Combustion Efficiency Chart for Natural Gas  

 

 Power Burners                                                                 Recommended Ranges  

Excess

Air  

%

O2

%

CO2

Net Stack Temperature — Degrees Fahrenheit

300

320 340 360 380 400 420 440 460 480 500
9.5 2.0 10.7 83.1 82.6 82.2 81.7 81.2 80.8    80.3 79.8 79.4 78.9 78.4
12.1 2.5 10.4 83.0 82.5 82.0 81.5 81.1 80.6 80.1 79.6 79.1 78.7 78.2 
15.0 3.0 10.1 82.8 82.3 81.8 81.4 80.9 80.4 79.9 79.4 78.9 78.4 77.9
21.1   4.0 9.6   82.5  82.0 81.5 81.0 80.5 79.9 79.4 78.9 78.4 77.9 77.4
24.5   4.5 9.3   82.3  81.1 81.3 80.8 80.2 79.7 79.2 78.7 78.1 77.6 77.1
28.1   5.0 9.0   82.1 81.6 81.1 80.5 80.0 79.5 78.9 78.4 77.8 77.3 76.7
31.9 5.5  8.7   81.9 81.4 80.8 80.3  79.7 79.2 78.6 78.1 77.5 77.0 76.4
35.9   6.0 8.4   81.7 81.1 80.6 80.0 79.5 78.9 78.3 77.8 77.2 76.6 76.0
40.3   6.5  8.2 81.5 80.9 80.3 79.7 79.2 78.6 78.0 77.4 76.8  76.2 75.6
44.9  7.0 7.9 81.2 80.6 80.0 79.4 78.8 78.2 77.6 77.0 76.4 75.8 75.2

  

Atmospheric Burners

Excess

Air

%

O2

%

CO2

Net Stack Temperature — Degrees Fahrenheit

 300 320 340 360 380 400 420 440 460 480 500
28.1 5.0 9.0 82.1 81.6 81.1 80.5 80.0 79.5 78.9 78.4 77.8 77.3 76.7
31.9 5.5  8.7  81.9 81.4 80.8 80.3  79.7 79.2 78.6 78.1 77.5 77.0 76.4
35.9 6.0 8.4 81.7 81.1 80.6 80.0 79.5 78.9 78.3 77.8  77.2 76.6 76.0
40.3 6.5 8.2 81.5 80.9 80.3 79.7 79.2 78.6 78.0 77.4 76.8 76.2 75.6
44.9 7.0 7.9 81.2 80.6 80.0 79.4 78.8 78.2 77.6 77.0 76.4 75.8 75.2
49.9 7.5 7.6 80.9 80.3 79.7 79.1 78.5 77.9 77.3 76.7 76.0 75.4 74.8
55.3 8.0 7.3 80.7 80.0 79.4 78.8 78.1 77.5 76.9 76.2 75.6 74.9 74.3
61.1 8.5 7.0 80.4 79.7 79.1 78.4 77.8 77.1 76.4 75.8 75.1 74.4 73.8
67.3 9.0 6.7 80.0 79.3 78.7 78.0 77.3 76.6 76.0 75.3 74.6 73.9 73.2

Courtesy of The Boiler Institute