COMPOSITE STRUCTURE: Is flexible and durable unlike other shelters. There is no basement feeling, no tin can feeling, and not a retrofitted tank. These structures are designed as high pressure composite underground structures. They 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: Includes compound curved shapes with no catastrophic failure mode like round tanks. They have no flat walls and no tensile loads. They 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.
CONSTANT HULL PRESSURE RATING: 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 shelters are designed with an outward curve making the structure extremely strong and providing a much better atmosphere for claustrophobic shelterists. They range in rating from 15 psi (1.5 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.
RADIATION SHIELDING: 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, 2002 and 2011. The standard earth cover over all shelters is 8.5 ft of earth. The maximum radiation dose in any 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: The composite structures have no radar signature, minimal thermal signature, and with 8.5' of dirt above them are hard to find with ground penetrating radar. Camouflage and landscaping limit detection by digital imagery systems and direct observation.
ENTRANCEWAYS: Shelters are entered by conventional stairwells, spiral stairwells, ramps for the handicapped, tunnel ramps for vehicles, and various emergency escape tunnels. All connections from entranceways to the shelter and between shelters have a seismic joints allowing flexing during ground shock and normal earth movement.
SEISMIC JOINTS: All connections from entranceways to the shelter and between shelters have a seismic joints allowing flexing during ground shock and normal earth movement.
INTERNAL SHELTER PRESSURE: Shelters exposed to a blast, control the shelter internal pressure by Overpressure Choking so there are no moving parts. There is no use of obsolete technology using cumbersome blast valves that require maintenance and can get clogged by rodents and insects.
EMP PROTECTION: The shelter hulls are made of T2 Conductive Composite eliminating the conventional problems associated with corrosion. Shelters are also powered by internal generators to operate entirely "off the grid" so there is no risk of damage to internal equipment from EMP collected on grid power.
FOOD STORAGE BEAMS: 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.
AIR FILTRATION: 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 120 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 MCAS air filtration system supplies filtered breathing air for people and for the generator at a minimum of 15 cubic feet per minute per shelterist. The normal breathing rate for an adults human is 0.33 cfm (cubic feet per minute).
INTERNAL GENERATOR: Shelters have internal quiet slow speed generators providing power for off the local power grid. Fuel tanks are made of special structural fiberglass located inside the shelter for leak detection. Fungicides and circulating pumps maintain the 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 are operating in a composite structure and shielded from EMP by 8.5 feet of earth.
SECRECY: Secrecy can be an important part of the shelter location and construction. Shelters are generally used for temporary emergency structures with no foundation and no connection to local services therefore building permits for those things are not required (building permits are posted for public inspection). Earthcom structures have no concrete foundations or slab so there is no cure time installing a shelter. Shelters are installed by the manufacturer. No local contractors are used for the installation.
INSIDE SURFACE: Shelters have a smooth sanitary closed pore inside surface that can be easily maintained in a sanitary condition with almost any cleaning solution. The 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.
LIGHTING: 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.
ELECTRICAL SYSTEMS: Shelters have both 12 VDC and 120 VAC electrical systems (larger shelters have 220VAC). They can be equipped with battery banks or other electrical storage cells and are maintained by an smart inverter/charger powered by the generator. There are separate circuit breaker panels for AC and DC and all wiring conforms to the NEC and/or ABYC codes.
PLUMBING SYSTEM: Shelters have conventional high pressure water systems, water filters, showers, kitchen sinks, bathroom sinks, toilet with a sewage lift station, 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.
COMMUNICATIONS: Shelters can be equipped with a scanner to listen to what is going on outside and HAM radio to communicate with the outside world if needed. The antennas are erected from inside the shelter after the disaster has passed. Various camouflaged surface mounted video observation systems are available.