This leaflet discusses the multitude of aspects to be considered in design of modern shelters: SRWHQWLDOWKUHDWDQG

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1 )RUHZRUG From the dawn of history, man has made great efforts to defend himself against unfavorable effects of nature as well as attacks by other man. Just a few years ago, a military base, city or public utility center well behind the front line was considered immune for threat and destruction. Today, there is no front line and the lethality of the battlefield threatens every civilian city or military installation. In modern warfare, sophisticated satellite surveillance, highly organized intelligence network and smart weapon delivery systems make all targets vulnerable. To meet this threat, the design engineer has a great challenge at hand to develop new methods to protect human lives and vital facilities. One of the most effective ways to respond to the threat of modern warfare is to provide hardened shelters for people and vital functions to be protected. While it has been realized that it will not be possible to construct a shelter that would be totally immune to destruction, it has been clearly demonstrated that it would still take great efforts from the aggressor to destroy a well fortified target. When the assailant sees a strong fortification, it is highly probable that he refrains from attacking at all considering his own losses and expense. In this way, a shelter is well comparable to an insurance policy thus being a well justified investment. This leaflet discusses the multitude of aspects to be considered in design of modern shelters: SRWHQWLDOWKUHDWDQG WKHHIIHFWVRIZHDSRQVVKHOWHUKDUGHQLQJWHFKQRORJ\DQGWKHVLJQLILFDQFHRIOLIHVXVWDLQLQJV\VWHPVWKHQHHGIRU UHDOWLPHGHWHFWLRQRIWR[LFDJHQWVEDVLFUHTXLUHPHQWVIRUFRPPXQLFDWLRQVHFXULW\V\VWHPVDVZHOODVWKRVHIRU VKHOWHURSHUDELOLW\DQGPDQDJHPHQW :HDSRQHIIHFWVDQGWKUHDWVFHQDULRV Despite the great efforts and numerous arms limitation treaties, the weapon arsenal in the world is still more than sufficient to destroy all life on the earth. The threat posed by nuclear weapons and the scale of damage resulting from their use has been recognized ever since they were first used to end the Second World War. The devastating power and effectiveness of modern conventional weapons was clearly demonstrated during the conflicts fought in the Middle East and even in Europe throughout the 90 s. Today, when a world-wide crisis is not considered a potential danger protective measures should be focused on threat scenarios of local conflicts which may break out almost everywhere. These will be fought with ever more effective conventional weapons with all time present danger of chemical or biological warfare. In any case, even with the most accurate guided weapons intended for surgical destruction of military targets only, without proper shelters the civilians suffer great casualties and are the true losers in modern warfare. Another likely scenario is a detonation of nuclear device or release of toxic agents as result of mere accident or terrorist actions. These cases may have long-term effects over large areas. Sheltering is by far the most effective way of protection also against these unwanted incidents. Photo: LEHTIKUVA

2 Conventional weapons Gun bullets, shells, rockets, mines, missiles and other explosive devices are conventional weapons potentially used against shelters and other hardened protective structures. They affect the target in many different ways depending on the point of impact and explosion. The main effects of conventional weapons are penetration, highpeaked blast overpressure, shock load and demolition. Nuclear weapons The effects of nuclear weapons are long duration positive and negative blast pressure, ground shock loads, intense thermal radiation, nuclear radiation and fallout and electromagnetic pulse. Photo: LEHTIKUVA When the blast arrives, the pressure rises rapidly from normal atmospheric pressure to its maximum value and then decays back to normal within fractions of a second. This positive phase is immediately followed by a negative suction phase when the pressure drops below normal for a short time. These sudden changes in loading causing dynamic response of the structure require special attention of the structural designer. Shock resistance is required to provide protection against rapid movements induced by the overwhelming blast energy. Thermal radiation directly from the explosion has very short duration and will only burn the exterior surfaces of the shelter structures. The explosion may, however, start long lasting fires around the shelter removing oxygen from the air and providing excessive heat load. Photo: LUONNONKUVA-ARKISTO Nuclear radiation is divided into three categories: initial nuclear radiation emitted within about one minute from the explosion, residual radiation emitted later and fallout which is radioactive material rising up with the plume and coming down sooner (local fallout) or later (delayed global fallout). Electromagnetic pulse (EMP) is a sharp pulse of intense radio frequency electromagnetic radiation produced when a nuclear explosion occurs in an asymmetrical environment. The intense electric and magnetic fields can damage unprotected electrical equipment over a large area but does not harm living organisms. Chemical and biological weapons Chemical and biological weapons are a wide group of irritating, poisoning and pathogenic agents which are sprayed or delivered to the target by many various means. The most potential toxic agents possibly used by terrorist groups or by rogue governments are mustard gas, nerve agents such as sarin, soman or VX as well as Botulism Toxin, Anthrax and Variola spores, but practically all existing diseases and those engineered in laboratories could be used as weapons if handled correctly. Photo: SA-KUVA

