Is there a specification for the minimum number of safety luminaires that must be installed in an escape and rescue route or area to be supplied?

In order to be able to guarantee the so-called system integrity, at least 2 safety lights are required. This regulation ensures that in the event of a failure of a safety light, the rescue and escape route is not completely obscured or the marking becomes ineffective.

Source: DIN VDE V 0108-100-1 para. 5.3:2018