I would look further as well to the very beginning of the standard:
1.3.2 The authority having jurisdiction shall determine compliance
with this standard and authorize equivalent deviations
from it in all applications.
1.5 Equivalency. Nothing in this standard is intended to prevent
the use of systems, methods, or devices of equivalent or
superior quality, strength, fire resistance, effectiveness, durability,
and safety over those prescribed by this standard.
Looking at this, you could establish a operating guideline between your department and CBO that all new installs going forward require both audible and visual.