The DIBt building rules list requires a verification of applicability for fire protection closures (a German approval from the building inspectorate or a European technical approval). These approvals stipulate a locking device when the systems are to be kept open in operation. The locking device must be suitable. It applicability must be verified by means of an approval from the building inspectorate.
Standards & Code References
Z-6.5-1990 for conveyor system closure
Fire alarm analysis
Pushbutton • Potential-free contact of central fire alarm system • Via fire alarm loop or smoke switch