This chapter examines the methodological framework for designing facilities for the protection of people and underground facilities from internal explosions. The basic requirements to be fulfilled by protective systems, considering the characteristics of shock wave propagation in the limited space of underground structures, are established. A structure for an automatic protective system is proposed with a module for identification of the explosion and a blast energy absorber at its centre. Research carried out by the CIPPS (University of Florida) and the Tsulukidze Mining Institute (Georgia) was aimed at increasing the reliability of blast identification in tunnels and developing design parameters for a shock absorber.