Here’s a true story: I was recently speaking with one of my husband’s friends. He said he was an engineer, following it up by saying, “I drive trains”. I excitedly began discussing the applications of SAFTE-FAST for fatigue risk management in the rail industry. Well, he turned out to be joking; he’s actually an engineer in the construction industry. I guess I should have known he didn’t drive trains from the lack of pin-striped overalls and hat. But Pandora’s “let’s talk about fatigue” box had been opened. I’m embarrassed to say that I didn’t really think about construction as being a fatigue-sensitive industry. I assumed that construction sites had to be closed at night to allow superheroes to have karate fights with bad guys. Upon learning that construction workers can do shift work, I declared, “I’m going to blog about this!”, which is always a good thing to shout to let people know how cool you are.
Construction is a hazardous occupation that accounts for a disproportionately large percentage of work-related injuries (Ringen, Seegal et al. 1995, Goldenhar, Hecker et al. 2003). Surely then, fatigue must be a contributor. A good place to start when trying to understand fatigue risk in a new population is to check out the industry-specific regulations surrounding work hours. For blog length purposes, I will give only a brief overview of rules regarding work hours in construction in the United States. Construction workers’ hours are covered by the Fair Labor Standards Act (FLSA) (https://www.dol.gov/sites/dolgov/files/WHD/legacy/
files/whdfs1.pdf;) (Mayer, Collins et al. 2013). This act requires employers to establish a workweek and pay overtime when hours worked exceed 40 hours in the workweek. Paying overtime only after 80 hours in a bi-weekly pay period is illegal. While exemptions exist for this rule, they do not apply to manual laborers unless they are in a managerial position. There may be workarounds to these rules, like hiring temporary workers or contractors. The heavy influence of workers’ unions in the construction industry may limit the prevalence of these practices, but I could not find any hard numbers on it. Workers in the construction industry can choose to join a number of trade unions (https://nabtu.org/). If you’re familiar with unions, feel free to skip to the next paragraph. If you aren’t, the goal of unions is to create work opportunities, ensure sufficient wage compensation, protect the safety, and fight for their members’ best interests in general. Unions are a lot like mothers, especially when it comes to people’s complex personal feelings about them.
In short, working hours in the construction industry are reasonably regulated. In theory, this should limit the potential for fatigue risk. Perhaps that is why the National Institute for Occupational Safety and Health (NIOSH) Directory of Construction Resources (https://www.cdc.gov/niosh/construction/default.html) did not feature a sub-topic on fatigue. However, I did notice that musculoskeletal disorders, opioid use, and suicide risk were all featured topics. In a previous analysis of predictors of non-deployability in US soldiers, I had been surprised to find that soldiers with documented sleep problems were over one and a half times more likely to also experience accidents or injuries than soldiers with no sleep problems (Devine, Collen et al. 2020). Similarly, sleep problems are strongly associated with opioid use disorder and suicide risk (Cronin, Keifer et al. 1995, Burke, Peirce et al. 2008, Bernert, Kim et al. 2015, Cheatle and Webster 2015, Bertz, Epstein et al. 2019, Liu, Steele et al. 2020, Geoffroy, Oquendo et al. 2021). Could fatigue be an underlying factor for safety risks in the construction industry as well? The plot thickens.
The short answer is yes. In an observational study of Canadian construction workers, study participants exhibited an estimated increased risk of accident by almost 9% solely due to inadequate sleep (Powell, Copping et al. 2010). Work problems and psychological distress were found to be associated with sleep problems in construction professionals using structural equation modeling (Bowen, Govender et al. 2018). An analysis of 450 construction workers located in India showed a 15% increased risk of injury for laborers due to insufficient sleep (Sathvik and Krishnaraj). Even construction professionals who only worked days reported getting less than 6 hours of sleep per night and indicated that near-misses may be more likely to occur because of sleep deprivation (Gatti, Lin et al. 2014). These findings all jive with what we know about the contribution of fatigue due to sleep loss to overall worker safety. What I did find interesting, however, was how many articles I found that aimed to tease apart factors contributing to accidents, injury, substance use, or mental health in the construction industry that did not account for sleep-related fatigue-- (Sawacha, Naoum et al. 1999, Chen, McCabe et al. 2017, Alruqi and Hallowell 2019) to name a few. The contribution of fatigue to overall risk cannot be quantified if it is not measured. This constitutes a potential oversight on the part of analysts trying to visualize safety risks in construction.
You are probably wondering at this point if biomathematical modelling of fatigue has been applied to construction work. After all, SAFTE-FAST features a shiftwork template that could easily be adapted to scheduling for construction workers. Tideway, the company delivering the Thames Tideway Tunnel ‘super sewer’ project in London, recently funded a workshop to investigate how biomathematical models are used within the tunnelling sector of construction (Pilkington-Cheney, Filtness et al. 2020). The researchers and tunnelling experts involved in the workshop agreed that biomathematical models have the potential to be effective for fatigue mitigation in the tunneling sector and construction in general, but stressed that a model must be adapted to be industry-specific. At the moment, there seems to be a communication gap between analysts who are trying to understand risk indicators in construction but leave fatigue off the list, and operational researchers who have neglected to view construction as a fatigue-sensitive industry. I’m looking forward to engaging more on this topic and bridging that communication gap in the future. It shouldn’t be hard. After all, construction workers are pretty good at building bridges.