In this paper, the key technical issues associated with post-earthquake emergency inspections operations of buildings are presented and recommendations are made based on extensive local (Greek) experience from past earthquakes. Safety and usability criteria are established and correlations of such criteria with various damage states are given, along with detailed rules of damage assessment for reinforced concrete and masonry buildings. The damage states of various structural as well as non-structural elements are quantified and their descriptions are supplemented with appropriate photographs of damage in past earthquakes. Rules are then provided for assessing the overall safety of a building based on the severity and extent of damage of its elements. Organisational and logistical aspects of such operations have been presented and discussed in a companion paper (Part 2).