Official highway route number signs, street name signs, directional, or other official federal, state, county, or Township signs. This shall include signage located at Township municipal buildings, police departments, public educational institutions, and buildings housing Township designated EMS and Fire Department equipment and personnel. Electronic changeable display signs shall specifically be allowed upon such properties subject to approval by the Board of Supervisors in the best interests of public health, welfare, and safety. No light source for any changeable display sign shall produce a nuisance or safety hazard. Changes in the signage display shall include the entire display such that different portions of the display do not change at different times. Any sign with flashing, moving, sound producing, or animated parts is prohibited upon such properties. Electronic signage must receive the proper required electrical permits as part of installation.