Application of passive defense in urban housing planning

Today، with advances in the technology of weapons and military equipment، urban areas are most at risk of invasion. Among the most important factors in enhancing human casualties in military attacks on urban areas، one can point to the unrealistic architecture of houses which does not conform to principles such as optimal site selection and layout of the structure of human settlements، proper distribution، principles of concealment، camouflage and deception، the high degree of vulnerability of buildings and interior architecture of buildings with regard to passive defense. Structural arrangement of spaces and their connection with surrounding areas has created great opportunities for saving lives And improves system performance and reduces its vulnerability. This study with a descriptive-qualitative approach، investigates the role of passive defense in urban housing planning and the conclusions are used to create safe city، strong city and deterrent city. Results show that determining the geometric design of house، pop location، availability and predictability of secure spaces are regarded as multi-functional space for each building in times of peace and war are among the optimal components of building architecture and vernacular architecture from the perspective of a passive defense. Crises، threats and disasters are classified into two main categories: natural، including earthquakes، floods، landslides، droughts and human category such as war، accidents and diseases which are more than 50 types. The main objective of this study is investigating crisis caused by war in residential areas. In the full-scale military conflicts، one of the ultimate goals of the parties involved is making an effort to bring the breadth and scope of the battlefield to civilian centers especially to urban centers، which is usually accompanied by heavy air strikes. This act is one of the most effective strategies in the fate of wars. Dragging wars to residential areas is usually accompanied by extensive damage and high human casualties and if there is no planning at macro measures in peacetime، during the war casualties would be double and it would bring terrible psychological burden for politicians and top military commanders. Among the main factors increasing the number of people killed and injured in the military attacks we can point to security attacks and natural and unexpected disasters occurring in urban areas and the high vulnerability of buildings which are resulted from the improper planning of housing، inadequate spatial layout and structured problems، construction engineering problems (unsafe structures and fortifications)، inappropriate architecture (not anticipating the shelter، open spaces، etc.)، non-standard communication networks and etc. Thus، regarding key principles underlying passive defense in buildings can be considered as bedrock for the development of sustainable security in urban areas. Another major cause of casualties in urban warfare is the population growth in urban areas due to excessive migration and unplanned growth of non-standard and unsafe human settlements in the margin of urban areas (e. g. Tehran metropolitan). So that in 1900، 29% of the world population lived in urban areas and in 1950، this rate increased to 49% and according to UN statistics; in 2010 this percentage was more than 75% (Vautravers، 2010، p. 438). Theoretical bases: The main objective of this study was to investigate and analyze structural and architectural factors affecting patterns of planning and design of housing in urban areas in order to deal with the effects of enemy invasion to residential areas and based on this، the hypothesis of the study has been developed which seems that the optimal pattern of planning of urban settlements and giving priority to housing planning based on defensive architecture and passive defense principles are among the major factors in reducing casualties and financial losses in residential areas during the crisis. The research method was descriptive - analytical. Data were gathered and analyzed through sources and documents available in libraries.

Urban housing Housing is one of the affect ive indicators in the mortality caused by military invasion to the cities. Since housing is known as the basic of urban fabric. The housing issue is broad and complex and has various dimensions. Housing has a physical location and is regarded as a shelter، basic and primary need of individuals. In this shelter، some of the family or individual''s primary needs such as food، rest، and protection against environmental conditions are met (Pourmohammadi، 2009، 3). Housing planning is part of the urban planning in which residential units are considered as part of the deformed and adopted spaces which will be considered with regard to their subjects in the housing planning framework. Based on this، housing planning deals with allocating habitable spaces to needs of residential housing and paying attention to the limitation of resources and the use of special techniques، theories with social، cultural، political and economic frameworks. Passive defense principles in the design and construction of urban human settlements Defensive architecture of the building is presented in order to get ready for more attacks against military and other natural disasters. Passive defense considerations in housing are crystallized in three categories of architecture، structural strength and installations. In architecture، attending principles such as optimal site selection and layout of buildings، the proper dispersion، observing such principles as camouflage، concealment and deception principles and high-grade restoration of interior architecture of buildings is important (Faraji Mollaei and Azimi، 2011، 998). The structural arrangement and connection with surrounding areas has provided great resources to save lives and has improved the system performance and reduced its vulnerability. Determining the geometric design، pop location، availability and predicting secure spaces as multiple performance spaces for each building in peacetime and war are the responsibility of architects. Architects should design the space to suit the needs of the user so that in addition to the defensive performance in the time of war، it has appropriate use in time of peace (21st issue of the National Building Regulations، 2009، 3-4). The structural aspect of buildings deals with how to design the building to resist the explosive loads. This work is the responsibility of Structural Engineers. In order to have the right structural system and choosing the appropriate section of the building for secure space، architectural plans must be coordinated with the structural issue. In the facility sector، it is to prevent the damage caused by the blast effects، such as gas leaks، flooding، electrical hazards، fire and installing alarm system. Limited utilization capacity or variability of building facility systems consistent with the desired performance is considered by facilities engineers.

Urban housing planning must be designed and implemented under this title. In addition to attending the social، economic and security issues، it should seek to achieve the goal of increasing the nation''s capacity to deal with threats and potential harms and to promote empowerment and national tolerance for dealing with emergency situations. From the discussed issue، we can conclude that it is possible to decrease the severity and extent of damage caused by enemy attacks during crises cassette through applying appropriate architecture measures with a defensive approach، considering the 16 principles of passive defense consistent with the physical and special properties of cities and especially in urban residential areas، while creating beautiful spaces without compromising space and their functionality and without spending too much cost. This work involves the national resolute determination of relevant organizations which is possible with the cooperation and synergy of organizations. Suggestions: In order to reach housing programs with an appropriate level of safety based on passive defense principles the following suggestions are offered: Comprehensive housing plan for the development of quality of buildings along its quantitative development. Considering the safety of the buildings. Preparation of passive defense guidelines based on safe housing planning. Compilation of architectural document requirements in the design of buildings with passive defense approach. Planning for reducing physical instability of residential buildings in the historic fabric and marginal areas. Paying special attention to textures and old residential areas in central cities، and granting support from government facilities for strengthening، upgrading and refurbishment of old buildings.