The earliest 24/7 schedules were based on 8-hour rotating shifts. These schedules require employees to rotate through all three shifts: days, afternoons, and nights. Most of them use 4 equal-sized crews. If the company needed 8 people working around-the-clock, they would have 8 employees on each of the crews. Three crews would be working each day of the week (one on each shift) while the fourth crew was off. The different work patterns vary in the number of days worked before getting time off and how long it takes to get to the next shift.

In this article, we will look at the two key features of 8-hour rotating shift schedules: (1) consecutive days of work, and (2) speed of rotation.

 

Consecutive Days of Work

As a general rule, the more consecutive days of work, the longer the breaks (days off) and the more frequent the weekends off. Unfortunately, when you increase the days of work, sleep debt accumulates. Choosing from different work patterns thus involves a tradeoff between increased fatigue and more attractive time off.

The Continental shift schedule, one of the earliest and most popular patterns, required working 7 shifts in a row before getting 2 or 3 days off. This schedule had one full weekend off every 4 weeks.

Many employees found that working 7 consecutive shifts was too much, so they insisted on working fewer days in a row. A pattern with 6 consecutive shifts (the Metropolitan Plan) only offered one weekend off every 8 weeks. A pattern with 5 consecutive shifts only offered one weekend off every 10 weeks, and those occurred back-to-back, so that employees would have to go 18 weeks without a weekend off. Ouch!

Here's a table that compares 4 most common patterns:

 

	5 Days	6 Days	7 Days	7 Days
Sat-Sun off	every 10 weeks	every 8 weeks	every 4 weeks	every 4 weeks
Max. days off	2	2	3	4
Min. days off	1	2	2	1

 

 

Speed of Rotation

Some employees prefer to rotate quickly from shift-to-shift. That way, they don’t have to work a bunch of night shifts all at once. The Continental is a good example of a fast rotation. Here’s what that pattern looks like:

 

 

 

Crew / Week	Thu	Fri	Sat	Sun	Mon	Tue	Wed	Hours
A / Week 1	-	-	D8	D8	A8	A8	N8	40
B / Week 2	N8	N8	-	-	D8	D8	A8	40
C / Week 3	A8	A8	N8	N8	-	-	D8	40
D / Week 4	D8	D8	A8	A8	N8	N8	-	48
							Average	42

Key:

D8 = 8-hour day shift

A8 = 8-hour afternoon shift

N8 = 8-hour night shift

 

This is a 4-week, rotating schedule operated by four crews. When the schedule first starts, the crews are assigned to specific weeks in the cycle. For example, Crew A is assigned to start in Week 1 and Crew B is assigned to start in Week 2, and so on. At the end of each week, the crews rotate down to the next week in the cycle. Crew A moves to Week 2, Crew B moves to Week 3, etc. When a crew completes the 4^th week, they rotate up to Week 1.

 

For companies that want a slower rotation, they could simply devote each block of days to a single shift, as shown below:

 

Crew / Week	Thu	Fri	Sat	Sun	Mon	Tue	Wed	Hours
A / Week 1	-	-	D8	D8	D8	D8	D8	40
B / Week 2	D8	D8	-	-	A8	A8	A8	40
C / Week 3	A8	A8	A8	A8	-	-	N8	40
D / Week 4	N8	N8	N8	N8	N8	N8	-	48
							Average	42

Key:

D8 = 8-hour day shift

A8 = 8-hour afternoon shift

N8 = 8-hour night shift

 

With this adjustment, the rotation is slowed to once a week. The other two patterns (6 days and 5 days) also rotate shifts on a weekly basis. This is still too fast for many people, but a slower rotation can be difficult to achieve.

 

One approach is to increase the number of crews from 4 to either 9 or 12. It’s not as efficient (i.e., it requires a slightly larger staff), but it will slow the shift rotation to once every 3 or 4 weeks.

 

The ultimate approach is to adopt a fixed shift pattern and then re-allocate the employees to different shifts periodically, such as every 6 or 12 months. This also may require a few additional employees since 8-hour fixed shift schedules are not as efficient as 8-hour rotating shift schedules.

 

Summary

8-hour rotating shift schedules have two key features: consecutive days of work and speed of rotation. 

 

The most attractive schedules for employees in terms of time off require them to work 7 shifts in a row. Unfortunately, this is really tough on sleep. That’s why some employees would rather work fewer consecutive shifts, even though they get fewer weekends off.

 

Some employees prefer a fast shift rotation so they only work 2 or 3 night shifts in a row. Most employees, however, prefer a much slower rotation. This can be achieved by increasing the number of crews or by adopting a fixed shift schedule and having employees change shifts every 6 or 12 months.

 

As a general rule, employees prefer fixed shifts while employers prefer rotating shifts (Fixed shifts vs. rotating shifts). Because of this, many companies migrated to 8-hour fixed shifts or longer shift lengths (usually 12-hour shifts). Fixed shifts eliminated the need to change shifts, which helped to reduce fatigue and improve predictability (Schedule Consistency & Predictability). Longer shifts resulted in more days off and more weekends off, which also helped reduce fatigue (12 Hour Shifts).