| Effect | Rank | Criteria |
| No | 1 | No effect |
| Very slight | 2 | Customer not annoyed |
| Slight | 3 | Customer slight annoyed |
| Minor | 4 | Customer experiences minor nuisance |
| Moderate | 5 | Customer experiences some dissatisfaction |
| Significant | 6 | Customer experiences discomfort |
| Major | 7 | Customer dissatisfied |
| Extreme | 8 | Customer very dissatisfied |
| Serious | 9 | Potential hazardous effect |
| Hazardous | 10 | Hazardous effect |