831.1109—Evidence.
        
        (a) 
         Rules of evidence are not strictly applied, but the presiding officer shall exclude irrelevant or unduly repetitious evidence.
    
    
        
        (b) 
         Each exhibit of a documentary character shall be submitted to the presiding officer, duly marked, and made a part of the record. An exhibit does not become evidence unless received in evidence by the presiding officer.