengths of unistrut on the wall, for your standard bunks.  The unistrut would then be used to tie-down and secure equipment and supplies.

All shelters come standard with ladders for each of the two entrances.  During installation, the 48-inch diameter entrance should be tilted to a 60 degree angle.  The step ladder is designed to that angle.  The 36 inch diameter exit tunnel is designed for a vertical configuration to facilitate the lowering of supplies by a rope or small crane.  The center floor panels are removable in 4 ft. lengths, down the entire length of the shelter.  This provides easy access to supplies and keeps the shelter free of clutter.  





Ten-foot diameter shelters provide three feet of under floor (basement) storage space.  This is triple the amount provided in an eight foot diameter shelter.  Nine foot diameter shelters have 2 feet of basement space, and 8 ft. diameter shelters provide one foot of under- floor storage.  Ceiling space remains constant in 8, 9 and 10 foot diameter shelters, with a center height of 7 feet.

Storage under hinged bunk seats is provided in every shelter unless otherwise requested.  Battery storage areas can be constructed upon request.  Radio shelves (upon request) fit nicely on the bulkhead, next to the ventilator. 

Ten-foot diameter shelters provide the most economical use of living and storage space for dollars spent.


We recommend storing a one year’s supply of food and 55 gallons of water per person.  Water can be stored in 30-gallon barrels, under the floor of 10-foot diameter shelters or in 55 gallon barrels on top of the floor in all sizes of shelters.  Water can also be stored under the floor in water bladders that form to the curvature of the tank, in any diameter shelter. 

Water tanks can be buried outside with a hose attached to provide gravity flow into the shelter.  These tanks must be covered with dirt at a depth that is double the diameter of the water tank. Water tanks at or near the surface are vulnerable to ‘ground slap’ from blast and mischief from intruders.

Large water tanks and water bladders (inside or outside) pose the risk that you may lose your entire supply in the event the containers form a leak.  We prefer to use 30 and 50 gallon barrels for water storage; and in our personal shelters, we always store our water inside our shelters. 


Ten-foot diameter shelters provide three feet of under floor (basement) storage space.  This is triple the amount provided in an eight foot diameter shelter.  Nine foot diameter shelters have 2 feet of basement space, and 8 ft. diameter shelters provide one foot of under- floor storage.  Ceiling space remains constant in 8, 9 and 10 foot diameter shelters, with a center height of 7 feet.

Storage under hinged bunk seats is provided in every shelter unless otherwise requested.  Battery storage areas can be constructed upon request.  Radio shelves (upon request) fit nicely on the bulkhead, next to the ventilator. 

Ten-foot diameter shelters provide the most economical use of living and storage space for dollars spent.


During peacetime we cook in microwave ovens or on electric burners.  We never use propane or gas in our shelters for the following two reasons.  First, propane is heavier than air and if there is a leak, it could accumulate under the floor where it will pose an ignition problem. Secondly, the burning of fossil fuels, such as propane or gas, produces significant amounts of carbon monoxide.

During emergency operation, we do not use battery or electric power to cook.  The preferred method of cooking during that time is via marine alcohol stoves.  Unlike propane or gas, when alcohol burns it produces only carbon dioxide and water.  Of course, any flame consumes oxygen and requires good ventilation. Alcohol fuel can be purchased at most any hardware or marine store. It is not explosive, but must be carefully stored, as it will act as an accelerant in the event of a fire.



Holding tanks and septic tanks are acceptable in areas of low or no blast and areas of no threat of chemical/biological war gasses.  The tanks, however, are extremely vulnerable to ground slap from blast, and may crack or rupture during earthquakes.  Flying debris from high winds during tornados, hurricanes or blast could break the lids of these tanks, and if they are at or near the surface the contents will be forced back into the shelter.  We do not install flush toilets.

We prefer (and install) the most simple of solutions for bathroom facilities- chemical toilets- for the following reasons:

  • Flush toilets require large amounts of water.  Water is at a premium.
  • Flush toilets require vents, which must have blast valves to protect the positive pressure within your shelter for protection from war gasses.
  • Holding tanks cannot be emptied after a large-scale emergency.
  • Septic tanks are vulnerable to blast and earth movement.

Use separate toilets for solid waste and urine.  Cover solid waste with a disinfectant solution or kitty litter.  Solid waste should be stored in barrels in double plastic bags, until it is safe to remove and bury it outside.  Urine can be poured into the gray-water drain.

In the event of a nuclear or biological attack, you may not be able to return to your home to live.   Bacterial agents may enter your above ground home through broken windows and the furnace ducting system.  Sunlight will destroy bacteria that are on the ground, but it cannot reach inside your ducting system to destroy these agents.   If your home is damaged or destroyed and you are forced to continue to live in your shelter, construct an old-fashioned ‘outhouse’ downhill from your shelter.

© 1987 - 2014 Utah Shelters Inc. All rights reserved.