This paper presents an approximate analytical solution to the problem of the lifetime of a toroidal shell operating under mechanochemical corrosion conditions under internal and external pressure, taking into account the possible inhibition of the corrosion process, using the Dolinsky — Pavlov corrosion kinetics model. The obtained estimates are applicable when the maximum stress is reached in the toroid’s intrados (in the absence of bending stresses), before the onset of corrosion localization. The solution allows evaluating the influence of the internal and external pressures, not just their difference. It is shown that the often-overlooked influence of the minimum of these pressures can become quite significant for decelerated corrosion, reducing the service life if the external pressure exceeds the internal one. The need for a comprehensive durability assessment, using various criteria and methods, is emphasized.