The flash prices of VADs are concerning 0.5 Hz and a couple of Hz. VADs could include a synchronisation operate to eliminate the potential for a flash frequency that may end in adverse results, for instance inducing epileptic fits, when products are in close proximity. Indicating Services Alignment with Evacuation https://www.firesense.co.uk/type/conventional-fire-system/conventional-sounders-vids-vads/