Understanding the risk presented to buildings by bioterrorism has been a topic of research interest in recent years. Risk assessment methodologies and guidelines for the protection of buildings have been developed by a number of researchers, but it remains difficult to quantify the vulnerability and resilience of a building. It is an important issue from both biosecurity investment and operation point of view because different measures have different cost and operation implications. This paper reviews existing risk assessment methodologies, introduces a novel framework for classifying protection measures, and determines the inter-relation of the framework components and building vulnerability and resilience using a fault tree analysis within a biosecurity network system. Future work will develop weighting values for the different protection measures within the framework, allowing for the calculation of bioterrorism resilience of existing buildings, and to provide a decision making guide for building architects, builders, and managers for new and retrofitted buildings. The physical decay of BWA in the indoor environment refers to the loss attributable to physical factors such as unrestricted diffusion, surface impaction, and fall-out. Unrestricted diffusion allows the movement of aerosolized particles out of the zone where the pathogen was released into other areas within the building, or the external environment. This dilutes the concentration of the particle in the indoor air, but can also lead to the spread of the pathogen to areas of the building not directly targeted. Surface impaction refers to the attachment of contaminants to surfaces, while fall out refers to the deposition of the contaminant particles on surfaces due to gravity. Physical decay does not necessarily eliminate the threat, but may remove it from the indoor air, although the risk of re-suspension can remain.The biological decay of BWA within the built environment depends on the type of pathogen, and the surrounding environmental conditions. Potential pathogens used in bioterrorism can exhibit a range of survival times in the environment. The persistence of pathogens is dependent on environmental conditions, including the temperature and relative humidity of the indoor environment and solar radiation levels [3]. Fungi and some bacterial species, for example Anthrax, can form spores, allowing them to survive desiccation and remain viable for years. The nature of the BWA and the means of delivery of the contaminant to the building will dictate the threat and the consequences of an attack.
Threat analysis for buildingsA successful bioattack on a building will be a product of a number of factors, including the terrorists' resources, capabilities, and decisions, actions by other individuals and/or groups, and the buildings resilience. Assessing terrorism risk in specific buildings is often considered to be a combination of the threat of an attack, the vulnerability to the attack, and the expected consequences of theattack.
Risk threat vuln...