3 (OHPHQWVRIVKHOWHUGHVLJQ A modern shelter is to be designed like an industrial process the objective being to keep people alive. During crises massive shelter structures provided with special protective equipment form a protective boundary between the outside and the protected space providing the desired level of protection for people, property, equipment and life sustaining systems against all harmful effects. The shelter design is very much like balancing scales between protection level and construction cost. The more the owner is ready to invest the higher level of protection can be reached. It is of vital importance in shelter design to agree upon the weapon effects with the client and to derive the pertinent design loads thereof. Only then will the desired protection level be reached. Hardening technology The inside environment of the shelter must be isolated from the outside world by means of necessary protective barriers or boundaries. A modern shelter has multiple requirements for protection boundaries such as impact and penetration protection, blast resistance gas tightness and EMP-protection. These boundaries are usually physically constituted by reinforced concrete and comprise several special protective equipment such as blast resistant and gas tight doors to seal the passageways and blast valves to protect the shelter ventilation system. Blast hardening One of the most important elements of hardening technology is the design against blast effects as this will to great extent define the thickness of the shelter walls and thus dictate the overall cost of the shelter, and it will also set the requirements for special blast resistant equipment. A good way to illustrate the challenge given to a structural engineer is to apply a destruction curve analysis for evaluation of the structural resistance of the shelter as well as the resistance of blast proof doors, wall sleeves and ventilation system blast valves. A destruction curve can be computed for any elasto-plastic structural member subject to dynamic loading by solving the system equation of motion with a number of load-time relations ranging from short duration impulsive load to quasi-static load. For complex components such as blast valves, the destruction curve can be obtained by testing with various peak pressure/duration load combinations. Particularly for a blast valve, the destruction curve can also be viewed as a curve featuring the range of the valve applications: when the applied load points are below the curve, the valve can safely be used for the application, and when the load points are on or above the curve, a heavier valve must be chosen. The graph below features the destruction curve for a typical Temet blast valve. The corresponding range of applications curves for most of Temet blast valves are incorporated in the pertinent product catalog PD[YHULILHGVKRUWGXUDWLRQSUHVVXUH 5000 SHDNSUHVVXUHN3D UDQJHRIVDIHORDG UDQJHRIXQVDIHORDG 2000 PD[VDIHORQJGXUDWLRQSUHVVXUH GXUDWLRQPV

