Safety experts are familiar with the Hierarchy of Controls, or the Hierarchy of Ergonomics Controls, in this case. That is, once a hazard is identified, we should look for ways to gain control over that hazard, and the Hierarchy provides guidance as we research, implement and verify improvements.
The Hierarchy of Controls is not just a theoretical suggestion. It’s a well tested and proven systematic approach to reducing hazards and complying with standards such as ISO 45001:2018, which states:
The organization shall establish, implement and maintain a process(es) for the elimination of hazards and reduction of OH&S risks using the following hierarchy of controls:
A common way to show the Hierarchy is an inverted pyramid, such as this one, from NIOSH.
Ergonomics control methods at the top of graphic are usually much more effective and protective than those at the bottom. Since ergonomics hazards are often more complex and multifactorial than traditional safety concerns, it’s common to apply a combination of control strategies to achieve practical solutions for the near- and long-term. For example, we might apply some combination of Administrative Controls as our initial hazard reduction approach while we research and implement more effective Elimination, Substitution and Engineering Controls that will be phased in over time.
Completely remove the hazard from the process, or replace the hazardous process element(s) with a non-hazardous or less-hazardous one. These controls are typically most effective, but may take more time and resources to implement. Implementation costs may be higher than other control options, but when well integrated with the overall process, can also provide significant payback in other process metrics like productivity and quality.
Isolate people from the hazard, or reduce the hazard severity through physical design changes to the workstation or process flow. When well implemented, these controls are more effective than Administrative or PPE controls. The initial cost of engineering controls can be higher than the initial cost of administrative controls or PPE, but over the longer term, total costs are often lower, and may provide cost savings in other process metrics like productivity and quality.
Change the way people work when exposed to a hazard, or the length of time they are exposed to the hazard, or use equipment (often wearable) intended to protect individuals from the hazard. Administrative controls and PPE programs may seem relatively inexpensive to establish but, over the long term, can be very costly to sustain, and have been proven less effective than other controls.
A good ergonomics improvement process begins by identifying and quantifying ergonomics hazards, then applies a continuous improvement problem solving strategy that draws from this hierarchy of controls. Significant improvements are sometimes achieved quickly, and in other cases may be applied incrementally over time.
Ergoweb Enterprise™ is a cloud-based ergonomics management software that allows companies to control their ergonomics programs and fulfill EHS regulation standards. The comprehensive system provides the necessary tools and resources to assess, quantify, and track improvement projects over time, creating a sustainable ergonomics initiative that pays for itself many times over. Request your live demonstration today.
A workcell receives incoming components on a pallet placed by hand-truck on the shop floor. Workers walk an average of 20 feet to retrieve components from the pallet, return to their workstations where they perform assembly tasks, then carry and place their completed product on another pallet located roughly 15 away. An ergonomics analysis of the workcell revealed that the lifting tasks created an injury hazard and presented barriers to smooth flow and product quality.
The following table describes several possible improvement strategies organized within the Hierarchy of Controls:
|Control||Example Hazard: Lifting|
|Elimination & Substitution||A conveyor system was installed that delivered incoming product directly to each operator rather than delivering by pallet. When assembly is completed, the operators slide the completed product onto a conveyor that delivers it to the next process. |
Benefits included completely eliminating the lifting hazards, reducing product damage and waste from multiple handlings and wasteful motions, safely improving flow, quality and cycle time. However, the overall cost and time to implement was long, and required cross-functional teaming and the recognition and alignment of value for all concerns.
|Engineering||The workcell was rearranged to minimize required carrying distances while accessing the pallets, and pallet placement was modified to keep the lifting height range as close to waist height as possible. Since variations in individual height and the height of the stacked pallets caused some workers to bend low and others to reach high, adjustable height and angle pallet lifts were installed, allowing adjustments closer to waist height lifting.|
Benefits included a significantly reduced lifting hazard and measurable improvements in flow and product quality. However, some level of lifting exposure remained, and the shortest workers were not entirely accommodated.
|Administrative & PPE (Personal Protective Equipment)||A job rotation scheme was developed to reduce the amount of time each individual worker was exposed to the lifting hazard, but little could be accomplished because manual lifting was central to the work process. Workers were also trained in proper lift technique and encouraged to participate in a stretching and strengthening program, customized to their specific tasks, and intended to make them more resilient to the lifting hazard. They were also issued back belts (back belts are not recommended by Ergoweb), which required additional training and PPE program management.|
Hierarchy of Controls, https://www.cdc.gov/niosh/topics/hierarchy/default.html
ISO 45001:2018, Occupational health and safety management systems — Requirements with guidance for use, https://www.iso.org/iso-45001-occupational-health-and-safety.html
No Evidence That Back Belts Reduce Injury Seen in Landmark Study of Retail Users, https://www.cdc.gov/niosh/updates/beltinj.html
About the Author
Peter Budnick is the founder and president of Ergoweb, LLC – a 24-year old company that helps clients manage their ergonomics programs through its flagship service Ergoweb Enterprise™ – a cloud-based continuous improvement ergonomics management software. He is an industry leader in the ergonomics software space, has published extensively, and been a featured speaker at conferences, corporations, and training events. Peter’s extensive leadership roles include Director and President for the Board of Certification in Professional Ergonomics (BCPE), Chair of the International Ergonomics Association’s (IEA) Certification Subcommittee, and others. He is a Certified Professional Ergonomist (CPE) and holds a B.S. in Engineering from Michigan Technological University, a M.S. in Industrial Engineering from the University of Michigan, and a Ph.D. in Mechanical Engineering from the University of Utah.