The efficiency of the converter shall not be less than 90%,
                           but a higher efficiency of 95% is strongly recommended.
                        
                        
                        
                        
                           
                           
                           Note If, with the analyser in the most common range, the NOx converter
                              cannot give a reduction from 80% to 20% according to 7.2 above, then
                              the highest range which will give the reduction shall be used.