Seismic performance of Non-Structural (NS) components represents a key aspect in the design and safety assessment of both new and existing buildings. A significant number of these components can be classified as acceleration-sensitive and are often assumed dynamically uncoupled from the primary structural system. This assumption supports the widespread use of Floor Response Spectrum (FRS) approaches, which are well-established in the scientific literature and adopted by most building codes.This study examines the background and derivation process of the formulation currently adopted in the Italian Building Code (NTC 2018) for estimating the seismic acceleration demand on non-structural elements. An extensive parametric analysis is also carried out through numerical modeling of Reinforced Concrete (RC) frame structures, aimed at generating representative floor response spectra. The numerically obtained spectra are then critically compared with those proposed by current codes and major international standards.