Description: duration of operation between consecutive failures of a functional unit under given conditions; Name: otbf
Description: Operating time between consecutive failures ; Name: Operating time between failures
Description: norm/stipulation describing the explosion protection. The explosion protection type, the device category, the temperature class as well as the device / explosion group are taken from this norm. The type and number of the norm/stipulation with issue year and issue month must be given; Name: Reference norm of the explosion protection