Work time arrangements and work systems that might have a negative impact on an individual's ability to adjust to shift work include but are not limited to:
| (a) | a shift roster with an irregular or unpredictable pattern. |
| (b) | more than four consecutive 12-hour night shifts. |
| (c) | more than five consecutive 8-hour night shifts. |
| (d) | work schedules/rosters that do not allow opportunity for continuous sleep of seven to eight hours in each 24-hour period. |
| (e) | excessive regular overtime and on-call work. |
| (f) | early morning shift start times (before 6:00). |
| (g) | backward rotating rosters (day to night to afternoon). |
| (h) | shifts lacking appropriate shift breaks. |
| (i) | less than 36 hours off after a period of night shift work. |
| (j) | 12-hour shifts that involve critical monitoring tasks, heavy physical work, potential exposure to harmful agents/substances. |
To assess the fatigue risks caused by shift systems and work time arrangements at a mine site, the relevant risk factors should be examined in detail in detail (Table 1.1).
Table 1.1:
Risk assessment of shift systems and work time arrangements
Risk factor
|
Consideration
|
Shift schedule design factors
|
Night shifts, including the number of consecutive night shifts
|
| • | Are too many consecutive night shifts worked? |
| • | Is more than eight hours' work required over-night shift? |
| • | Are tasks requiring sustained physical or mental effort undertaken on night shift? |
| • | Are complex physical or mental tasks undertaken on night shift? |
| • | Do night shift workers have difficulty getting undisturbed sleep during the day? |
|
Long hours of work in a single shift. This includes travel time, especially to remote sites
|
| • | Does one shift involve more than 12 hours in a day (including call-outs)? |
|
Long hours of work across a shift cycle
|
| • | Do hours of active work (total time spent at work including overtime) exceed 50 hours in any seven days? |
|
Long hours because of on-call duties
|
| • | Are there irregular and unplanned schedules as a result of call-outs? |
| • | Is the working day or working week extended beyond 12 hours in a single day or hours in any seven days as a result of call-outs? |
|
Short breaks between work shifts
|
| • | Is there enough time between work shifts to allow for adequate sleep: |
| - | Enough time in a break for five hours' uninterrupted sleep in 24 hours (only for one night)? |
| - | Enough time in breaks for 12 hours of sleep in 48 hours (i.e. in two days)? |
| - | Enough time in breaks for 50 hours' sleep in 7 days? |
| - | Is the break between shifts less than 10 hours? |
|
Short breaks within work shifts
|
| • | Are breaks within shifts long enough and frequent enough to allow workers to rest, refresh and nourish themselves? |
|
Shift start/finish times
|
| • | Do any shifts start or finish between midnight and 6:00? |
| • | Are complex, difficult or strenuous tasks required at the start or end of such shifts? |
|
Changes to rosters
|
| • | Do workers get sufficient notice of roster changes? |
| • | Is fatigue management taken into account in roster changes? |
|
