Because of crises arising from natural disasters and wars which have been more intricate and because of employing science and technology in modern wars a different type of non- operational defense is required. Checking out the latest wars shows that damaging public buildings -directly and indirectly- because of attacks, which are mostly propagated as military mistakes or other excuses, causes increasing human casualties as a result of the  buildings destruction due to hit  the bomb and waves of explosion arising these bombardment; so it is necessary, in the event of a crisis, unexpected incident or any attack the hospitals that are high- importance spaces, to preserve their efficiency to the maximum possible and to the maximum time and get the least amount of damages and cause the minimum human casualties. Undoubtedly, sciences related to architecture and urbanism play an important role in reducing casualties when the crises arise. In the same way, the architectural form of medical buildings has a significant role in the sustainability of the therapeutic structures during the war and the reduction of the damage caused by the explosion and earthquake during the crisis; so, in order to prevent the occurrence of these problems and to minimize the damages and casualties when the crises happen, the safety and security issue should be considered from the great issues to the technical details of the architecture. The main issue in this study is the lack of codified and expanded indexes to assess the sustainability of types of form combinations and the advantages and disadvantages of each type from viewpoint of passive defense.
In the present research, which is an applied kind of researches, library study method has been used for data and information gathering, while reviewing researches which have done formerly in the field of passive defense, describes passive defense from the viewpoint of the experts and evaluates the optimal forms and volumetric compounds in the terms of sustainability against the explosion wave. This research is looking for suitable forms as one of the architectural approaches to deal with this kind of threat, which ultimately leads to requirements and considerations for architectural design of the hospitals from the viewpoint of passive defense.