4 Gas tight boundary When the shelter is to be hardened against the entry of toxic agents, proper arrangements for gas tight closing of all access ways and ventilation openings must be provided for to make possible maintaining of an artificial atmosphere in the shelter. In practice, this implies installation of gas tight doors and hatches in access ways and gas tight valves in ventilation openings penetrating the gas tight boundary of the shelter. Watertight boundary When the shelter is located under the ground water table, the structure and all its joints are to be designed against the penetration of ground water. EMP-boundary The shelter space containing sensitive electronic equipment shall be shielded with metal sheeting or steel mesh. All ventilation openings must be provided with EMP-grilles and other penetrations with EMP-filters. Shock isolation Explosion occurring at contact or close to the structure causes shock loads. To protect the equipment not designed for severe shock, they must be mounted on special shock isolators that prevent the propagation of these load effects. Temporary life supporting systems Modern weapons are capable of making the environment hostile and impossible to live in. The aggressor can achieve this in several ways using the weapons described herein. Therefore, it is necessary to create an artificial atmosphere inside the shelter to provide the sheltered people with minimum supplies for survival. Ventilation During a close-up period the air inside the shelter is circulated, filtered, conditioned and blown back into the shelter. If necessary, oxygen will be added and carbon dioxide removed with special equipment. The shelter is kept at slight overpressure. During a filtration period a minimum amount of outside air is taken into the shelter through the fresh air channel and blast valves. This outside air is filtered in special NBC (Nuclear Biological, Chemical) filters, mixed with the circulated air and blown into the shelter. The NBC filtration system also maintains a positive pressure inside the shelter to ensure that no contaminants will enter the toxic free areas. During a by-pass period as well as during normal time use the outside air is taken directly into the shelter. The exhaust air from the shelter is evacuated through toilet areas and entrances.

5 Air conditioning Unless the shelter structures and surroundings can absorb the excessive heat produced in the shelter, an air conditioning system has to be provided to cool the air and to keep the temperature within tolerable limits. The condensers located outside the gas tight boundary are usually protected against blast and other direct effects of conventional weapons in order to guarantee full functionality in all circumstances. The arrangements for heating are not nearly as critical as those for cooling. Power supply Reliable power supply is essential for life supporting systems of the shelter. The shelters are connected to the local power distribution network. For power failure, all the life supporting services shall be secured by a diesel driven stand-by generating set. The number of stand-by units depends on the significance of the shelter. Harsh shelter conditions require reliable and sturdy lighting fittings and wiring, protected against high humidity and vibration. Besides the back-up energy, emergency lighting is also provided by batteries for important rooms and corridors. Photo: LEHTIKUVA Supplies and disposal Water tanks are required to hold adequate drinking and personal hygiene water for all occupants in the shelter. A food storage shall contain dry and canned food. Beds, a radio, rescue equipment and basic medical supplies shall be available. An adequate storage of oil shall also be provided for the emergency diesel generator set. The sewage and possible leakage water inside the shelter shall be collected into a sewage tank by gravity and pumped out when possible. Dry toilets shall be used instead of water toilets during the sheltering periods.

6 Chemical agent detection in fixed shelter installations Lack of real time monitoring of the outside air compromises the NBC protection of the shelter Hardening the shelter against the entry of toxic gases and providing the ventilation system with the most effective filtration system will not as such guarantee the safety of the occupants in the shelter. The lack of real time monitoring of the purity of the shelter simply makes it impossible to use the shelter ventilation systems efficiently. Chemical agent detection - vital tool for operative management of the shelter A modern NBC-hardened shelter shall be equipped with an electronic chemical agent detection system. The purpose of such a system is to give right information to the shelter management and thereby facilitate a correct sequential use of the three sheltering modes, normal time or by-pass mode, close-up mode and filtration mode. In order to be effective in fixed shelter use, a chemical agent detection system has several special requirements not necessarily emphasized in a detector in portable or field network use. The special requirements set for a fixed detector system are featured in the following: - the system must be designed for continuous monitoring of the intake air with minimum maintenance required during the service life time - the system must be capable of differentiating between nerve gases and other toxic agents. This is very important due to the much higher toxicity of nerve agents compared with other chemical warfare agents - the system must have a very short response time. Fast response is vital so as to limit the total amount of toxic agents entering the shelter prior to taking protective measures - the system must be capable of detecting when the gas concentration has decreased below harmful level to make possible return to normal time ventilation and flushing of eventual residuals from the shelter air - the system must be capable of being integrated with the NBC filtration unit of the shelter and supplying relevant control information for fully automatic operation of the shelter ventilation system It may also be important to receive more specific qualitative and quantitative data on the toxic agent possible entering the shelter. Therefore, a mere fixed chemical agent detector system may not be sufficient for proper management of the shelter. In that case, the shelter must be provided with a multicomponent gas analyzer tuned for detection and analysis of chemical warfare agents. More information on FT-IR gas analyzer is available from Temet.

