Key Features


composite-structure_tm The C3 vacuum infused carbon fiber composite is resilient and durable unlike other shelters. Radius Shelters have no basement feeling, no tin can feeling, and not a retrofitted tank. Our structures are designed as high pressure composite underground structures. Radius shelters have a life span of over 250 years, no corrosion inside or outside, no condensation inside the shelter like steel tanks, and the shelter inside surface is always bright white.


design_tmRadius shelters are compound curved shapes with no catastrophic failure mode like round flat or corrugated culverts.  Radius shelters have no flat walls and no tensile loads.  Radius shelters are specifically designed for external pressures and ground shock far exceeding 8.5 Richter and can be placed in high water tables without tie-downs to produce concentrated stresses. The sealed composite shell keeps out radon gas as well as bugs and water.


com_prod_tmRadius Engineering International Inc. is a United States Department of Defense Contractor and our products are ITAR (International Trade Arms Regulated) and listed on the USML (United States Munitions List). Things that defend against a weapon system are classified the same as the weapon system.


constant_hull_tmRadius Shelters have a constant pressure rating that does not have to be de-rated each year due to corrosion like steel structures. The walls of all Radius shelters are designed with an outward curve making the structure extremely strong and providing a much better atmosphere for claustrophobic shelterists. Radius shelters range in rating from 10 psi (2 miles from Ground Zero of a 1 MT nuclear weapon) to 40 psi (1 mile from GZ of a 1 MT nuclear weapon) external pressure in addition to the earth static load and does not depend on earth arching. Shelters exposed to more than 40 psi require seatbelts.


rad_shield_tmRadius shelters have angled entranceways to reduce radiation entering the shelter to a safe level. All entranceway radiation transport geometry complies with PRINCIPLES OF PROTECTION , The US Handbook of Shelter Design Engineering Standards, 6th edition 2012. The earth cover over all Radius shelters ranges from 6 ft to 8.5 ft. The maximum radiation dose in any Radius shelter through both the entranceway and from overhead is based on a 1 MT surface burst and a 500 KT air burst which results in a maximum lifetime radiation dose inside the shelter from initial gamma radiation, gamma radiation, and neutron radiation of less than 1 REM (The same as a chest X-Ray).


stealth_tmRadius composite structures have no radar signature, minimal thermal signature, and with 8.5′ of earth over the ceiling it is hard to find with ground penetrating radar. Camouflage and landscaping limit detection by digital imagery systems and direct observation.


Radius shelters are entered by conventional stairwells, spiral stairwells, ramps for the handicapped, tunnel ramps for vehicles, and various emergency escape tunnels.

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jointsAll connections from entranceways to the shelter and between shelters have a seismic joints allowing flexing during ground shock and normal earth movement.


internalshelterRadius shelters use blast valves on the air inlet and outlet to maintain normal pressure during the overpressure and suction phase of a blast.   Overpressure choking is also used as a redundant system. internal-pressure-graph


empRadius Shelters do not rely the shelter hull to shield equipment inside the shelter from EMP and therefore does not rely on EMP sealing of or Points Of Entry (POE,s) into the hull like air pipes, electrical lines, water hoses, entranceway, escape tunnels, hatches, etc. To meet MIL MIL-STD-188-125-1:” High Altitude Electromagnetic Pulse (HEMP)  Protection for Ground-Based C4I Facilities Performing Critical, Time-Urgent  Missions Part 1: Fixed Facilities” 17 July 1998, all mission essential equipment (MEE) vulnerable to EMP is mounted in a tested EMP shielded enclosure meeting QQ-A-200/8, MIL-C-7438, MIL-T-10727, and Shielding Minimums of MIL-188-125.


Radius has a 35 year shelter engineering and manufacturing history which started with concrete and steel shelters and over a period of years evolved to composite high pressure structures as the market demanded better performance for underground structures.

shelterhistory1 shelterhistory2 shelterhistory3 shelterhistory4 shelterhistory5


food_storageRadius Shelters can be supplied with optional Food Storage Beams that are extremely efficient and store large amounts of food under the second or third story floor and also provide a structural clear span beam. Space within walls and other structural elements can also be used for storage.


airfiltrationRadius shelters use a patented Nuclear-Biological-Radius shelters use a patented Nuclear-Biological-Chemical air filtration process called MCAS. The Multiple Chamber Air Sterilization filtration system is composed of a HEPA filter, activated carbon filter, TEDA carbon filter, and Ultraviolet Sterilization chamber producing a kill rate many times that required to kill molds, bacteria, and viruses. Air volumes range from 60 to 600 cfm depending on the blower. The filter elements are visible and can be easily changed and chemical warfare agents can be detected with this system without exiting the shelter. The Radius MCAS air filtration system supplies filtered breathing air for people and for the generator at a minimum of 10 cubic feet per minute per shelterist. The normal breathing rate for an adults human is 0.33 cfm (cubic feet per minute).


