227.113—Noise operational controls.
               		
               	 	
               	 	
               	 	               	 	               	 	               	 	               	 	
               	 	
    
        
        (a) 
         Railroads may use noise operational controls at any sound level to reduce exposures to levels below those required by Table A-1 of appendix A of this part.
     
    
        
        (b) 
         Railroads are encouraged to use noise operational controls when employees are exposed to sound exceeding an 8-hour TWA of 90 dB(A).