This document applies to pressurized gas-filled compartments of AC switchgear and controlgear with rated voltages above 1 kV and up to and including 52 kV for indoor or outdoor installations, where the gas or gas mixture is being used principally for its dielectric and/or arc-quenching properties and where the gases or gas mixtures in the compartment can be considered in conditions being chemically stable over its lifetime and non-corrosive to the material of the pressurized compartment in the conditions that prevail inside.