A process and device for the reliable monitoring of the current condition of the protective jacket formed of fireproof material, in particular of a rotary tubular kiln burner lance, during operation of the kiln system. A compressed air ring main and/or an annular metal wire loop forming part of an electrical circuit extending around the circumference of the protective jacket are embedded in the fireproof compound of the protective jacket in the area of the burner tip, in which in the event of burning through of the ring main or metal wire loop, a connected pressure sensor or current sensor generates a monitoring signal.