Supplied Air Respiratory Protection means that breathing air delivered to a fresh air welding helmet is created by a compressor. Supplied air sources must meet mandatory local breathable air quality regulations.Welder's respirators connected with a breathable air supply from a compressor meeting EN 12021 are defined under EN 14594. The Kemppi welder's respirators must only be used in areas where the oxygen content exceeds 17% and must not be used as a self-contained breathing apparatus, or for escape purposes.