AbstractThe quantification of non‐structural seismic performance factors is a crucial step to improve the seismic performance of non‐structural elements (NSEs). Non‐structural seismic performance factors currently included in modern seismic design provisions are mainly based on engineering judgment and have not been calibrated to meet specific performance objectives. This makes the seismic performance of NSEs designed according to force‐based procedures uncertain at best. Previous studies have proposed a general framework for the quantification of non‐structural seismic performance factors. However, due to the necessity of considering the supporting structure dynamic properties in the estimation of the seismic demand, the required computational overhead can make the process unfeasible in some cases depending on the target supporting structure population and the pursued performance objectives. This paper proposes a procedure to estimate the seismic demand on NSEs for the quantification of non‐structural seismic performance factors that drastically reduces the required computational overhead. The proposed procedure makes use of synthetic floor accelerograms to describe in terms of seismic demand an entire population of supporting structures and ground motion sets. The proposed procedure is validated against a complete multiple‐stripe non‐linear time history analysis by deriving and comparing fragility curves. The results of the validation demonstrate that the proposed procedure is able to derive fragility curves that closely match the ones generated by using a multiple‐stripe analyses with remarkable savings in computational time and output storage size.