Elimination and Substitution
Elimination and substitution, while most effective at reducing hazards, also tend to be the most difficult to implement in an existing process. If the process is still at the design or development stage, elimination and substitution of hazards may be inexpensive and simple to implement. For an existing process, major changes in equipment and procedures may be required to eliminate or substitute for a hazard.
These strategies are considered first because they have the potential to completely eliminate the hazard, thus greatly reducing the probability of an accident due to the hazard.
Some examples of these two strategies include:
- Removing the source of excessive temperatures, noise, or pressure - this is "elimination".
- Substituting a toxic chemical with a less toxic or non-toxic chemical - this is "substitution".
Engineering Controls
Engineering controls to reduce exposure to infectious diseases through the design of equipment. The advantage of using engineering controls is that they reduce exposure to hazards without relying on worker behavior and can be the most cost-effective solution to implement. Engineering controls for SARS-CoV-2 and other viruses include:
- Installing high-efficiency air filters.
- Increasing ventilation rates in the work environment.
- Installing physical barriers, such as clear plastic sneeze guards.
- Installing a drive-through window for customer service.
- Specialized negative pressure ventilation in some settings, such as for aerosol generating procedures (e.g., airborne infection isolation rooms in healthcare settings and specialized autopsy suites in mortuary settings).
Ensuring adequate ventilation throughout the work environment can help to maintain a safe and healthy workplace. Employers should work with a heating, ventilation, and air conditioning (HVAC) professional to consider steps to optimize building ventilation. An HVAC professional can ensure that the ventilation system is operating as intended.
- Encourage workers to stay home if they are sick.
- Ensure all HVAC systems are fully functional, especially those shut down or operating at reduced capacity during the pandemic.
- Remove or redirect personal fans to prevent blowing air from one worker to another.
- Use HVAC system filters with a Minimum Efficiency Reporting Value (MERV) rating of 13 or higher, where feasible.
- Increase the HVAC system’s outdoor air intake. Open windows or other sources of fresh air where possible.
- Be sure exhaust air is not pulled back into the building from HVAC air intakes or open windows.
- Consider using portable high-efficiency particulate air (HEPA) fan/filtration systems to increase clean air, especially in higher-risk areas.
- When changing filters, wear appropriate personal protective equipment. ASHRAE recommends N95 respirators, eye protection (safety glasses, goggles, or face shields), and disposable gloves.
- Make sure exhaust fans in restrooms are fully functional, operating at maximum capacity, and are set to remain on.
- Encourage workers to report any safety and health concerns.
Knowledge Check Choose the best answer for the question.
2-2. Installing high-efficiency air filters is an example of _____.
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