Suggest guidelines for the design of shift schedule.My asked question is related with ergonomics topic - Shift Work

The previous answers focus on the impact of the schedule on the worker. My answer will focus on the reason for the schedule and how to design one to make the most efficient use of your personnel. There are 6 considerations:

1. Coverage requirements. The starting point for all schedule design should be the coverage requirements. If the facility operates 24/7, how many people need to be working at different times of the day? Does this stay the same throughout the week? For this discussion, let's assume that the facility needs 2 people working at all times.

2. Shift length. The most common shift lengths for 24 hour operations are 8 hours and 12 hours. The reason is that these divide evenly into a 24-hour day. Although 10-hour shifts are popular with employees, they don't divide evenly into 24 hours, making them a poor scheduling option.

3. Schedule format. Once the shift length is selected, the next question is the schedule format, i.e. whether you want fixed (permanent) shifts or rotating shifts. As a general rule, employees prefer fixed shifts while employers prefer rotating shifts. Before moving on, I would like to point out the 8-hour fixed shifts are often an inefficient scheduling option. You can use them, but it may require 1-3 more employees than other scheduling options.

4. Overtime. Most 24/7 schedules have a small amount of overtime built into them. If they didn't, there would be gaps in the coverage or the facility would have to hire more staff. Most organizations find that the overtime in the schedule is much less expensive than hiring adequate staff, especially when you consider the cost of benefits for the additional staff.

5. Pay week. Since most shift workers are non-salaried, they are subject to federal labor laws that require overtime premiums after 40 hours work per week. Although people don't think about this, the start of the pay week is important to schedule design for two reasons: (a) you don't want a schedule that creates unbalanced work weeks such as 32 hours one week and 48 hours the next week, and (b) you don't want to invoke overtime payments unnecessarily because the schedule didn't match the organization's pay week.

6. Schedule patterns. Once you addressed all the previous points, now is the time to consider different patterns of days worked and days off. With 8-hour shifts, the most popular patterns tend to be those that feature 7 consecutive days of work before having one or more days off. The reason is that this provides the maximum weekends off (1 every 4 weeks). With 12-hour shifts, there are several popular patterns such as Every Other Weekend Off, Long Break, 3-on-3-off, 4-on-4-off, split weekends, fixed-fixed, etc.

Of course there are other considerations such as shift start times, break policies, paid time-off policies, relief (absence) coverage, etc. that must be considered. But this gives you the high-level view of the schedule design process. You may be able to find schedule examples online, but the options will be limited and the potential problems (particularly the pay week) will be substantial.