Radius shelters have internal quiet diesel or propane generators providing power for 6 months to 5 years off the local power grid. Diesel tanks are made of special structural fiberglass located inside the shelter for leak detection and propane tank are external underground tanks. Fungicides and circulating pumps maintain the diesel fuel. All air entering the shelter is filtered including generator cooling and combustion air. Generator exhaust is mixed with cooling air and diffused over a large area at the surface to minimize the thermal signature. The generators is shown here without the EMP shielded enclosure.




Secrecy is essential to prevent from having to defend the shelter from intruders after a disaster and worse intruders may get to the shelter before the members if the location is known. Radius Shelters are temporary emergency structures having no foundation and no connection to local services therefore building permits are not required (Permits are posted for public inspection). Earthcom structures have no concrete foundations or slab so there is no cure time installing a shelter. No local contractors are used for the installation. Under the Second Amendment of the United States Constitution, US citizens are have a right to bear arms and protect themselves from threats but the 1978 War Powers Act, the Patriot Act, and the 2012 National Defense Authorization Act gives local, state, and federal governments the right to commandeer any supplies for the benefit of public good during times of disaster and they have a right to use “limited force” to secure necessary supplies.



Radius shelters have a hydraulic/manual hatch operation capable of lifting 10,000 pounds of debris off of the hatch. The hatch at ground level is made of Combat CompositeTM for various levels of bullet resistance from Class I to Class IV NIJ standards and designed to resist seven basic intruder assaults.


Radius shelters have a smooth sanitary closed pore inside surface that can be easily maintained in a sanitary condition with almost any cleaning solution. The C3 composite laminate has a Flame Spread of Class II under ASTM E 84 similar to epoxy coatings and shown above under the direct flame of a torch for 20 minutes.

inside_sur inside_sur2


lightingRadius shelters have LED lights with very low power consumption, very low heat generation, and over 50,000 hr average life. Lighting levels allow reading in all living areas inside the shelter.


elec systms Radius shelters have both 12 VDC and 120 VAC electrical systems. Battery banks store electrical energy and are maintained by a smart inverter/charger powered by the internal generator.  There are separate circuit breaker panels for AC and DC circuits and all wiring conforms to the NEC and/or ABYC codes.


plumbingRadius shelters have conventional high pressure water systems, water filters, showers, kitchen sinks, bathroom sinks, toilet with a sewage lift stations, and high pressure fiberglass leaching septic tanks conforming to conventional leach field standards. Water is usually supplied by a dedicated well but water tanks and other supply systems are available.


communicationRadius shelters come with a scanner to listen to what is going on outside and HAM radio to call for help if needed. The antennas are erected but not connected to the radios until after the disaster has passed. Various camouflaged surface mounted video observation systems are available.


appliancesRadius shelters have 120VAC wiring for appliances and consumer electronics. The larger shelters have 220VAC wiring and can power larger appliances like water heaters and full size dryers.


flowersfoodRadius shelters can be equipped with hydroponic and/or conventional growing systems. Larger shelters support aquaculture and farm animals to supplement the shelterist’s diet.


floorplansRadius shelters have standard floor plans but all can be customized. Floor plans typically include apartments, common areas, storage, food preparation, and exercise areas. Larger shelters have room for everything – offices, sick bay, animal treatment room, secure storage, restaurants, meeting rooms, crafts rooms, laboratories, swimming pool, half court basketball, putting green, vehicle and aircraft maintenance areas. All floor plans and facilities are designed in-house by our professional engineering and design departments.



Radius shelters are delivered by the a Radius truck and special trailer which does not require a Bill Of Lading so there is no paper trail to the installation site. All equipment delivered to site is by Radius truck.



Radius shelters have storage volumes for 6 months to 5 years of food and other supplies. Storage for fuel, grain, fish food, for the same amount of time is designed into the shelter.


Radius shelter protection for a completed and installed project including the product, delivery and installation ranges from $17,000 per shelterist to $80,000 per shelterist depending on the model, duration, interior trim level, site access, volume/shelterist, and life style required in the shelter. Customers are responsible for food, clothing, and personal items to make the shelter ready.



For large shelter systems, Radius works with the customer group to develop a Not For Profit Underground Shelter Co-Op Agreement where ownership or membership of the community shelter is defined. This agreement includes legal ownership and rights and all policies inside the shelter that shelterists agree to operate under before and after a disaster.


Radius Engineering International Inc. ® shelters represent the ultimate “STATE OF THE ART” technology providing NBCE protection for private, medical, military, and corporate installations in every state in the US and many countries. All the above key features have made Radius Engineering® International the largest underground shelter manufacturer in the world.