... Now hear is the problem, my client in the past has had siezures... and from what I understand strobes have the tendecy to cause siezures.
There are a lot of things to consider here, but the population that experience this is 1 in 4000.
One thing you have to correct for in your case is when you have two, or more, visiual fire flash's that are viewable at the same time and are out of seqence to each other. This is due to voltage drop in the service and can be corrected with in-line resistors, based on the voltage drop.
Some manufactures recommends that the speaker and signal strobe always be used in combination so that the risks from any of the above limitations are minimized.
Here's two links
Epilepsy Foundation
A
search engine thats listed the same
A paragraph from the list:
Under the American Disability Act, and as specified in Underwriters Laboratories Standard UL 1971, the strobes must provide greater light intensity in order that the strobes can alone serve as a sufficient alarm indication to hearing impaired persons. Unfortunately, the strobes at the higher intensity levels have been reported to trigger epileptic seizures in some people.
Your client should know if they were tested for Photo Sensivity.