Detail the hierarchy of controls as it applies to ergonomics, and explain the priority of engineering controls over personal protective equipment in managing workplace risks.
The hierarchy of controls is a systematic approach used to manage and minimize workplace risks, including ergonomic hazards, by prioritizing control methods based on their effectiveness. It arranges controls in descending order of effectiveness, with the most effective controls aimed at eliminating the hazard altogether and the least effective controls being those that rely on worker behavior. The hierarchy consists of five levels: elimination, substitution, engineering controls, administrative controls, and personal protective equipment (PPE). Understanding this hierarchy is crucial in developing comprehensive ergonomic strategies.
1. Elimination: This is the most effective control and involves removing the hazard completely from the workplace. In ergonomics, this might mean eliminating a task or process that poses a high risk. For example, if a production line requires repetitive heavy lifting of materials from the floor level, the most effective measure would be to eliminate the need to lift the materials altogether by changing the process flow or bringing materials directly to the work level via automated delivery systems.
2. Substitution: Substitution involves replacing a hazardous material or process with a less hazardous one. In ergonomic terms, this might mean replacing a manual tool that requires awkward postures with a powered or automated tool that reduces strain and promotes more neutral positions. An example could be replacing a heavy manual hammer with an automatic nail gun that requires less force and reduces the wrist strain associated with repetitive hammering.
3. Engineering Controls: Engineering controls involve modifying the workplace or equipment to reduce the exposure to hazards. This includes changes to equipment, workstations, or the environment. For instance, installing adjustable workstations that allow workers to adjust their work surface height to match their individual stature and reduce the need to bend, reach, or stretch awkwardly. Using ergonomic tools such as angled screwdrivers or spring-loaded scissors which minimize wrist deviation is another example of using engineering controls. Another good example is using material handling equipment like lift tables, conveyors and pneumatic hoists to reduce the need for manual lifting and carrying. These controls are proactive in minimizing risk at its source, making them very effective at reducing risk.
4. Administrative Controls: These controls involve changing the way work is done, including work schedules, policies, and training procedures. Administrative controls rely on human actions, rather than direct physical changes to equipment or the environment. Task rotation which involves moving employees between different jobs that use different muscle groups throughout the day reduces prolonged exposure to certain tasks. Job modifications, such as redesigning the way an existing task is performed to minimize awkward movements are another form of administrative control. Implementing rest breaks and training on proper lifting techniques, body mechanics, and ergonomic principles also falls under the administrative control umbrella. These are less effective than engineering controls because they rely on consistent adherence to rules and practices, which can be influenced by variables such as stress or fatigue.
5. Personal Protective Equipment (PPE): PPE is the least effective control because it does not eliminate the hazard, but only protects the worker from it. In ergonomics, PPE might include wrist braces, back belts, or padded gloves. While these can provide some short-term comfort and support, they do not address the root cause of the ergonomic hazard. PPE relies heavily on user compliance, is vulnerable to improper fitting, and may not fully prevent injury. Relying only on PPE can give a false sense of security and does not address the underlying systemic issues that cause the ergonomic risks.
The priority of engineering controls over PPE is fundamental in managing workplace ergonomic risks effectively for a number of reasons. Engineering controls are designed to proactively reduce or eliminate hazards at their source. By implementing changes to the workplace or equipment, engineering controls reduce the exposure of workers to the hazard, regardless of worker behavior or consistency. For instance, the implementation of adjustable workstations helps to directly eliminate the cause of poor posture and thus reduce risk of MSDs regardless of whether a worker has been trained on proper posture techniques. In contrast, PPE does not eliminate the source of risk; it only reduces the impact of that risk on the individual using the equipment. For example, a wrist brace will not stop a worker from having to do repetitive motions, it only offers a layer of protection, and it only works correctly if worn properly.
Engineering controls are also more reliable than PPE because they do not rely on human adherence or proper usage. Unlike PPE, which can be forgotten, worn incorrectly, or fail due to wear and tear, engineering controls are built into the workplace or equipment and consistently provide the safety measure without ongoing intervention from the worker. Additionally, engineering controls are more effective in the long term as they eliminate hazards proactively rather than merely reducing their impact. By making the workplace safer at a fundamental level, they reduce the risk of injuries, improve productivity, and create a healthier and more positive work environment. While PPE is necessary as a secondary layer of protection, it is never the first option when implementing ergonomic interventions, because it does not solve the underlying cause of the ergonomic risk.