Two types of fire alarm beacon are acceptable as a visual alarm device: Xenon & LED. EN54-23 specifies that whatever the position of the individual in relation to the VAD, the occupant must see the flash off surfaces.
For complete coverage of the industrial example shown the following will be required:
12 Traditional Xenon Beacons or 1 LED beacon
to achieve the required 04 lux in the area of coverage.
It's not only in coverage where LED comes out on top. LED outlasts Xenon with up to 50,000 (70 months) continuously flashing compared to 14,000 hours (2 months) and it requires a much smaller enclosure due to its lower heat output.