Table 1.
Levels and values of assessment standards.
| Risk Grades | Range of Risk Value | Acceptability | |
|---|---|---|---|
| Grade I | Extremely low risk | <10−6 | Completely accept |
| Grade II | Low risk | (10−6, 10−5) | Not willing to care about the risk |
| Grade III | Low-medium risk | (10−5, 5 × 10−5) | Do not mind about the risk |
| Grade IV | Medium risk | (5 × 10−5, 10−4) | Care about the risk |
| Grade V | Medium-high risk | (10−4, 5 × 10−4) | Care about the risk and willing to invest |
| Grade VI | High risk | (5 × 10−4, 10−3) | Pay attention to the risk and take action to solve it |
| Grade VII | Extremely high risk | >10−3 | Reject the risk and must solve it |