7 Communication and security systems External communications Shelters shall be provided with a telephone system for external communications. The telephone system includes extensions, public exchange trunk lines, private trunk lines and data communications. Incoming calls from the public network shall be possible to route directly to the extensions or through the telephone operator. A radiotelephone system is a wireless link system. Transmission is sent from the base station and received by a radio link. Incoming calls can be connected to separate radiotelephone sets or to normal telephone sets through the telephone operator. All communication can be wired through one common multichannel recording system for documentation. Internal communications For internal communications the shelter can be provided with a public address system. It serves for voice announcement and radio programs. Loudspeakers can be divided into several distribution groups and direct information only to those areas considered necessary. Audiovisual systems are intended for aid in decision making and for educational purposes. These systems use computer or video system as signal source and display via data or video projectors or monitors. Electronic maps may also be used. Security systems Alarm and warning systems are functioning to prevent and warn from any hazardous situation. A fire alarm system detects and warns of fire at all times. The quality of the outside air can be monitored by means of a multicomponent gas analyzer. A plant monitoring system supervises the status of the shelter doors and ventilation valves continuously. For peace time use the outside doors can be equipped with remote controlled locks, card readers and intercom door sets supported by CCTV cameras. Persons accessing can be identified from a TV-monitor located in the shelter control room. Photo: LEHTIKUVA

8 7HPHW2\ Asentajankatu 3 FIN Helsinki, Finland tel fax firstname.lastname@temet.fi internet: 7HPHWSURGXFWUDQJH Blast resistant & gastight doors Custom designed protective doors Blast valves & gastight valves NBC Filters and filtration systems Chemical warfare agent detection systems Shock protection systems Ventilation sound attenuators TECHNOLOGY FOR SHELTERS AND PROTECTIVE STRUCTURES FROM FINLAND Operability and management Shelter operations A modern hardened shelter is a very complicated technical system designed to help people to survive even in most difficult situations. The higher the shelter protection class, the more sophisticated the life sustaining system, and the more staff is needed for its operation. In case of emergency the life of the sheltered people depends on the equipment. For this reason, it is highly important that the management and staff of the shelter are well trained for their jobs and capable of operating the system even in exceptional circumstances. Peace time use The cost of shelter buildings having medium or high protection class is considerable, but with a suitable peace time use the operation cost of the shelter can be minimized and even part of the investment can be recouped. This should, however, not disturb the use of the building as a shelter, and the transition from peace time use into the emergency use should be performed rapidly. The shelter management should be responsible for the shelter operation also during peace time and should take care of the storage and supplies as well as necessary test runs of the equipment and practical drills for the staff. Sheltering periods Shelters designed against NBC threats usually have different functional modes that must be managed during the sheltering. The sheltering is usually started with a close-up period. As long as the toxic agent content in the air is too high, there is carbon monoxide in the air or a sever fire outside, the sheltering is continued in a close-up mode. As soon as it is possible to purify the air with filters, a filtration period will be started. When the danger has passed, the filtration period will be followed by by-pass mode with increased ventilation rate for flushing the shelter with fresh air. Civil Defence management The main duties of Civil Defence personnel are training, evacuation, early warning, sheltering and relief action. On the level of sheltering during emergency situations, this means collecting and distributing information on the current situation and threats through the communication systems. The shelter management should be trained to select the relevant data and operate the shelter accordingly. 6KHOWHUVDVSDUWRIWKHGHIHQFHSROLF\ For anyone faced with the threats present in today s world but not having complete confidence in the abilities and good will of the governments to disarm and to prevent the possibilities of aggressive or accidental attacks or to make industrial plants and transportation facilities safe, the only remaining option is to make plans for evacuation, implement an efficient early warning system and construct shelters designed against the expected threat. Building shelters shall be considered as an investment in security. The more money the defender invests in his shelter, the more money the aggressor must spend in order to reach his objective. Thus the shelters work like an insurance policy with people paying for the premiums and naturally hoping the need for sheltering will never materialize. Should the worst happen, however, the shelters will pay back. Photo: LUONNONKUVA-ARKISTO