Chapter 1 - Introduction


The purpose of this guide is to provide an overview of various tools and techniques to ensure that work schedules meet the requirements of a fatigue risk management system (FRMS).

An effective FRMS consists of several levels of fatigue hazard controls (see Developing and Implementing a Fatigue Risk Management System (TP 14575E) for a detailed discussion). One of the first things that companies need to examine is whether the schedule provides employees with an adequate opportunity to get enough sleep to be fit for work (Level 1 control).

Hazard-Control Model for Fatigue Risk Management

Hazard-Control Model for Fatigue Risk Management
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Designing a work schedule

In the past, hours-of-service (HOS) rules have been used to ensure that a schedule provides adequate sleep opportunity between shifts and does not result in significant work-related fatigue. In principle, this appears to be a reasonable strategy. However, HOS regulations designed to be applied generically to an entire industry can be inflexible and ineffective for an individual organization. They may not guarantee sufficient sleep opportunity.

In designing an FRMS, it is important to understand that there is no such thing as a perfect schedule. Work schedules need to be structured around competing needs, such as operational safety and employee family and social life. For example, the “family friendliness” of a work schedule is likely to be determined by how much time off it provides during times of high social value (i.e., afternoons, evenings, and weekends). The “sleep friendliness” of a work schedule depends on the breaks it provides during times of high sleep value (i.e., nights between 9 p.m. and 9 a.m.). While sleep should be the primary concern, other factors such as the family and social life of employees should be considered, because they can have a direct effect on whether employees are able to use the time off to sleep. Consulting with employees during the early stages of implementing an FRMS can help find a balance between these competing needs.

Providing adequate sleep opportunity

To determine whether a given schedule may result in work-related fatigue, calculate the sleep opportunity that it provides. There are various ways to do this. This document outlines two methods of managing sleep opportunity:

  • Automated fatigue audit systems. Biomathematical modelling software has been developed that can predict how much sleep an employee is likely to get in a given schedule. The software is able to calculate a fatigue likelihood score for each employee at any given point in the schedule.

  • Manual fatigue audit systems. For organizations with relatively simple schedules or that may not want to invest in software, manual calculations can also be performed to generate scores that provide an indication of fatigue likelihood.
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