Safety system for use with a personal protective equipment for working in great heights comprising: wireless communication means configured to provide a communication with a rescue coordination center ; sensor means for providing sensor data comprising at least one acceleration sensor and at least one orientation sensor, wherein the sensor means are located in a separate sensor device attachable to a personal protective equipment; evaluation and notification means configured to determine a fall event and/or a loss of consciousness event based on the sensor data and to notify the rescue coordination center via the wireless communication means by sending an alert event message, a mobile computer device , wherein the sensor device and the mobile computer device comprise communication means, wherein the evaluation and notification means are configured to execute an evaluation algorithm based on the results of a machine-learning algorithm for determining a fall event and/or a loss of consciousness event in real time, wherein the wireless communication means, the evaluation and notification means are located in the mobile computer device , wherein the evaluation and notification means are configured to execute the evaluation algorithm even in case the mobile computer device is in a locked state, standby state or idle state, wherein the safety system further comprises a casing configured to receive the mobile computer device , wherein the casing is made of a material being electrically dissipative, wherein the material of the casing comprises an electrical resistivity of not more than 10 8 Ωm, wherein the material of the casing comprises at least one thermoplastic polyurethane and at least one inorganic filler, or at least one halogen-containing polymer and at least one inorganic filler, or at least one thermoplastic polyurethane, at least one halogen-containing polymer and at least one inorganic filler, wherein the casing is attached or attachable to a personal protective equipment. wireless communication means configured to provide a communication with a rescue coordination center ; sensor means for providing sensor data comprising at least one acceleration sensor and at least one orientation sensor, wherein the sensor means are located in a separate sensor device attachable to a personal protective equipment; evaluation and notification means configured to determine a fall event and/or a loss of consciousness event based on the sensor data and to notify the rescue coordination center via the wireless communication means by sending an alert event message, a mobile computer device , wherein the sensor device and the mobile computer device comprise communication means, wherein the evaluation and notification means are configured to execute an evaluation algorithm based on the results of a machine-learning algorithm for determining a fall event and/or a loss of consciousness event in real time, wherein the wireless communication means, the evaluation and notification means are located in the mobile computer device , wherein the evaluation and notification means are configured to execute the evaluation algorithm even in case the mobile computer device is in a locked state, standby state or idle state, wherein the safety system further comprises a casing configured to receive the mobile computer device , wherein the casing is made of a material being electrically dissipative, wherein the material of the casing comprises an electrical resistivity of not more than 10 8 Ωm, wherein the material of the casing comprises at least one thermoplastic polyurethane and at least one inorganic filler, or at least one halogen-containing polymer and at least one inorganic filler, or at least one thermoplastic polyurethane, at least one halogen-containing polymer and at least one inorganic filler, wherein the casing is attached or attachable to a personal protective equipment. <EOS>