Shiftwork, Work Scheduling and Safety: How Much Is Too Much

Transcription

1 Shiftwork, Work Scheduling and Safety: How Much Is Too Much Wayne S. Maynard, CPE, CSP, ALCM Liberty Mutual Group, Hopkinton, MA George E. Brogmus, MS, CPE, M.Erg.S. Liberty Mutual Group, Burbank, CA 10th Annual Applied Ergonomics Conference Celebrating The Past..Shaping The Future

2 Shiftworkers Problems Disturbed sleep Increased risk of accidents Impaired psychological health Impaired physical health Impoverished family/social life Employers Problems Increased errors/accidents Reduced productivity/quality Increased sickness absence Increased labour turnover Reduced moral

3 Paying For Overtime Overtime vs. Actual Work Output* = 29% = 48% = 52% = 74% = 82% Percent Productivity vs. Continuous Weeks of O/T 100 Pct Productivity Premium / Hr** = 94% = 166% **Premium is the additional cost of overtime, calculating labor at time and 1/2 over 40 hours divided by the equivalent hours of production output (actual work hours X Pct Productivity). 90 6, 9 Hr Days(47H) 80 6, 10 Hr Days(47H) 7, 8 Hr Days(42H) 7, 9 Hr Days(43H) 6, 12 Hr Days(48H) 7, 10 Hr Days(44H) , 12 Hr Days(40H) Weeks of Overtime 4 *Source: National Electrical Contractors Assn

4 Give me a Break - Please! Working Time Spontaneous Breaks Disguised Breaks Prescribed Breaks % 90% 11 Total Parts Produced: 3114! 80% 70% 60% Percent of Time 50% 40% Total Parts Produced: % % % 9.4 0% (Graf, 1954) 11.4 Lunch Only Lunch & 6 Breaks Type of Break Schedule Time to Complete One Part

5 Modelling Relative Risk (Folkard & Lombardi, 2004) We can estimate the Relative Risk for a work schedule by taking into account: 1. The length of the shifts (8h, 12h, etc) Shift Length>8hrs = Higher Risk 2. The type of shifts (Morning, Night, etc) Risk of Night > Afternoon > Day 3. The number of consecutive shifts ( days in a row without days off) Higher Risk with ^ Successive Days (^ for Night Shifts) 4. The interval between breaks (2h, 4h, etc) Higher Risk with Longer Time Between Breaks

6 Sample Schedules Reference: 8H X 5Days, Breaks Every 2H Estimated Relative Risk (Compared to 8H X 5 Days With Breaks Every Two Hours) Break Every Hour Break Every 2 Hours Break Every 4 Hours H X 4 Days Hours/Schedule: (48H) 12H X 4 Nights (48H) 12H X 5 Days 12H X 5 Nights 10H X 6 Days 10H X 6 Nights (60H) (60H) (60H) (60H) Schedule

7 Conclusions 1. Simple guidelines based on total work hours alone will be of very limited use in keeping risk within an acceptable limit. 2. The interactions of the basic work scheduling elements must be taken into account simultaneously.

8 Injury Risk Estimation Models Liberty Mutual s Work Scheduling Calculator is primarily based on Folkard s identification of good quality injury risk research. Currently for use by Liberty Mutual Consultants only; modeling described in Brogmus, 2006 in HFES Annual Meeting Proceedings. Designed to provide work scheduling guidance Provides the relative risk between two work schedules. UK s HSE (Spencer, et al, and Folkard, et al.) Includes risk and fatigue indices and allows for entry of exact work schedule (e.g., rotating, non-fixed schedule shifts, etc.) Available online: Initially designed to address evaluation requirements of the UK s Railway (Safety Critical Work) Regulations. Provides a risk index for a work schedule as compared to a rotating 12h shift with 2 Days on, 2 Nights on, 4 days off.

9 Liberty Mutual s Work Scheduling Injury Risk Estimator Pros Only 4 Required Inputs Based Solely on Direct Injury Research Graphical Representation of Impact of 1 or 2 Scheduling Factors Simultaneously Cons Complex Schedules Require Additional Manual Calculations

10 HSE (UK) Fatigue and Risk Index ABC 001 Day 4, 4, 3, Risk Index Pros Can enter detailed schedule, including complex ones Takes into consideration type of work and commuting time Incorporates Fatigue Research into Risk Index Graphical Representation of the Work Schedule Provided Graphical Representation of Risk Index over span of schedule Provides separate Fatigue and Risk Indices. Cons Requires detailed schedule input. Extrapolates from Fatigue Research and incorporates adjustments and assumptions on days off and commuting time into Risk Index. Provides separate Fatigue and Risk Indices Duty

11 Simple Demonstration Which Schedule Has Less Risk? Schedule A: 10 hours/day, 6 days/week, breaks every 2 hours (60 hours total/week) Schedule B: 9 hours/night, 5 days/week, breaks every 3 hours (45 hours total/week)

12 Reducing Shift Work Risks General Design Guidelines Day (morning) shifts are to be preferred over afternoon or night shifts. If additional hours are needed to meet production demands, it may be better to add hours to each shift or add an additional day of work. Limit work to 5 or 6 consecutive shifts in a row. Schedule work so that all workers have at least two rest days off in a row and that at least one of these days is Saturday or Sunday. Alternate weeks of overtime with weeks of normal time.

13 Reducing Shift Work Risks General Design Guidelines (continued) Avoid several days of work followed by 4 to 7 day mini-vacations, e.g., 10 to 14 days of work followed by 5-7 days off. These schedules should be used when there is no other choice, e.g., mining or oil exploration. Keep the schedule regular and predictable. (Studies of train accidents showed that very irregular schedules contributed to the accidents by producing sleep loss and fatigue.) Provide workers with 30 days notice for variable schedules.

14 Rest Breaks Provide for frequent rest breaks. Hourly breaks are appropriate for many kinds of work, but for highly repetitive or strenuous work, breaks more frequently than once each hour are necessary. How do your workers know when to take a break? How do you know if your workers have taken a break?

15 Night Work Guidelines Consider alternatives to permanent night shifts. Most workers never get fully used to night shift work, since they go back to a daytime schedule during days off. Keep consecutive night shifts to a minimum. Only 2 to 4 nights in a row should be worked before a couple of days off. Keep night work at an average of 48 hours per week, allowing up to six 8-hour night shifts or four 12-hour night shifts per week. Avoid quick shift changes and adjust shift length to the workload. When changing employees' work schedules, consider all aspects of the worker's job and home life.

16 Night Work Guidelines (continued) Increase employee awareness and ability to cope with night work by the need to get good sleep. A good-quality mattress! Establishing a sleep routine that works best for the individual including: utility of exercise, diet, and relaxation techniques to reduce stress. Use black-out drapes, turn off phones and pagers, use a fan or white noise source to mask daytime noises. NIOSH s publication, Plain Language About Shiftwork (Rosa and Colligan, 1997 available for free download), provides additional helpful practical advice.

17 Summary Research on work scheduling and injury risk is good enough to give DIRECTIONS for improvements, but the limited scope of some of the research demands CAUTION. The interaction of different work scheduling factors is complex enough so that software can help organizations understand the impact of work scheduling on injury risk. Liberty Mutual and HSE have developed software to help compare schedules for injury risk, but it is not the whole story in any real-life work situation. Employers MUST consider non-injury implications of work scheduling decisions such as productivity, overtime pay, and staffing considerations. There are many practical improvements that employers can make that can mitigate the effects of alternative work schedules.