The prohibitions contained in this chapter shall not apply to persons:
A. 
Who are engaged in the performance of any public or governmental function, such as the sounding of a church or school bell or a police, fire, ambulance, air raid or like disaster warning, alert or alarm, whether such alarm shall be for an actual emergency purpose or for practice or drilling purposes;
B. 
Who are engaged in any activity specifically permitted or required by any chapter, resolution, statute or governmental regulation; or
C. 
Employed by public utility companies engaged in emergency repair service; provided, however, that such noise does not exceed levels reasonably necessary to accomplish such work.