Buildings required by Section 9-12-1 to support adequate radio coverage which cannot support the required level of radio coverage required by Section 9-12-1 shall be equipped with approved bi-directional eight hundred (800) MHZ signal enhancement systems as needed. If amplification is used in the system, all required Federal Communications Commission authorizations must be obtained by the building owner prior to the use of the system. If any part of the installed system or systems contains an electrically powered component, the system shall be capable of operating on an independent battery and/or generator system for a continuous period of at least twelve (12) hours without external power input. The battery system shall automatically charge in the presence of an external power input.