There are advantages and disadvantages for 12-hour shifts.
More days off. Workers on a 12-hour shift get 182 days off per year over the 92 days of 8-hour shift. Fewer days at work provides more time for other activities.
Long weekends. Workers on 12-hour shifts have long 3-day weekends every other weekend and are guaranteed every other weekend off.
Fewer consecutive days worked. Workers on 12-hour shifts never work more than two days in a row, reducing problems of stress and cumulative fatigue.
Less commuting required. Fewer days at work mean fewer days of driving to and from work. This represents time saving and reduced transportation costs for employees with longer commutes.
Improved family and social life. Shiftworkers often report improved family life because there are more “quality” days off to spend at home. Shiftworkers on 12-hour schedules report less irritability, more communication and better planning of family activities.
Improved morale. Having more days off relieves stress and improves shiftworkers outlook and attitude. Family members can often become more supportive, further helping morale.
More frequent “recuperation” or “recovery” days. These recovery days occur after blocks of scheduled shifts, so shiftworkers feel more alert and energetic both on and off the job. Many shiftworkers need a recovery day, particularly after working nights, to catch up on sleep. With an 8-hour schedule these recovery days can consume most of the days off, leaving too little quality time for family and friends and preventing the shiftworker from feeling well rested and energetic.
Better use of vacation time. Although there are technically fewer vacation days on 12’s versus 8’s, by taking only 2, 3 or 4 vacation days at the appropriate time in the cycle, it is possible to have up to 12 consecutive days off. Thus extended vacations are possible several times per year. With 8-hour shifts it takes 5 vacation days to get a week off.
Increased utilization of personal time. With 12-hour shifts, shiftworkers have more consecutive days off and more total days off. They report that they are able to get more done at home, take care of more personal business and shopping during the week, and schedule more family and social events. With 8-hour schedules, there are seldom enough consolidated blocks of time for extended home projects and social activities.
Elimination of double shifts and/or holdovers. Sixteen-hour shifts on short notice (back-to-back 8 -hour shifts) to cover for absences can be eliminated. On 12-hour shifts, shiftworkers usually know exactly how long they will be working, and they can prepare and pace themselves accordingly. This benefit is offset by the degree to which workers get called in unexpectedly on their days off to cover a 12-hour shift, which in turn depends upon the success of their voluntary overtime sign up list as well as overall plant staffing levels.
Little effect on overtime opportunities. For continuous operations, 12-hour shift schedules do not add to or reduce the amount of real overtime required. In 24/7 operations, overtime is a function of staffing level rather than the shift schedule, since all positions have to be filled regardless of shift length.
Elimination of evening shifts. The least desired shift on an 8-hour schedule is usually the evening shift which keeps the shiftworkers isolated from family and friends for extended periods of time. 12-hour shifts minimize this problem because shift changeover times usually allow more contact with the family in the evenings. For example, a typical 8-hour evening shift runs between 3-11 p.m. and provides little to no family time in the evening. In comparison, a typical 12-hour schedule has shift start times between 6-8 a.m. and 6-8 p.m. Thus, most shiftworkers can spend some amount of quality time with their family either before or after the shift.
Limited family and social time during working days. Shiftworkers may have less opportunity to see their spouses and children on working days. Child care and day care conflicts may also occur, since many babysitters may be unable to extend their hours and the hours of child care facilities do not correspond with shift schedules. Single workers may find it more difficult to schedule dates and activities with friends.
Sleep schedule inflexibility. Hours away from work during a work day are limited, so a shiftworker’s optimal timing and amount of sleep may be a challenge to achieve. Sleep schedule disruption can potentially occur because of the reduced flexibility for sleep time. In contrast, on an 8-hour schedule, night shift workers can choose to sleep in the morning when they return home or stay up in the morning and sleep later in the day, depending on their sleep physiology. Twelve-hour shiftworkers do not have this flexibility, and when working nights they need to condition themselves to sleep in the morning and into the early afternoon.
Irregular pay weeks. Most 12-hour schedules have alternating pay weeks of 36 and 48 hours. This can make it more difficult for a worker to budget his or her finances, since most people plan their finances based on a 40 hour week.
Concerns of older workers. Older shiftworkers respond less favorably toward 12-hour shifts than younger workers. Many older workers are less enthusiastic about making any schedule changes, because this may disrupt their established work and social routines. They may also feel that 12 hours is simply too long for a regularly scheduled work period. In fact, it is physiologically more difficult for someone in their mid 50’s or 60’s to sustain vigilance for longer periods of time than it is for someone younger. There also may be fewer reasons for the older shiftworker to want to compress the work week by working longer hours; i.e., they no longer have children living at home, and frequent vacations or long breaks may be less important
Reduced tolerance of long commutes. With a 1-hour commute to work (each way), the actual time away from home for the shiftworker may approach 14 hours or more. This leaves time for sleeping and meals and little else. Daily recreational activity and exercise regimens may be compromised. Distance from home to the plant may thus become more important on 12-hour shifts.
Difficulties in scheduling meetings. Twelve hours is typically as long as most workers want to be on-site. Thus, if shiftworkers are asked to stay over after the night shift for training or plant meetings, the workday may be unacceptably lengthened. Consequently, many employers with 12-hour schedules conduct training and other meetings on “scheduled days off.”
Survey data and anecdotal information suggests that the majority of shiftworkers prefer coming in on days off for meetings (rather than staying after a shift), as long as the meetings are planned well in advance, don’t last more than four hours, and occur no more than once during a four week period.
Reduced tolerance to physically demanding jobs. Such jobs can be more difficult on 12-hour shifts. Unless countermeasures are taken to alleviate the problem, there may be an increase in work-related injuries and a rise in general discomfort, such as aching feet and backs. Solutions include reworking certain job processes or rotating jobs during a shift, and many physical complaints are mitigated by the increased number of recovery days.
More pay lost when a day is missed. On occasions when shiftworkers take an unpaid day off, they may lose the equivalent of 33% more pay during their absence as compared to 8-hour shifts. This magnifies their personal financial loss from absences. However, the increased number of days off means that sickness has a better than 50% likelihood of occurring during a day off, instead of on a work day.
Driver fatigue returning home. Drowsiness when driving is always a concern, since it is not uncommon for workers on any type of schedule to feel drowsy or to “fight” sleep while driving home. The already difficult task of staying awake while driving home after working an 8-hour midnight shift might be assumed to be even more difficult after working a 12-hour shift. However, this concern is linked much more strongly to the time of day of commuting than to the length of the shift. Thus alertness training and other precautions can help reduce the risk of driver fatigue.
Fast-rotating 12-hour schedules. Certain schedules can cause sleep problems when “flip-flop-ping” from nights to days, because it’s hard for one’s body to adjust to frequent changes. This problem can be minimized with a well-designed, biocompatible schedule that provides for sufficient recovery time between rotations.
Longer hours away from home in the evenings. Extended work hours may be undesirable from the standpoint of family and home security. Watchdogs, alarm systems, and networks of telephone friends can alleviate these concerns.
Increased percentage of night shifts. Instead of only one-third of work shifts being night shifts on an 8-hour schedule, one-half of the shifts are night shifts on a 12-hour schedule. This is of course counterbalanced by the reduced number of shifts worked, and also by the fact that half of the work time will occur during the day shift.