| Gas Ratio | Range | Code |
| CH4/H2 (R1) | Not greater than 0.1 | 5 |
| Between 0.1 and 1.0 | 0 | |
| Between 1.0 and 3.0 | 1 | |
| Not less than 3.0 | 2 | |
| C2H6/CH4 (R4) | Less than 1.0 | 0 |
| Not less than 1.0 | 1 | |
| C2H4/C2H6 (R5) | Less than 1.0 | 0 |
| Between 1.0 and 3.0 | 1 | |
| Not less than 3.0 | 2 | |
| C2H2/C2H4 (R2) | Less than 0.5 | 0 |
| Between 0.5 and 3.0 | 1 | |
| Not less than 3.0 | 2 |