Table 3.
A sample of the SPAR-H worksheet for dependency determination in “flammable gas testing” task
| Condition number | Crew (some or different) | Time (close in time or not close in time) | Location (some or different) | Cause (additional or not additional) | Dependency | HEP calculation formula |
|---|---|---|---|---|---|---|
| 1 | s | c | s | na | Complete | The probability of failure is 1 |
| 2 | a | Complete | ||||
| 3 | d | na | High | (1 + PW/OD)/2 | ||
| 4 | a | High | ||||
| 5 | nc | s | na | High | ||
| 6 | a | Moderate | (1 + 6 × PW/OD)/7 | |||
| 7 | d | na | Moderate | |||
| 8 | a | Low | (1 + 19 × PW/OD)/20 | |||
| 9 | d | c | s | na | Moderate | (1 + 6 × PW/OD)/7 |
| 10 | a | Moderate | ||||
| 11 | d | na | Moderate | |||
| 12 | a | Moderate | ||||
| 13 | nc | s | na | Low | (1 + 19 × PW/OD)/20 | |
| 14 | a | Low | ||||
| 15 | d | na | Low | |||
| 16 | A | Low | ||||
| 17 | Zero | The probability of failure is PW/OD |
a, additional; c, close in time; d, different; HEP, human error probability; na, not additional; nc, not close in time; PW/OD, probability without dependency; s, same; SPAR-H, standardized plant analysis risk-human.
Note: Gray color shows the selected dependency level and its corresponding formula for HEP calculation.