Single-storey precast RC buildings not originally designed to withstand seismic actions showed their vulnerability during the Emilia Earthquake events (2012). The legislation that followed this catastrophic event has highlighted the need to assess and raise their seismic performance, even if interventions are limited to the connections between structural elements. The need to evaluate the conditions of existing buildings and to compare the effectiveness of risk mitigation interventions has highlighted the importance to have rapid assessment tools to check seismic vulnerability. The procedure proposed below begins by considering a simplified energy approach and allows the quantification of the seismic vulnerability of a precast RC building using few significant parameters. 

The proposal, for this specific type of building, works by comparing the characteristics of a new structure, assumed to be like the one to be assessed and designed for the seismic action of the specific site, to the existing structure to be assessed. The seismic vulnerability is subsequently defined in terms of the percentage of deviation of the real structure from the ideal one. The quantification of the percentage of deviation, based on macro-parameters, is estimated in terms of the capacity to absorb and resist the seismic input, described through energy. The SISMO-Fast method is based on the evidence of damage mechanisms observed during the site survey performed after the 2012 Emilia earthquake and other recent seismic events. The procedure has been used, for rapid seismic vulnerability assessment of some industrial precast RC buildings in different seismic areas, providing always reliable results.