Abstract. Strict norms regarding the emission of harmful substances into the natural environment impose stringent requirements on engineers designing sealing units, especially when designing new mechanical seals. This especially concerns mechanical non-contacting seals with various surface layer modifications. Complex mathematical models that enable analyzing complex physical phenomena are developed to support the designing works. The presented paper includes specification of the impulse gas face seals mathematical model which takes into consideration the non-linear Reynolds equation. The mathematical model was solved based on the author’s computer program developed in the C++ language, thereby enabling a series of numerical tests and analyses on the phenomena taking place in the radial clearance during the seal’s operation. The paper also includes the final conclusions and a series of features specific for the subject impulse gas face seals.